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# The MariaDB sys schema

A collection of views, functions and procedures to help MariaDB administrators get insight into MariaDB Database usage.

There are install files available. To load these, you must position yourself within the directory that you downloaded to, as these top level files SOURCE individual files that are shared across versions in most cases (though not all).

## Overview of objects

### Tables

#### sys_config

##### Description

Holds configuration options for the sys schema. This is a persistent table, with the configuration persisting across upgrades (new options are added with `INSERT IGNORE`).

Its structure is as follows:

```SQL
+----------+--------------+------+-----+-------------------+-----------------------------+
| Field    | Type         | Null | Key | Default           | Extra                       |
+----------+--------------+------+-----+-------------------+-----------------------------+
| variable | varchar(128) | NO   | PRI | NULL              |                             |
| value    | varchar(128) | YES  |     | NULL              |                             |
| set_time | timestamp    | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| set_by   | varchar(128) | YES  |     | NULL              |                             |
+----------+--------------+------+-----+-------------------+-----------------------------+
```

Note, when functions check for configuration options, they first check whether a similar named user variable exists with a value, and if this is not set then pull the configuration option from this table in to that named user variable. This is done for performance reasons (to not continually `SELECT` from the table), however this comes with the side effect that once inited, the values last with the session, somewhat like how session variables are inited from global variables. If the values within this table are changed, they will not take effect until the user logs in again.

##### Options included

| Variable                             | Default Value | Description                                                                    |
| ------------------------------------ | ------------- | ------------------------------------------------------------------------------ |
| statement_truncate_len               | 64            | Sets the size to truncate statements to, for the `format_statement()` function. |
| statement_performance_analyzer.limit | 100           | The maximum number of rows to include for the views that does not have a built-in limit (e.g. the 95th percentile view). If not set the limit is 100. |
| statement_performance_analyzer.view  | NULL          | Used together with the 'custom' view. If the value contains a space, it is considered a query, otherwise it must be an existing view querying the performance_schema.events_statements_summary_by_digest table. |
| diagnostics.allow_i_s_tables         | OFF           | Specifies whether it is allowed to do table scan queries on information_schema.TABLES for the `diagnostics` procedure. |
| diagnostics.include_raw              | OFF           | Set to 'ON' to include the raw data (e.g. the original output of "SELECT * FROM sys.metrics") for the `diagnostics` procedure.|
| ps_thread_trx_info.max_length        | 65535         | Sets the maximum output length for JSON object output by the `ps_thread_trx_info()` function. |

### Views

Many of the views in the sys schema have both a command line user friendly format output, as well as tooling friendly versions of any view that contains formatted output duplicated as an x$ table.

The examples below show output for only the formatted views, and note where there is an x$ counterpart available.

#### host_summary / x$host_summary

##### Description

Summarizes statement activity, file IO and connections by host.

When the host found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc host_summary;
+------------------------+---------------+------+-----+---------+-------+
| Field                  | Type          | Null | Key | Default | Extra |
+------------------------+---------------+------+-----+---------+-------+
| host                   | varchar(60)   | YES  |     | NULL    |       |
| statements             | decimal(64,0) | YES  |     | NULL    |       |
| statement_latency      | text          | YES  |     | NULL    |       |
| statement_avg_latency  | text          | YES  |     | NULL    |       |
| table_scans            | decimal(65,0) | YES  |     | NULL    |       |
| file_ios               | decimal(64,0) | YES  |     | NULL    |       |
| file_io_latency        | text          | YES  |     | NULL    |       |
| current_connections    | decimal(41,0) | YES  |     | NULL    |       |
| total_connections      | decimal(41,0) | YES  |     | NULL    |       |
| unique_users           | bigint(21)    | NO   |     | 0       |       |
| current_memory         | text          | YES  |     | NULL    |       |
| total_memory_allocated | text          | YES  |     | NULL    |       |
+------------------------+---------------+------+-----+---------+-------+
12 rows in set (0.15 sec)

mariadb> desc x$host_summary;
+------------------------+---------------+------+-----+---------+-------+
| Field                  | Type          | Null | Key | Default | Extra |
+------------------------+---------------+------+-----+---------+-------+
| host                   | varchar(60)   | YES  |     | NULL    |       |
| statements             | decimal(64,0) | YES  |     | NULL    |       |
| statement_latency      | decimal(64,0) | YES  |     | NULL    |       |
| statement_avg_latency  | decimal(65,4) | YES  |     | NULL    |       |
| table_scans            | decimal(65,0) | YES  |     | NULL    |       |
| file_ios               | decimal(64,0) | YES  |     | NULL    |       |
| file_io_latency        | decimal(64,0) | YES  |     | NULL    |       |
| current_connections    | decimal(41,0) | YES  |     | NULL    |       |
| total_connections      | decimal(41,0) | YES  |     | NULL    |       |
| unique_users           | bigint(21)    | NO   |     | 0       |       |
| current_memory         | decimal(63,0) | YES  |     | NULL    |       |
| total_memory_allocated | decimal(64,0) | YES  |     | NULL    |       |
+------------------------+---------------+------+-----+---------+-------+
12 rows in set (0.00 sec)
```

##### Example

```SQL 
  mariadb> select * from host_summary;
  +------+------------+-------------------+-----------------------+-------------+----------+-----------------+---------------------+-------------------+--------------+
  | host | statements | statement_latency | statement_avg_latency | table_scans | file_ios | file_io_latency | current_connections | total_connections | unique_users |
  +------+------------+-------------------+-----------------------+-------------+----------+-----------------+---------------------+-------------------+--------------+
  | hal1 |       2924 | 00:03:59.53       | 81.92 ms              |          82 |    54702 | 55.61 s         |                   1 |                 1 |            1 |
  +------+------------+-------------------+-----------------------+-------------+----------+-----------------+---------------------+-------------------+--------------+
```

#### host_summary_by_file_io / x$host_summary_by_file_io

##### Description

Summarizes file IO totals per host.

When the host found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc host_summary_by_file_io;
+------------+---------------+------+-----+---------+-------+
| Field      | Type          | Null | Key | Default | Extra |
+------------+---------------+------+-----+---------+-------+
| host       | varchar(60)   | YES  |     | NULL    |       |
| ios        | decimal(42,0) | YES  |     | NULL    |       |
| io_latency | text          | YES  |     | NULL    |       |
+------------+---------------+------+-----+---------+-------+
3 rows in set (0.00 sec)

mariadb> desc x$host_summary_by_file_io;
+------------+---------------+------+-----+---------+-------+
| Field      | Type          | Null | Key | Default | Extra |
+------------+---------------+------+-----+---------+-------+
| host       | varchar(60)   | YES  |     | NULL    |       |
| ios        | decimal(42,0) | YES  |     | NULL    |       |
| io_latency | decimal(42,0) | YES  |     | NULL    |       |
+------------+---------------+------+-----+---------+-------+
3 rows in set (0.06 sec)
```

##### Example

```SQL
  mariadb> select * from host_summary_by_file_io;
  +------------+-------+------------+
  | host       | ios   | io_latency |
  +------------+-------+------------+
  | hal1       | 26457 | 21.58 s    |
  | hal2       |  1189 | 394.21 ms  |
  +------------+-------+------------+
```

#### host_summary_by_file_io_type / x$host_summary_by_file_io_type

##### Description

Summarizes file IO by event type per host.

When the host found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc host_summary_by_file_io_type;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| host          | varchar(60)         | YES  |     | NULL    |       |
| event_name    | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | text                | YES  |     | NULL    |       |
| max_latency   | text                | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
5 rows in set (0.70 sec)

mariadb> desc x$host_summary_by_file_io_type;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| host          | varchar(60)         | YES  |     | NULL    |       |
| event_name    | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| max_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
5 rows in set (0.01 sec)
```

##### Example

```SQL
  mariadb> select * from host_summary_by_file_io_type;
  +------------+--------------------------------------+-------+---------------+-------------+
  | host       | event_name                           | total | total_latency | max_latency |
  +------------+--------------------------------------+-------+---------------+-------------+
  | hal1       | wait/io/file/sql/FRM                 |   871 | 168.15 ms     | 18.48 ms    |
  | hal1       | wait/io/file/innodb/innodb_data_file |   173 | 129.56 ms     | 34.09 ms    |
  | hal1       | wait/io/file/innodb/innodb_log_file  |    20 | 77.53 ms      | 60.66 ms    |
  | hal1       | wait/io/file/myisam/dfile            |    40 | 6.54 ms       | 4.58 ms     |
  | hal1       | wait/io/file/mysys/charset           |     3 | 4.79 ms       | 4.71 ms     |
  | hal1       | wait/io/file/myisam/kfile            |    67 | 4.38 ms       | 300.04 us   |
  | hal1       | wait/io/file/sql/ERRMSG              |     5 | 2.72 ms       | 1.69 ms     |
  | hal1       | wait/io/file/sql/pid                 |     3 | 266.30 us     | 185.47 us   |
  | hal1       | wait/io/file/sql/casetest            |     5 | 246.81 us     | 150.19 us   |
  | hal1       | wait/io/file/sql/global_ddl_log      |     2 | 21.24 us      | 18.59 us    |
  | hal2       | wait/io/file/sql/file_parser         |  1422 | 4.80 s        | 135.14 ms   |
  | hal2       | wait/io/file/sql/FRM                 |   865 | 85.82 ms      | 9.81 ms     |
  | hal2       | wait/io/file/myisam/kfile            |  1073 | 37.14 ms      | 15.79 ms    |
  | hal2       | wait/io/file/myisam/dfile            |  2991 | 25.53 ms      | 5.25 ms     |
  | hal2       | wait/io/file/sql/dbopt               |    20 | 1.07 ms       | 153.07 us   |
  | hal2       | wait/io/file/sql/misc                |     4 | 59.71 us      | 33.75 us    |
  | hal2       | wait/io/file/archive/data            |     1 | 13.91 us      | 13.91 us    |
  +------------+--------------------------------------+-------+---------------+-------------+
 ```

#### host_summary_by_stages / x$host_summary_by_stages

##### Description

Summarizes stages by host, ordered by host and total latency per stage.

When the host found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc host_summary_by_stages;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| host          | varchar(60)         | YES  |     | NULL    |       |
| event_name    | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | text                | YES  |     | NULL    |       |
| avg_latency   | text                | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
5 rows in set (0.06 sec)

mariadb> desc x$host_summary_by_stages;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| host          | varchar(60)         | YES  |     | NULL    |       |
| event_name    | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| avg_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
5 rows in set (0.81 sec)
```

##### Example

```SQL
  mariadb> select *  from host_summary_by_stages;
  +------+--------------------------------+-------+---------------+-------------+
  | host | event_name                     | total | total_latency | avg_latency |
  +------+--------------------------------+-------+---------------+-------------+
  | hal  | stage/sql/Opening tables       |   889 | 1.97 ms       | 2.22 us     |
  | hal  | stage/sql/Creating sort index  |     4 | 1.79 ms       | 446.30 us   |
  | hal  | stage/sql/init                 |    10 | 312.27 us     | 31.23 us    |
  | hal  | stage/sql/checking permissions |    10 | 300.62 us     | 30.06 us    |
  | hal  | stage/sql/freeing items        |     5 | 85.89 us      | 17.18 us    |
  | hal  | stage/sql/statistics           |     5 | 79.15 us      | 15.83 us    |
  | hal  | stage/sql/preparing            |     5 | 69.12 us      | 13.82 us    |
  | hal  | stage/sql/optimizing           |     5 | 53.11 us      | 10.62 us    |
  | hal  | stage/sql/Sending data         |     5 | 44.66 us      | 8.93 us     |
  | hal  | stage/sql/closing tables       |     5 | 37.54 us      | 7.51 us     |
  | hal  | stage/sql/System lock          |     5 | 34.28 us      | 6.86 us     |
  | hal  | stage/sql/query end            |     5 | 24.37 us      | 4.87 us     |
  | hal  | stage/sql/end                  |     5 | 8.60 us       | 1.72 us     |
  | hal  | stage/sql/Sorting result       |     5 | 8.33 us       | 1.67 us     |
  | hal  | stage/sql/executing            |     5 | 5.37 us       | 1.07 us     |
  | hal  | stage/sql/cleaning up          |     5 | 4.60 us       | 919.00 ns   |
  +------+--------------------------------+-------+---------------+-------------+
```

#### host_summary_by_statement_latency / x$host_summary_by_statement_latency

##### Description

Summarizes overall statement statistics by host.

When the host found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc host_summary_by_statement_latency;
+---------------+---------------+------+-----+---------+-------+
| Field         | Type          | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| host          | varchar(60)   | YES  |     | NULL    |       |
| total         | decimal(42,0) | YES  |     | NULL    |       |
| total_latency | text          | YES  |     | NULL    |       |
| max_latency   | text          | YES  |     | NULL    |       |
| lock_latency  | text          | YES  |     | NULL    |       |
| rows_sent     | decimal(42,0) | YES  |     | NULL    |       |
| rows_examined | decimal(42,0) | YES  |     | NULL    |       |
| rows_affected | decimal(42,0) | YES  |     | NULL    |       |
| full_scans    | decimal(43,0) | YES  |     | NULL    |       |
+---------------+---------------+------+-----+---------+-------+
9 rows in set (0.29 sec)

mariadb> desc x$host_summary_by_statement_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| host          | varchar(60)         | YES  |     | NULL    |       |
| total         | decimal(42,0)       | YES  |     | NULL    |       |
| total_latency | decimal(42,0)       | YES  |     | NULL    |       |
| max_latency   | bigint(20) unsigned | YES  |     | NULL    |       |
| lock_latency  | decimal(42,0)       | YES  |     | NULL    |       |
| rows_sent     | decimal(42,0)       | YES  |     | NULL    |       |
| rows_examined | decimal(42,0)       | YES  |     | NULL    |       |
| rows_affected | decimal(42,0)       | YES  |     | NULL    |       |
| full_scans    | decimal(43,0)       | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
9 rows in set (0.00 sec)
```

##### Example

```SQL
  mariadb> select * from host_summary_by_statement_latency;
  +------+-------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
  | host | total | total_latency | max_latency | lock_latency | rows_sent | rows_examined | rows_affected | full_scans |
  +------+-------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
  | hal  |  3381 | 00:02:09.13   | 1.48 s      | 1.07 s       |      1151 |         93947 |           150 |         91 |
  +------+-------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
```

#### host_summary_by_statement_type / x$host_summary_by_statement_type

##### Description

Summarizes the types of statements executed by each host.

When the host found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc host_summary_by_statement_type;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| host          | varchar(60)         | YES  |     | NULL    |       |
| statement     | varchar(128)        | YES  |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | text                | YES  |     | NULL    |       |
| max_latency   | text                | YES  |     | NULL    |       |
| lock_latency  | text                | YES  |     | NULL    |       |
| rows_sent     | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_examined | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_affected | bigint(20) unsigned | NO   |     | NULL    |       |
| full_scans    | bigint(21) unsigned | NO   |     | 0       |       |
+---------------+---------------------+------+-----+---------+-------+
10 rows in set (0.30 sec)

mariadb> desc x$host_summary_by_statement_type;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| host          | varchar(60)         | YES  |     | NULL    |       |
| statement     | varchar(128)        | YES  |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| max_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
| lock_latency  | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_sent     | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_examined | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_affected | bigint(20) unsigned | NO   |     | NULL    |       |
| full_scans    | bigint(21) unsigned | NO   |     | 0       |       |
+---------------+---------------------+------+-----+---------+-------+
10 rows in set (0.76 sec)
```

##### Example

```SQL
  mariadb> select * from host_summary_by_statement_type;
  +------+----------------------+--------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
  | host | statement            | total  | total_latency | max_latency | lock_latency | rows_sent | rows_examined | rows_affected | full_scans |
  +------+----------------------+--------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
  | hal  | create_view          |   2063 | 00:05:04.20   | 463.58 ms   | 1.42 s       |         0 |             0 |             0 |          0 |
  | hal  | select               |    174 | 40.87 s       | 28.83 s     | 858.13 ms    |      5212 |        157022 |             0 |         82 |
  | hal  | stmt                 |   6645 | 15.31 s       | 491.78 ms   | 0 ps         |         0 |             0 |          7951 |          0 |
  | hal  | call_procedure       |     17 | 4.78 s        | 1.02 s      | 37.94 ms     |         0 |             0 |            19 |          0 |
  | hal  | create_table         |     19 | 3.04 s        | 431.71 ms   | 0 ps         |         0 |             0 |             0 |          0 |
  ...
  +------+----------------------+--------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
```

#### innodb_buffer_stats_by_schema / x$innodb_buffer_stats_by_schema

##### Description

Summarizes the output of the INFORMATION_SCHEMA.INNODB_BUFFER_PAGE table, aggregating by schema.

##### Structures

```SQL
mariadb> desc innodb_buffer_stats_by_schema;
+---------------+---------------+------+-----+---------+-------+
| Field         | Type          | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| object_schema | text          | YES  |     | NULL    |       |
| allocated     | text          | YES  |     | NULL    |       |
| data          | text          | YES  |     | NULL    |       |
| pages         | bigint(21)    | NO   |     | 0       |       |
| pages_hashed  | bigint(21)    | NO   |     | 0       |       |
| pages_old     | bigint(21)    | NO   |     | 0       |       |
| rows_cached   | decimal(44,0) | YES  |     | NULL    |       |
+---------------+---------------+------+-----+---------+-------+
7 rows in set (0.08 sec)

mariadb> desc x$innodb_buffer_stats_by_schema;
+---------------+---------------+------+-----+---------+-------+
| Field         | Type          | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| object_schema | text          | YES  |     | NULL    |       |
| allocated     | decimal(43,0) | YES  |     | NULL    |       |
| data          | decimal(43,0) | YES  |     | NULL    |       |
| pages         | bigint(21)    | NO   |     | 0       |       |
| pages_hashed  | bigint(21)    | NO   |     | 0       |       |
| pages_old     | bigint(21)    | NO   |     | 0       |       |
| rows_cached   | decimal(44,0) | NO   |     | 0       |       |
+---------------+---------------+------+-----+---------+-------+
7 rows in set (0.12 sec)
````

##### Example

```SQL
mariadb> select * from innodb_buffer_stats_by_schema;
+--------------------------+------------+------------+-------+--------------+-----------+-------------+
| object_schema            | allocated  | data       | pages | pages_hashed | pages_old | rows_cached |
+--------------------------+------------+------------+-------+--------------+-----------+-------------+
| mem30_trunk__instruments | 1.69 MiB   | 510.03 KiB |   108 |          108 |       108 |        3885 |
| InnoDB System            | 688.00 KiB | 351.62 KiB |    43 |           43 |        43 |         862 |
| mem30_trunk__events      | 80.00 KiB  | 21.61 KiB  |     5 |            5 |         5 |         229 |
+--------------------------+------------+------------+-------+--------------+-----------+-------------+
```

#### innodb_buffer_stats_by_table / x$innodb_buffer_stats_by_table

##### Description

Summarizes the output of the INFORMATION_SCHEMA.INNODB_BUFFER_PAGE table, aggregating by schema and table name.

##### Structures

```SQL
mariadb> desc innodb_buffer_stats_by_table;
+---------------+---------------+------+-----+---------+-------+
| Field         | Type          | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| object_schema | text          | YES  |     | NULL    |       |
| object_name   | text          | YES  |     | NULL    |       |
| allocated     | text          | YES  |     | NULL    |       |
| data          | text          | YES  |     | NULL    |       |
| pages         | bigint(21)    | NO   |     | 0       |       |
| pages_hashed  | bigint(21)    | NO   |     | 0       |       |
| pages_old     | bigint(21)    | NO   |     | 0       |       |
| rows_cached   | decimal(44,0) | YES  |     | NULL    |       |
+---------------+---------------+------+-----+---------+-------+
8 rows in set (0.09 sec)

mariadb> desc x$innodb_buffer_stats_by_table;
+---------------+---------------+------+-----+---------+-------+
| Field         | Type          | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| object_schema | text          | YES  |     | NULL    |       |
| object_name   | text          | YES  |     | NULL    |       |
| allocated     | decimal(43,0) | YES  |     | NULL    |       |
| data          | decimal(43,0) | YES  |     | NULL    |       |
| pages         | bigint(21)    | NO   |     | 0       |       |
| pages_hashed  | bigint(21)    | NO   |     | 0       |       |
| pages_old     | bigint(21)    | NO   |     | 0       |       |
| rows_cached   | decimal(44,0) | NO   |     | 0       |       |
+---------------+---------------+------+-----+---------+-------+
8 rows in set (0.18 sec)
```

##### Example

```SQL
mariadb> select * from innodb_buffer_stats_by_table;
+--------------------------+------------------------------------+------------+-----------+-------+--------------+-----------+-------------+
| object_schema            | object_name                        | allocated  | data      | pages | pages_hashed | pages_old | rows_cached |
+--------------------------+------------------------------------+------------+-----------+-------+--------------+-----------+-------------+
| InnoDB System            | SYS_COLUMNS                        | 128.00 KiB | 98.97 KiB |     8 |            8 |         8 |        1532 |
| InnoDB System            | SYS_FOREIGN                        | 128.00 KiB | 55.48 KiB |     8 |            8 |         8 |         172 |
| InnoDB System            | SYS_TABLES                         | 128.00 KiB | 56.18 KiB |     8 |            8 |         8 |         365 |
| InnoDB System            | SYS_INDEXES                        | 112.00 KiB | 76.16 KiB |     7 |            7 |         7 |        1046 |
| mem30_trunk__instruments | agentlatencytime                   | 96.00 KiB  | 28.83 KiB |     6 |            6 |         6 |         252 |
| mem30_trunk__instruments | binlogspaceusagedata               | 96.00 KiB  | 22.54 KiB |     6 |            6 |         6 |         196 |
| mem30_trunk__instruments | connectionsdata                    | 96.00 KiB  | 36.68 KiB |     6 |            6 |         6 |         276 |
| mem30_trunk__instruments | connectionsmaxdata                 | 96.00 KiB  | 31.88 KiB |     6 |            6 |         6 |         271 |
| mem30_trunk__instruments | cpuaverage                         | 96.00 KiB  | 14.32 KiB |     6 |            6 |         6 |          55 |
| mem30_trunk__instruments | diskiototaldata                    | 96.00 KiB  | 42.71 KiB |     6 |            6 |         6 |         152 |
| mem30_trunk__instruments | innodbopenfilesdata                | 96.00 KiB  | 32.61 KiB |     6 |            6 |         6 |         266 |
| mem30_trunk__instruments | innodbrowlocktimestatisticsdata    | 96.00 KiB  | 32.16 KiB |     6 |            6 |         6 |         261 |
| mem30_trunk__instruments | myisamkeybufferusagedata           | 96.00 KiB  | 25.99 KiB |     6 |            6 |         6 |         232 |
| mem30_trunk__instruments | mysqlprocessactivity               | 96.00 KiB  | 31.99 KiB |     6 |            6 |         6 |         252 |
| mem30_trunk__instruments | querycacheaveragefreeblocksizedata | 96.00 KiB  | 27.00 KiB |     6 |            6 |         6 |         237 |
| mem30_trunk__instruments | querycacheaveragequerysizedata     | 96.00 KiB  | 38.29 KiB |     6 |            6 |         6 |         315 |
| mem30_trunk__instruments | querycachefragmentationdata        | 96.00 KiB  | 27.00 KiB |     6 |            6 |         6 |         237 |
| mem30_trunk__instruments | querycachememorydata               | 96.00 KiB  | 32.58 KiB |     6 |            6 |         6 |         278 |
| mem30_trunk__instruments | querycachequeriesincachedata       | 96.00 KiB  | 27.15 KiB |     6 |            6 |         6 |         238 |
| mem30_trunk__instruments | ramusagedata                       | 96.00 KiB  | 15.02 KiB |     6 |            6 |         6 |          59 |
| mem30_trunk__instruments | slaverelaylogspaceusagedata        | 96.00 KiB  | 28.28 KiB |     6 |            6 |         6 |         249 |
| mem30_trunk__instruments | swapusagedata                      | 96.00 KiB  | 15.02 KiB |     6 |            6 |         6 |          59 |
| InnoDB System            | SYS_FIELDS                         | 80.00 KiB  | 49.78 KiB |     5 |            5 |         5 |        1147 |
| InnoDB System            | SYS_DATAFILES                      | 32.00 KiB  | 3.97 KiB  |     2 |            2 |         2 |          60 |
| InnoDB System            | SYS_FOREIGN_COLS                   | 32.00 KiB  | 7.43 KiB  |     2 |            2 |         2 |          83 |
| InnoDB System            | SYS_TABLESPACES                    | 32.00 KiB  | 3.65 KiB  |     2 |            2 |         2 |          56 |
| InnoDB System            | SYS_IBUF_TABLE                     | 16.00 KiB  | 0 bytes   |     1 |            1 |         1 |           0 |
+--------------------------+------------------------------------+------------+-----------+-------+--------------+-----------+-------------+
```

#### innodb_lock_waits / x$innodb_lock_waits

##### Description

Gives a snapshot of which InnoDB locks transactions are waiting for.
The lock waits are ordered by the age of the lock descending.

##### Structures

```SQL
mariadb> desc sys.innodb_lock_waits;
+------------------------------+---------------------+------+-----+---------------------+-------+
| Field                        | Type                | Null | Key | Default             | Extra |
+------------------------------+---------------------+------+-----+---------------------+-------+
| wait_started                 | datetime            | YES  |     | NULL                |       |
| wait_age                     | time                | YES  |     | NULL                |       |
| wait_age_secs                | bigint(21)          | YES  |     | NULL                |       |
| locked_table                 | varchar(1024)       | NO   |     |                     |       |
| locked_index                 | varchar(1024)       | YES  |     | NULL                |       |
| locked_type                  | varchar(32)         | NO   |     |                     |       |
| waiting_trx_id               | varchar(18)         | NO   |     |                     |       |
| waiting_trx_started          | datetime            | NO   |     | 0000-00-00 00:00:00 |       |
| waiting_trx_age              | time                | YES  |     | NULL                |       |
| waiting_trx_rows_locked      | bigint(21) unsigned | NO   |     | 0                   |       |
| waiting_trx_rows_modified    | bigint(21) unsigned | NO   |     | 0                   |       |
| waiting_pid                  | bigint(21) unsigned | NO   |     | 0                   |       |
| waiting_query                | longtext            | YES  |     | NULL                |       |
| waiting_lock_id              | varchar(81)         | NO   |     |                     |       |
| waiting_lock_mode            | varchar(32)         | NO   |     |                     |       |
| blocking_trx_id              | varchar(18)         | NO   |     |                     |       |
| blocking_pid                 | bigint(21) unsigned | NO   |     | 0                   |       |
| blocking_query               | longtext            | YES  |     | NULL                |       |
| blocking_lock_id             | varchar(81)         | NO   |     |                     |       |
| blocking_lock_mode           | varchar(32)         | NO   |     |                     |       |
| blocking_trx_started         | datetime            | NO   |     | 0000-00-00 00:00:00 |       |
| blocking_trx_age             | time                | YES  |     | NULL                |       |
| blocking_trx_rows_locked     | bigint(21) unsigned | NO   |     | 0                   |       |
| blocking_trx_rows_modified   | bigint(21) unsigned | NO   |     | 0                   |       |
| sql_kill_blocking_query      | varchar(32)         | YES  |     | NULL                |       |
| sql_kill_blocking_connection | varchar(26)         | YES  |     | NULL                |       |
+------------------------------+---------------------+------+-----+---------------------+-------+
26 rows in set (0.01 sec)

mariadb> desc sys.x$innodb_lock_waits;
+------------------------------+---------------------+------+-----+---------------------+-------+
| Field                        | Type                | Null | Key | Default             | Extra |
+------------------------------+---------------------+------+-----+---------------------+-------+
| wait_started                 | datetime            | YES  |     | NULL                |       |
| wait_age                     | time                | YES  |     | NULL                |       |
| wait_age_secs                | bigint(21)          | YES  |     | NULL                |       |
| locked_table                 | varchar(1024)       | NO   |     |                     |       |
| locked_index                 | varchar(1024)       | YES  |     | NULL                |       |
| locked_type                  | varchar(32)         | NO   |     |                     |       |
| waiting_trx_id               | varchar(18)         | NO   |     |                     |       |
| waiting_trx_started          | datetime            | NO   |     | 0000-00-00 00:00:00 |       |
| waiting_trx_age              | time                | YES  |     | NULL                |       |
| waiting_trx_rows_locked      | bigint(21) unsigned | NO   |     | 0                   |       |
| waiting_trx_rows_modified    | bigint(21) unsigned | NO   |     | 0                   |       |
| waiting_pid                  | bigint(21) unsigned | NO   |     | 0                   |       |
| waiting_query                | varchar(1024)       | YES  |     | NULL                |       |
| waiting_lock_id              | varchar(81)         | NO   |     |                     |       |
| waiting_lock_mode            | varchar(32)         | NO   |     |                     |       |
| blocking_trx_id              | varchar(18)         | NO   |     |                     |       |
| blocking_pid                 | bigint(21) unsigned | NO   |     | 0                   |       |
| blocking_query               | varchar(1024)       | YES  |     | NULL                |       |
| blocking_lock_id             | varchar(81)         | NO   |     |                     |       |
| blocking_lock_mode           | varchar(32)         | NO   |     |                     |       |
| blocking_trx_started         | datetime            | NO   |     | 0000-00-00 00:00:00 |       |
| blocking_trx_age             | time                | YES  |     | NULL                |       |
| blocking_trx_rows_locked     | bigint(21) unsigned | NO   |     | 0                   |       |
| blocking_trx_rows_modified   | bigint(21) unsigned | NO   |     | 0                   |       |
| sql_kill_blocking_query      | varchar(32)         | YES  |     | NULL                |       |
| sql_kill_blocking_connection | varchar(26)         | YES  |     | NULL                |       |
+------------------------------+---------------------+------+-----+---------------------+-------+
26 rows in set (0.02 sec)
```

##### Example

```SQL
mariadb> SELECT * FROM innodb_lock_waits\G
*************************** 1. row ***************************
                wait_started: 2014-11-11 13:39:20
                    wait_age: 00:00:07
               wait_age_secs: 7
                locked_table: `db1`.`t1`
                locked_index: PRIMARY
                 locked_type: RECORD
              waiting_trx_id: 867158
         waiting_trx_started: 2014-11-11 13:39:15
             waiting_trx_age: 00:00:12
     waiting_trx_rows_locked: 0
   waiting_trx_rows_modified: 0
                 waiting_pid: 3
               waiting_query: UPDATE t1 SET val = val + 1 WHERE id = 2
             waiting_lock_id: 867158:2363:3:3
           waiting_lock_mode: X
             blocking_trx_id: 867157
                blocking_pid: 4
              blocking_query: UPDATE t1 SET val = val + 1 + SLEEP(10) WHERE id = 2
            blocking_lock_id: 867157:2363:3:3
          blocking_lock_mode: X
        blocking_trx_started: 2014-11-11 13:39:11
            blocking_trx_age: 00:00:16
    blocking_trx_rows_locked: 1
  blocking_trx_rows_modified: 1
     sql_kill_blocking_query: KILL QUERY 4
sql_kill_blocking_connection: KILL 4
```

#### io_by_thread_by_latency / x$io_by_thread_by_latency

##### Description

Shows the top IO consumers by thread, ordered by total latency.

##### Structures

```SQL
mariadb> desc io_by_thread_by_latency;
+----------------+---------------------+------+-----+---------+-------+
| Field          | Type                | Null | Key | Default | Extra |
+----------------+---------------------+------+-----+---------+-------+
| user           | varchar(128)        | YES  |     | NULL    |       |
| total          | decimal(42,0)       | YES  |     | NULL    |       |
| total_latency  | text                | YES  |     | NULL    |       |
| min_latency    | text                | YES  |     | NULL    |       |
| avg_latency    | text                | YES  |     | NULL    |       |
| max_latency    | text                | YES  |     | NULL    |       |
| thread_id      | bigint(20) unsigned | NO   |     | NULL    |       |
| processlist_id | bigint(20) unsigned | YES  |     | NULL    |       |
+----------------+---------------------+------+-----+---------+-------+
8 rows in set (0.14 sec)

mariadb> desc x$io_by_thread_by_latency;
+----------------+---------------------+------+-----+---------+-------+
| Field          | Type                | Null | Key | Default | Extra |
+----------------+---------------------+------+-----+---------+-------+
| user           | varchar(128)        | YES  |     | NULL    |       |
| total          | decimal(42,0)       | YES  |     | NULL    |       |
| total_latency  | decimal(42,0)       | YES  |     | NULL    |       |
| min_latency    | bigint(20) unsigned | YES  |     | NULL    |       |
| avg_latency    | decimal(24,4)       | YES  |     | NULL    |       |
| max_latency    | bigint(20) unsigned | YES  |     | NULL    |       |
| thread_id      | bigint(20) unsigned | NO   |     | NULL    |       |
| processlist_id | bigint(20) unsigned | YES  |     | NULL    |       |
+----------------+---------------------+------+-----+---------+-------+
8 rows in set (0.03 sec)
```

##### Example

```SQL
mariadb> select * from io_by_thread_by_latency;
+---------------------+-------+---------------+-------------+-------------+-------------+-----------+----------------+
| user                | total | total_latency | min_latency | avg_latency | max_latency | thread_id | processlist_id |
+---------------------+-------+---------------+-------------+-------------+-------------+-----------+----------------+
| root@localhost      | 11580 | 18.01 s       | 429.78 ns   | 1.12 ms     | 181.07 ms   |        25 |              6 |
| main                |  1358 | 1.31 s        | 475.02 ns   | 2.27 ms     | 350.70 ms   |         1 |           NULL |
| page_cleaner        |   654 | 147.44 ms     | 588.12 ns   | 225.44 us   | 46.41 ms    |        18 |           NULL |
| io_write_thread     |   131 | 107.75 ms     | 8.60 us     | 822.55 us   | 27.69 ms    |         8 |           NULL |
| io_write_thread     |    46 | 47.07 ms      | 10.64 us    | 1.02 ms     | 16.90 ms    |         9 |           NULL |
| io_write_thread     |    71 | 46.99 ms      | 9.11 us     | 661.81 us   | 17.04 ms    |        11 |           NULL |
| io_log_thread       |    20 | 21.01 ms      | 14.25 us    | 1.05 ms     | 7.08 ms     |         3 |           NULL |
| srv_master_thread   |    13 | 17.60 ms      | 8.49 us     | 1.35 ms     | 9.99 ms     |        16 |           NULL |
| srv_purge_thread    |     4 | 1.81 ms       | 34.31 us    | 452.45 us   | 1.02 ms     |        17 |           NULL |
| io_write_thread     |    19 | 951.39 us     | 9.75 us     | 50.07 us    | 297.47 us   |        10 |           NULL |
| signal_handler      |     3 | 218.03 us     | 21.64 us    | 72.68 us    | 154.84 us   |        19 |           NULL |
+---------------------+-------+---------------+-------------+-------------+-------------+-----------+----------------+
```

#### io_global_by_file_by_bytes / x$io_global_by_file_by_bytes

##### Description

Shows the top global IO consumers by bytes usage by file.

##### Structures

```SQL
mariadb> desc io_global_by_file_by_bytes;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| file          | varchar(512)        | YES  |     | NULL    |       |
| count_read    | bigint(20) unsigned | NO   |     | NULL    |       |
| total_read    | text                | YES  |     | NULL    |       |
| avg_read      | text                | YES  |     | NULL    |       |
| count_write   | bigint(20) unsigned | NO   |     | NULL    |       |
| total_written | text                | YES  |     | NULL    |       |
| avg_write     | text                | YES  |     | NULL    |       |
| total         | text                | YES  |     | NULL    |       |
| write_pct     | decimal(26,2)       | NO   |     | 0.00    |       |
+---------------+---------------------+------+-----+---------+-------+
9 rows in set (0.15 sec)

mariadb> desc x$io_global_by_file_by_bytes;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| file          | varchar(512)        | NO   |     | NULL    |       |
| count_read    | bigint(20) unsigned | NO   |     | NULL    |       |
| total_read    | bigint(20)          | NO   |     | NULL    |       |
| avg_read      | decimal(23,4)       | NO   |     | 0.0000  |       |
| count_write   | bigint(20) unsigned | NO   |     | NULL    |       |
| total_written | bigint(20)          | NO   |     | NULL    |       |
| avg_write     | decimal(23,4)       | NO   |     | 0.0000  |       |
| total         | bigint(21)          | NO   |     | 0       |       |
| write_pct     | decimal(26,2)       | NO   |     | 0.00    |       |
+---------------+---------------------+------+-----+---------+-------+
9 rows in set (0.14 sec)
```

##### Example

```SQL
mariadb> SELECT * FROM io_global_by_file_by_bytes LIMIT 5;
+--------------------------------------------+------------+------------+-----------+-------------+---------------+-----------+------------+-----------+
| file                                       | count_read | total_read | avg_read  | count_write | total_written | avg_write | total      | write_pct |
+--------------------------------------------+------------+------------+-----------+-------------+---------------+-----------+------------+-----------+
| @@datadir/ibdata1                          |        147 | 4.27 MiB   | 29.71 KiB |           3 | 48.00 KiB     | 16.00 KiB | 4.31 MiB   |      1.09 |
| @@datadir/mysql/proc.MYD                   |        347 | 85.35 KiB  | 252 bytes |         111 | 19.08 KiB     | 176 bytes | 104.43 KiB |     18.27 |
| @@datadir/ib_logfile0                      |          6 | 68.00 KiB  | 11.33 KiB |           8 | 4.00 KiB      | 512 bytes | 72.00 KiB  |      5.56 |
| /opt/mysql/5.5.33/share/english/errmsg.sys |          3 | 43.68 KiB  | 14.56 KiB |           0 | 0 bytes       | 0 bytes   | 43.68 KiB  |      0.00 |
| /opt/mysql/5.5.33/share/charsets/Index.xml |          1 | 17.89 KiB  | 17.89 KiB |           0 | 0 bytes       | 0 bytes   | 17.89 KiB  |      0.00 |
+--------------------------------------------+------------+------------+-----------+-------------+---------------+-----------+------------+-----------+
```

#### io_global_by_file_by_latency / x$io_global_by_file_by_latency

##### Description

Shows the top global IO consumers by latency by file.

##### Structures

```SQL
mariadb> desc io_global_by_file_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| file          | varchar(512)        | YES  |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | text                | YES  |     | NULL    |       |
| count_read    | bigint(20) unsigned | NO   |     | NULL    |       |
| read_latency  | text                | YES  |     | NULL    |       |
| count_write   | bigint(20) unsigned | NO   |     | NULL    |       |
| write_latency | text                | YES  |     | NULL    |       |
| count_misc    | bigint(20) unsigned | NO   |     | NULL    |       |
| misc_latency  | text                | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
9 rows in set (0.00 sec)

mariadb> desc x$io_global_by_file_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| file          | varchar(512)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| count_read    | bigint(20) unsigned | NO   |     | NULL    |       |
| read_latency  | bigint(20) unsigned | NO   |     | NULL    |       |
| count_write   | bigint(20) unsigned | NO   |     | NULL    |       |
| write_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| count_misc    | bigint(20) unsigned | NO   |     | NULL    |       |
| misc_latency  | bigint(20) unsigned | NO   |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
9 rows in set (0.07 sec)
```

##### Example

```SQL
mariadb> select * from io_global_by_file_by_latency limit 5;
+-----------------------------------------------------------+-------+---------------+------------+--------------+-------------+---------------+------------+--------------+
| file                                                      | total | total_latency | count_read | read_latency | count_write | write_latency | count_misc | misc_latency |
+-----------------------------------------------------------+-------+---------------+------------+--------------+-------------+---------------+------------+--------------+
| @@datadir/sys/wait_classes_global_by_avg_latency_raw.frm~ |    24 | 451.99 ms     |          0 | 0 ps         |           4 | 108.07 us     |         20 | 451.88 ms    |
| @@datadir/sys/innodb_buffer_stats_by_schema_raw.frm~      |    24 | 379.84 ms     |          0 | 0 ps         |           4 | 108.88 us     |         20 | 379.73 ms    |
| @@datadir/sys/io_by_thread_by_latency_raw.frm~            |    24 | 379.46 ms     |          0 | 0 ps         |           4 | 101.37 us     |         20 | 379.36 ms    |
| @@datadir/ibtmp1                                          |    53 | 373.45 ms     |          0 | 0 ps         |          48 | 246.08 ms     |          5 | 127.37 ms    |
| @@datadir/sys/statement_analysis_raw.frm~                 |    24 | 353.14 ms     |          0 | 0 ps         |           4 | 94.96 us      |         20 | 353.04 ms    |
+-----------------------------------------------------------+-------+---------------+------------+--------------+-------------+---------------+------------+--------------+
```

#### io_global_by_wait_by_bytes / x$io_global_by_wait_by_bytes

##### Description

Shows the top global IO consumer classes by bytes usage.

##### Structures

```SQL
mariadb> desc io_global_by_wait_by_bytes;
+-----------------+---------------------+------+-----+---------+-------+
| Field           | Type                | Null | Key | Default | Extra |
+-----------------+---------------------+------+-----+---------+-------+
| event_name      | varchar(128)        | YES  |     | NULL    |       |
| total           | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency   | text                | YES  |     | NULL    |       |
| min_latency     | text                | YES  |     | NULL    |       |
| avg_latency     | text                | YES  |     | NULL    |       |
| max_latency     | text                | YES  |     | NULL    |       |
| count_read      | bigint(20) unsigned | NO   |     | NULL    |       |
| total_read      | text                | YES  |     | NULL    |       |
| avg_read        | text                | YES  |     | NULL    |       |
| count_write     | bigint(20) unsigned | NO   |     | NULL    |       |
| total_written   | text                | YES  |     | NULL    |       |
| avg_written     | text                | YES  |     | NULL    |       |
| total_requested | text                | YES  |     | NULL    |       |
+-----------------+---------------------+------+-----+---------+-------+
13 rows in set (0.02 sec)

mariadb> desc x$io_global_by_wait_by_bytes;
+-----------------+---------------------+------+-----+---------+-------+
| Field           | Type                | Null | Key | Default | Extra |
+-----------------+---------------------+------+-----+---------+-------+
| event_name      | varchar(128)        | YES  |     | NULL    |       |
| total           | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
| min_latency     | bigint(20) unsigned | NO   |     | NULL    |       |
| avg_latency     | bigint(20) unsigned | NO   |     | NULL    |       |
| max_latency     | bigint(20) unsigned | NO   |     | NULL    |       |
| count_read      | bigint(20) unsigned | NO   |     | NULL    |       |
| total_read      | bigint(20)          | NO   |     | NULL    |       |
| avg_read        | decimal(23,4)       | NO   |     | 0.0000  |       |
| count_write     | bigint(20) unsigned | NO   |     | NULL    |       |
| total_written   | bigint(20)          | NO   |     | NULL    |       |
| avg_written     | decimal(23,4)       | NO   |     | 0.0000  |       |
| total_requested | bigint(21)          | NO   |     | 0       |       |
+-----------------+---------------------+------+-----+---------+-------+
13 rows in set (0.01 sec)
```

##### Example

```SQL
mariadb> select * from io_global_by_wait_by_bytes;
+--------------------+--------+---------------+-------------+-------------+-------------+------------+------------+-----------+-------------+---------------+-------------+-----------------+
| event_name         | total  | total_latency | min_latency | avg_latency | max_latency | count_read | total_read | avg_read  | count_write | total_written | avg_written | total_requested |
+--------------------+--------+---------------+-------------+-------------+-------------+------------+------------+-----------+-------------+---------------+-------------+-----------------+
| myisam/dfile       | 163681 | 983.13 ms     | 379.08 ns   | 6.01 us     | 22.06 ms    |      68737 | 127.31 MiB | 1.90 KiB  |     1012221 | 121.52 MiB    | 126 bytes   | 248.83 MiB      |
| myisam/kfile       |   1775 | 375.13 ms     | 1.02 us     | 211.34 µs   | 35.15 ms    |      54066 | 9.97 MiB   | 193 bytes |      428257 | 12.40 MiB     | 30 bytes    | 22.37 MiB       |
| sql/FRM            |  57889 | 8.40 s        | 19.44 ns    | 145.05 us   | 336.71 ms   |       8009 | 2.60 MiB   | 341 bytes |       14675 | 2.91 MiB      | 208 bytes   | 5.51 MiB        |
| sql/global_ddl_log |    164 | 75.96 ms      | 5.72 us     | 463.19 µs   | 7.43 ms     |         20 | 80.00 KiB  | 4.00 KiB  |          76 | 304.00 KiB    | 4.00 KiB    | 384.00 KiB      |
| sql/file_parser    |    419 | 601.37 ms     | 1.96 us     | 1.44 ms     | 37.14 ms    |         66 | 42.01 KiB  | 652 bytes |          64 | 226.98 KiB    | 3.55 KiB    | 268.99 KiB      |
| sql/binlog         |    190 | 6.79 s        | 1.56 us     | 35.76 ms    | 4.21 s      |         52 | 60.54 KiB  | 1.16 KiB  |           0 | 0 bytes       | 0 bytes     | 60.54 KiB       |
| sql/ERRMSG         |      5 | 2.03 s        | 8.61 us     | 405.40 ms   | 2.03 s      |          3 | 51.82 KiB  | 17.27 KiB |           0 | 0 bytes       | 0 bytes     | 51.82 KiB       |
| mysys/charset      |      3 | 196.52 us     | 17.61 µs    | 65.51 µs    | 137.33 µs   |          1 | 17.83 KiB  | 17.83 KiB |           0 | 0 bytes       | 0 bytes     | 17.83 KiB       |
| sql/partition      |     81 | 18.87 ms      | 888.08 ns   | 232.92 us   | 4.67 ms     |         66 | 2.75 KiB   | 43 bytes  |           8 | 288 bytes     | 36 bytes    | 3.04 KiB        |
| sql/dbopt          | 329166 | 26.95 s       | 2.06 us     | 81.89 µs    | 178.71 ms   |          0 | 0 bytes    | 0 bytes   |           9 | 585 bytes     | 65 bytes    | 585 bytes       |
| sql/relaylog       |      7 | 1.18 ms       | 838.84 ns   | 168.30 us   | 892.70 µs   |          0 | 0 bytes    | 0 bytes   |           1 | 120 bytes     | 120 bytes   | 120 bytes       |
| mysys/cnf          |      5 | 171.61 us     | 303.26 ns   | 34.32 µs    | 115.21 µs   |          3 | 56 bytes   | 19 bytes  |           0 | 0 bytes       | 0 bytes     | 56 bytes        |
| sql/pid            |      3 | 220.55 us     | 29.29 µs    | 73.52 µs    | 143.11 µs   |          0 | 0 bytes    | 0 bytes   |           1 | 5 bytes       | 5 bytes     | 5 bytes         |
| sql/casetest       |      1 | 121.19 us     | 121.19 µs   | 121.19 µs   | 121.19 µs   |          0 | 0 bytes    | 0 bytes   |           0 | 0 bytes       | 0 bytes     | 0 bytes         |
| sql/binlog_index   |      5 | 593.47 us     | 1.07 µs     | 118.69 µs   | 535.90 µs   |          0 | 0 bytes    | 0 bytes   |           0 | 0 bytes       | 0 bytes     | 0 bytes         |
| sql/misc           |     23 | 2.73 ms       | 65.14 us    | 118.50 µs   | 255.31 µs   |          0 | 0 bytes    | 0 bytes   |           0 | 0 bytes       | 0 bytes     | 0 bytes         |
+--------------------+--------+---------------+-------------+-------------+-------------+------------+------------+-----------+-------------+---------------+-------------+-----------------+
```

#### io_global_by_wait_by_latency / x$io_global_by_wait_by_latency

##### Description

Shows the top global IO consumers by latency.

##### Structures

```SQL
mariadb> desc io_global_by_wait_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| event_name    | varchar(128)        | YES  |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | text                | YES  |     | NULL    |       |
| avg_latency   | text                | YES  |     | NULL    |       |
| max_latency   | text                | YES  |     | NULL    |       |
| read_latency  | text                | YES  |     | NULL    |       |
| write_latency | text                | YES  |     | NULL    |       |
| misc_latency  | text                | YES  |     | NULL    |       |
| count_read    | bigint(20) unsigned | NO   |     | NULL    |       |
| total_read    | text                | YES  |     | NULL    |       |
| avg_read      | text                | YES  |     | NULL    |       |
| count_write   | bigint(20) unsigned | NO   |     | NULL    |       |
| total_written | text                | YES  |     | NULL    |       |
| avg_written   | text                | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
14 rows in set (0.19 sec)

mariadb> desc x$io_global_by_wait_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| event_name    | varchar(128)        | YES  |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| avg_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
| max_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
| read_latency  | bigint(20) unsigned | NO   |     | NULL    |       |
| write_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| misc_latency  | bigint(20) unsigned | NO   |     | NULL    |       |
| count_read    | bigint(20) unsigned | NO   |     | NULL    |       |
| total_read    | bigint(20)          | NO   |     | NULL    |       |
| avg_read      | decimal(23,4)       | NO   |     | 0.0000  |       |
| count_write   | bigint(20) unsigned | NO   |     | NULL    |       |
| total_written | bigint(20)          | NO   |     | NULL    |       |
| avg_written   | decimal(23,4)       | NO   |     | 0.0000  |       |
+---------------+---------------------+------+-----+---------+-------+
14 rows in set (0.01 sec)
```

##### Example

```SQL
mariadb> SELECT * FROM io_global_by_wait_by_latency;
+-------------------------+-------+---------------+-------------+-------------+--------------+---------------+--------------+------------+------------+-----------+-------------+---------------+-------------+
| event_name              | total | total_latency | avg_latency | max_latency | read_latency | write_latency | misc_latency | count_read | total_read | avg_read  | count_write | total_written | avg_written |
+-------------------------+-------+---------------+-------------+-------------+--------------+---------------+--------------+------------+------------+-----------+-------------+---------------+-------------+
| sql/file_parser         |  5433 | 30.20 s       | 5.56 ms     | 203.65 ms   | 22.08 ms     | 24.89 ms      | 30.16 s      |         24 | 6.18 KiB   | 264 bytes |         737 | 2.15 MiB      | 2.99 KiB    |
| innodb/innodb_data_file |  1344 | 1.52 s        | 1.13 ms     | 350.70 ms   | 203.82 ms    | 450.96 ms     | 868.21 ms    |        147 | 2.30 MiB   | 16.00 KiB |        1001 | 53.61 MiB     | 54.84 KiB   |
| innodb/innodb_log_file  |   828 | 893.48 ms     | 1.08 ms     | 30.11 ms    | 16.32 ms     | 705.89 ms     | 171.27 ms    |          6 | 68.00 KiB  | 11.33 KiB |         413 | 2.19 MiB      | 5.42 KiB    |
| myisam/kfile            |  7642 | 242.34 ms     | 31.71 us    | 19.27 ms    | 73.60 ms     | 23.48 ms      | 145.26 ms    |        758 | 135.63 KiB | 183 bytes |        4386 | 232.52 KiB    | 54 bytes    |
| myisam/dfile            | 12540 | 223.47 ms     | 17.82 us    | 32.50 ms    | 87.76 ms     | 16.97 ms      | 118.74 ms    |       5390 | 4.49 MiB   | 873 bytes |        1448 | 2.65 MiB      | 1.88 KiB    |
| csv/metadata            |     8 | 28.98 ms      | 3.62 ms     | 20.15 ms    | 399.27 us    | 0 ps          | 28.58 ms     |          2 | 70 bytes   | 35 bytes  |           0 | 0 bytes       | 0 bytes     |
| mysys/charset           |     3 | 24.24 ms      | 8.08 ms     | 24.15 ms    | 24.15 ms     | 0 ps          | 93.18 us     |          1 | 17.31 KiB  | 17.31 KiB |           0 | 0 bytes       | 0 bytes     |
| sql/ERRMSG              |     5 | 20.43 ms      | 4.09 ms     | 19.31 ms    | 20.32 ms     | 0 ps          | 103.20 us    |          3 | 58.97 KiB  | 19.66 KiB |           0 | 0 bytes       | 0 bytes     |
| mysys/cnf               |     5 | 11.37 ms      | 2.27 ms     | 11.28 ms    | 11.29 ms     | 0 ps          | 78.22 us     |          3 | 56 bytes   | 19 bytes  |           0 | 0 bytes       | 0 bytes     |
| sql/dbopt               |    57 | 4.04 ms       | 70.92 us    | 843.70 us   | 0 ps         | 186.43 us     | 3.86 ms      |          0 | 0 bytes    | 0 bytes   |           7 | 431 bytes     | 62 bytes    |
| csv/data                |     4 | 411.55 us     | 102.89 us   | 234.89 us   | 0 ps         | 0 ps          | 411.55 us    |          0 | 0 bytes    | 0 bytes   |           0 | 0 bytes       | 0 bytes     |
| sql/misc                |    22 | 340.38 us     | 15.47 us    | 33.77 us    | 0 ps         | 0 ps          | 340.38 us    |          0 | 0 bytes    | 0 bytes   |           0 | 0 bytes       | 0 bytes     |
| archive/data            |    39 | 277.86 us     | 7.12 us     | 16.18 us    | 0 ps         | 0 ps          | 277.86 us    |          0 | 0 bytes    | 0 bytes   |           0 | 0 bytes       | 0 bytes     |
| sql/pid                 |     3 | 218.03 us     | 72.68 us    | 154.84 us   | 0 ps         | 21.64 us      | 196.39 us    |          0 | 0 bytes    | 0 bytes   |           1 | 6 bytes       | 6 bytes     |
| sql/casetest            |     5 | 197.15 us     | 39.43 us    | 126.31 us   | 0 ps         | 0 ps          | 197.15 us    |          0 | 0 bytes    | 0 bytes   |           0 | 0 bytes       | 0 bytes     |
| sql/global_ddl_log      |     2 | 14.60 us      | 7.30 us     | 12.12 us    | 0 ps         | 0 ps          | 14.60 us     |          0 | 0 bytes    | 0 bytes   |           0 | 0 bytes       | 0 bytes     |
+-------------------------+-------+---------------+-------------+-------------+--------------+---------------+--------------+------------+------------+-----------+-------------+---------------+-------------+
```

#### latest_file_io / x$latest_file_io

##### Description

Shows the latest file IO, by file / thread.

##### Structures

```SQL
mariadb> desc latest_file_io;
+-----------+--------------+------+-----+---------+-------+
| Field     | Type         | Null | Key | Default | Extra |
+-----------+--------------+------+-----+---------+-------+
| thread    | varchar(149) | YES  |     | NULL    |       |
| file      | varchar(512) | YES  |     | NULL    |       |
| latency   | text         | YES  |     | NULL    |       |
| operation | varchar(32)  | NO   |     | NULL    |       |
| requested | text         | YES  |     | NULL    |       |
+-----------+--------------+------+-----+---------+-------+
5 rows in set (0.10 sec)

mariadb> desc x$latest_file_io;
+-----------+---------------------+------+-----+---------+-------+
| Field     | Type                | Null | Key | Default | Extra |
+-----------+---------------------+------+-----+---------+-------+
| thread    | varchar(149)        | YES  |     | NULL    |       |
| file      | varchar(512)        | YES  |     | NULL    |       |
| latency   | bigint(20) unsigned | YES  |     | NULL    |       |
| operation | varchar(32)         | NO   |     | NULL    |       |
| requested | bigint(20)          | YES  |     | NULL    |       |
+-----------+---------------------+------+-----+---------+-------+
5 rows in set (0.05 sec)
```

##### Example

```SQL
mariadb> select * from latest_file_io limit 5;
+----------------------+----------------------------------------+------------+-----------+-----------+
| thread               | file                                   | latency    | operation | requested |
+----------------------+----------------------------------------+------------+-----------+-----------+
| msandbox@localhost:1 | @@tmpdir/#sqlcf28_1_4e.MYI             | 9.26 us    | write     | 124 bytes |
| msandbox@localhost:1 | @@tmpdir/#sqlcf28_1_4e.MYI             | 4.00 us    | write     | 2 bytes   |
| msandbox@localhost:1 | @@tmpdir/#sqlcf28_1_4e.MYI             | 56.34 us   | close     | NULL      |
| msandbox@localhost:1 | @@tmpdir/#sqlcf28_1_4e.MYD             | 53.93 us   | close     | NULL      |
| msandbox@localhost:1 | @@tmpdir/#sqlcf28_1_4e.MYI             | 104.05 ms  | delete    | NULL      |
+----------------------+----------------------------------------+------------+-----------+-----------+
```

#### memory_by_host_by_current_bytes / x$memory_by_host_by_current_bytes

##### Description

Summarizes memory use by host using the Performance Schema instrumentation.

When the host found is NULL, it is assumed to be a local "background" thread.

##### Structures

```SQL
mariadb> desc memory_by_host_by_current_bytes;
+--------------------+---------------+------+-----+---------+-------+
| Field              | Type          | Null | Key | Default | Extra |
+--------------------+---------------+------+-----+---------+-------+
| host               | varchar(60)   | YES  |     | NULL    |       |
| current_count_used | decimal(41,0) | YES  |     | NULL    |       |
| current_allocated  | text          | YES  |     | NULL    |       |
| current_avg_alloc  | text          | YES  |     | NULL    |       |
| current_max_alloc  | text          | YES  |     | NULL    |       |
| total_allocated    | text          | YES  |     | NULL    |       |
+--------------------+---------------+------+-----+---------+-------+
6 rows in set (0.24 sec)

mariadb> desc x$memory_by_host_by_current_bytes;
+--------------------+---------------+------+-----+---------+-------+
| Field              | Type          | Null | Key | Default | Extra |
+--------------------+---------------+------+-----+---------+-------+
| host               | varchar(60)   | YES  |     | NULL    |       |
| current_count_used | decimal(41,0) | YES  |     | NULL    |       |
| current_allocated  | decimal(41,0) | YES  |     | NULL    |       |
| current_avg_alloc  | decimal(45,4) | NO   |     | 0.0000  |       |
| current_max_alloc  | bigint(20)    | YES  |     | NULL    |       |
| total_allocated    | decimal(42,0) | YES  |     | NULL    |       |
+--------------------+---------------+------+-----+---------+-------+
6 rows in set (0.28 sec)
```

##### Example

```SQL
mariadb> select * from memory_by_host_by_current_bytes WHERE host IS NOT NULL;
   +------------+--------------------+-------------------+-------------------+-------------------+-----------------+
   | host       | current_count_used | current_allocated | current_avg_alloc | current_max_alloc | total_allocated |
   +------------+--------------------+-------------------+-------------------+-------------------+-----------------+
   | background |               2773 | 10.84 MiB         | 4.00 KiB          | 8.00 MiB          | 30.69 MiB       |
   | localhost  |               1509 | 809.30 KiB        | 549 bytes         | 176.38 KiB        | 83.59 MiB       |
   +------------+--------------------+-------------------+-------------------+-------------------+-----------------+
```

#### memory_by_thread_by_current_bytes / x$memory_by_thread_by_current_bytes

##### Description

Summarizes memory use by user using the Performance Schema instrumentation.

The user columns shows either the background or foreground user name appropriately.

##### Structures

```SQL
mariadb> desc memory_by_thread_by_current_bytes;
+--------------------+---------------------+------+-----+---------+-------+
| Field              | Type                | Null | Key | Default | Extra |
+--------------------+---------------------+------+-----+---------+-------+
| thread_id          | bigint(20) unsigned | NO   |     | NULL    |       |
| user               | varchar(128)        | YES  |     | NULL    |       |
| current_count_used | decimal(41,0)       | YES  |     | NULL    |       |
| current_allocated  | text                | YES  |     | NULL    |       |
| current_avg_alloc  | text                | YES  |     | NULL    |       |
| current_max_alloc  | text                | YES  |     | NULL    |       |
| total_allocated    | text                | YES  |     | NULL    |       |
+--------------------+---------------------+------+-----+---------+-------+
7 rows in set (0.49 sec)

mariadb> desc x$memory_by_thread_by_current_bytes;
+--------------------+---------------------+------+-----+---------+-------+
| Field              | Type                | Null | Key | Default | Extra |
+--------------------+---------------------+------+-----+---------+-------+
| thread_id          | bigint(20) unsigned | NO   |     | NULL    |       |
| user               | varchar(128)        | YES  |     | NULL    |       |
| current_count_used | decimal(41,0)       | YES  |     | NULL    |       |
| current_allocated  | decimal(41,0)       | YES  |     | NULL    |       |
| current_avg_alloc  | decimal(45,4)       | NO   |     | 0.0000  |       |
| current_max_alloc  | bigint(20)          | YES  |     | NULL    |       |
| total_allocated    | decimal(42,0)       | YES  |     | NULL    |       |
+--------------------+---------------------+------+-----+---------+-------+
7 rows in set (0.25 sec)
```

##### Example

```SQL
mariadb> select * from sys.memory_by_thread_by_current_bytes limit 5;
+-----------+----------------+--------------------+-------------------+-------------------+-------------------+-----------------+
| thread_id | user           | current_count_used | current_allocated | current_avg_alloc | current_max_alloc | total_allocated |
+-----------+----------------+--------------------+-------------------+-------------------+-------------------+-----------------+
|         1 | sql/main       |              29333 | 166.02 MiB        | 5.80 KiB          | 131.13 MiB        | 196.00 MiB      |
|        55 | root@localhost |                175 | 1.04 MiB          | 6.09 KiB          | 350.86 KiB        | 67.37 MiB       |
|        58 | root@localhost |                236 | 368.13 KiB        | 1.56 KiB          | 312.05 KiB        | 130.34 MiB      |
|       904 | root@localhost |                 32 | 18.00 KiB         | 576 bytes         | 16.00 KiB         | 6.68 MiB        |
|       970 | root@localhost |                 12 | 16.80 KiB         | 1.40 KiB          | 16.00 KiB         | 1.20 MiB        |
+-----------+----------------+--------------------+-------------------+-------------------+-------------------+-----------------+
```

#### memory_by_user_by_current_bytes / x$memory_by_user_by_current_bytes

##### Description

Summarizes memory use by user using the Performance Schema instrumentation.

When the user found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc memory_by_user_by_current_bytes;
+--------------------+---------------+------+-----+---------+-------+
| Field              | Type          | Null | Key | Default | Extra |
+--------------------+---------------+------+-----+---------+-------+
| user               | varchar(32)   | YES  |     | NULL    |       |
| current_count_used | decimal(41,0) | YES  |     | NULL    |       |
| current_allocated  | text          | YES  |     | NULL    |       |
| current_avg_alloc  | text          | YES  |     | NULL    |       |
| current_max_alloc  | text          | YES  |     | NULL    |       |
| total_allocated    | text          | YES  |     | NULL    |       |
+--------------------+---------------+------+-----+---------+-------+
6 rows in set (0.06 sec)

mariadb> desc x$memory_by_user_by_current_bytes;
+--------------------+---------------+------+-----+---------+-------+
| Field              | Type          | Null | Key | Default | Extra |
+--------------------+---------------+------+-----+---------+-------+
| user               | varchar(32)   | YES  |     | NULL    |       |
| current_count_used | decimal(41,0) | YES  |     | NULL    |       |
| current_allocated  | decimal(41,0) | YES  |     | NULL    |       |
| current_avg_alloc  | decimal(45,4) | NO   |     | 0.0000  |       |
| current_max_alloc  | bigint(20)    | YES  |     | NULL    |       |
| total_allocated    | decimal(42,0) | YES  |     | NULL    |       |
+--------------------+---------------+------+-----+---------+-------+
6 rows in set (0.12 sec)
```

##### Example

```SQL
mariadb> select * from memory_by_user_by_current_bytes;
+------+--------------------+-------------------+-------------------+-------------------+-----------------+
| user | current_count_used | current_allocated | current_avg_alloc | current_max_alloc | total_allocated |
+------+--------------------+-------------------+-------------------+-------------------+-----------------+
| root |               1401 | 1.09 MiB          | 815 bytes         | 334.97 KiB        | 42.73 MiB       |
| mark |                201 | 496.08 KiB        | 2.47 KiB          | 334.97 KiB        | 5.50 MiB        |
+------+--------------------+-------------------+-------------------+-------------------+-----------------+
```

#### memory_global_by_current_bytes / x$memory_global_by_current_bytes

##### Description

Shows the current memory usage within the server globally broken down by allocation type.

##### Structures

```SQL
mariadb> desc memory_global_by_current_bytes;
+-------------------+--------------+------+-----+---------+-------+
| Field             | Type         | Null | Key | Default | Extra |
+-------------------+--------------+------+-----+---------+-------+
| event_name        | varchar(128) | NO   |     | NULL    |       |
| current_count     | bigint(20)   | NO   |     | NULL    |       |
| current_alloc     | text         | YES  |     | NULL    |       |
| current_avg_alloc | text         | YES  |     | NULL    |       |
| high_count        | bigint(20)   | NO   |     | NULL    |       |
| high_alloc        | text         | YES  |     | NULL    |       |
| high_avg_alloc    | text         | YES  |     | NULL    |       |
+-------------------+--------------+------+-----+---------+-------+
7 rows in set (0.08 sec)

mariadb> desc x$memory_global_by_current_bytes;
+-------------------+---------------+------+-----+---------+-------+
| Field             | Type          | Null | Key | Default | Extra |
+-------------------+---------------+------+-----+---------+-------+
| event_name        | varchar(128)  | NO   |     | NULL    |       |
| current_count     | bigint(20)    | NO   |     | NULL    |       |
| current_alloc     | bigint(20)    | NO   |     | NULL    |       |
| current_avg_alloc | decimal(23,4) | NO   |     | 0.0000  |       |
| high_count        | bigint(20)    | NO   |     | NULL    |       |
| high_alloc        | bigint(20)    | NO   |     | NULL    |       |
| high_avg_alloc    | decimal(23,4) | NO   |     | 0.0000  |       |
+-------------------+---------------+------+-----+---------+-------+
7 rows in set (0.16 sec)
```

##### Example

```SQL
mariadb> select * from memory_global_by_current_bytes;
+----------------------------------------+---------------+---------------+-------------------+------------+------------+----------------+
| event_name                             | current_count | current_alloc | current_avg_alloc | high_count | high_alloc | high_avg_alloc |
+----------------------------------------+---------------+---------------+-------------------+------------+------------+----------------+
| memory/sql/TABLE_SHARE::mem_root       |           269 | 568.21 KiB    | 2.11 KiB          |        339 | 706.04 KiB | 2.08 KiB       |
| memory/sql/TABLE                       |           214 | 366.56 KiB    | 1.71 KiB          |        245 | 481.13 KiB | 1.96 KiB       |
| memory/sql/sp_head::main_mem_root      |            32 | 334.97 KiB    | 10.47 KiB         |        421 | 9.73 MiB   | 23.66 KiB      |
| memory/sql/Filesort_buffer::sort_keys  |             1 | 255.89 KiB    | 255.89 KiB        |          1 | 256.00 KiB | 256.00 KiB     |
| memory/mysys/array_buffer              |            82 | 121.66 KiB    | 1.48 KiB          |       1124 | 852.55 KiB | 777 bytes      |
...
+----------------------------------------+---------------+---------------+-------------------+------------+------------+----------------+
```

#### memory_global_total / x$memory_global_total

##### Description

Shows the total memory usage within the server globally.

##### Structures

```SQL
mariadb> desc memory_global_total;
+-----------------+------+------+-----+---------+-------+
| Field           | Type | Null | Key | Default | Extra |
+-----------------+------+------+-----+---------+-------+
| total_allocated | text | YES  |     | NULL    |       |
+-----------------+------+------+-----+---------+-------+
1 row in set (0.07 sec)

mariadb> desc x$memory_global_total;
+-----------------+---------------+------+-----+---------+-------+
| Field           | Type          | Null | Key | Default | Extra |
+-----------------+---------------+------+-----+---------+-------+
| total_allocated | decimal(41,0) | YES  |     | NULL    |       |
+-----------------+---------------+------+-----+---------+-------+
1 row in set (0.00 sec)
```

##### Example

```SQL
mariadb> select * from memory_global_total;
+-----------------+
| total_allocated |
+-----------------+
| 458.44 MiB      |
+-----------------+
```

#### metrics

##### Description

Creates a union of the following information:

   *  performance_schema.global_status
   *  information_schema.INNODB_METRICS
   *  Performance Schema global memory usage information 
   *  Current time

It is required that performance_schema = ON, though there is no requirements to which
instruments and consumers that are enabled. See also the description of the Enabled column below.

For view has the following columns:

   * Variable_name: The name of the variable
   * Variable_value: The value of the variable
   * Type: The type of the variable. This will depend on the source, e.g. Global Status, InnoDB Metrics - ..., etc.
   * Enabled: Whether the variable is enabled or not. Possible values are 'YES', 'NO', 'PARTIAL'.
     PARTIAL is currently only supported for the memory usage variables and means some but not all of the memory/% instruments are enabled.

##### Structures

```SQL
mariadb> DESC metrics;
+----------------+--------------+------+-----+---------+-------+
| Field          | Type         | Null | Key | Default | Extra |
+----------------+--------------+------+-----+---------+-------+
| Variable_name  | varchar(193) | YES  |     | NULL    |       |
| Variable_value | text         | YES  |     | NULL    |       |
| Type           | varchar(210) | YES  |     | NULL    |       |
| Enabled        | varchar(7)   | NO   |     |         |       |
+----------------+--------------+------+-----+---------+-------+
4 rows in set (0.00 sec)

mysq> DESC metrics_56;
+----------------+--------------+------+-----+---------+-------+
| Field          | Type         | Null | Key | Default | Extra |
+----------------+--------------+------+-----+---------+-------+
| Variable_name  | varchar(193) | YES  |     | NULL    |       |
| Variable_value | text         | YES  |     | NULL    |       |
| Type           | varchar(210) | YES  |     | NULL    |       |
| Enabled        | varchar(7)   | NO   |     |         |       |
+----------------+--------------+------+-----+---------+-------+
4 rows in set (0.01 sec)
```

##### Example

```SQL
mariadb> SELECT * FROM metrics;
+-----------------------------------------------+-------------------------...+--------------------------------------+---------+
| Variable_name                                 | Variable_value          ...| Type                                 | Enabled |
+-----------------------------------------------+-------------------------...+--------------------------------------+---------+
| aborted_clients                               | 0                       ...| Global Status                        | YES     |
| aborted_connects                              | 0                       ...| Global Status                        | YES     |
| binlog_cache_disk_use                         | 0                       ...| Global Status                        | YES     |
| binlog_cache_use                              | 0                       ...| Global Status                        | YES     |
| binlog_stmt_cache_disk_use                    | 0                       ...| Global Status                        | YES     |
| binlog_stmt_cache_use                         | 0                       ...| Global Status                        | YES     |
| bytes_received                                | 217081                  ...| Global Status                        | YES     |
| bytes_sent                                    | 27257                   ...| Global Status                        | YES     |
...
| innodb_rwlock_x_os_waits                      | 0                       ...| InnoDB Metrics - server              | YES     |
| innodb_rwlock_x_spin_rounds                   | 2723                    ...| InnoDB Metrics - server              | YES     |
| innodb_rwlock_x_spin_waits                    | 1                       ...| InnoDB Metrics - server              | YES     |
| trx_active_transactions                       | 0                       ...| InnoDB Metrics - transaction         | NO      |
...
| trx_rseg_current_size                         | 0                       ...| InnoDB Metrics - transaction         | NO      |
| trx_rseg_history_len                          | 4                       ...| InnoDB Metrics - transaction         | YES     |
| trx_rw_commits                                | 0                       ...| InnoDB Metrics - transaction         | NO      |
| trx_undo_slots_cached                         | 0                       ...| InnoDB Metrics - transaction         | NO      |
| trx_undo_slots_used                           | 0                       ...| InnoDB Metrics - transaction         | NO      |
| memory_current_allocated                      | 138244216               ...| Performance Schema                   | PARTIAL |
| memory_total_allocated                        | 138244216               ...| Performance Schema                   | PARTIAL |
| NOW()                                         | 2015-05-31 13:27:50.382 ...| System Time                          | YES     |
| UNIX_TIMESTAMP()                              | 1433042870.382          ...| System Time                          | YES     |
+-----------------------------------------------+-------------------------...+--------------------------------------+---------+
412 rows in set (0.02 sec)
```

#### processlist / x$processlist

##### Description

A detailed non-blocking processlist view to replace [INFORMATION_SCHEMA. | SHOW FULL] PROCESSLIST.

Performs less locking than the legacy sources, whilst giving extra information.

The output includes both background threads and user connections by default.  See also `session` / `x$session`
for a view that contains only user session information.

##### Structures

```SQL
mariadb> desc processlist;
+------------------------+------------------------------------------+------+-----+---------+-------+
| Field                  | Type                                     | Null | Key | Default | Extra |
+------------------------+------------------------------------------+------+-----+---------+-------+
| thd_id                 | bigint(20) unsigned                      | NO   |     | NULL    |       |
| conn_id                | bigint(20) unsigned                      | YES  |     | NULL    |       |
| user                   | varchar(128)                             | YES  |     | NULL    |       |
| db                     | varchar(64)                              | YES  |     | NULL    |       |
| command                | varchar(16)                              | YES  |     | NULL    |       |
| state                  | varchar(64)                              | YES  |     | NULL    |       |
| time                   | bigint(20)                               | YES  |     | NULL    |       |
| current_statement      | longtext                                 | YES  |     | NULL    |       |
| statement_latency      | text                                     | YES  |     | NULL    |       |
| progress               | decimal(26,2)                            | YES  |     | NULL    |       |
| lock_latency           | text                                     | YES  |     | NULL    |       |
| rows_examined          | bigint(20) unsigned                      | YES  |     | NULL    |       |
| rows_sent              | bigint(20) unsigned                      | YES  |     | NULL    |       |
| rows_affected          | bigint(20) unsigned                      | YES  |     | NULL    |       |
| tmp_tables             | bigint(20) unsigned                      | YES  |     | NULL    |       |
| tmp_disk_tables        | bigint(20) unsigned                      | YES  |     | NULL    |       |
| full_scan              | varchar(3)                               | NO   |     |         |       |
| last_statement         | longtext                                 | YES  |     | NULL    |       |
| last_statement_latency | text                                     | YES  |     | NULL    |       |
| current_memory         | text                                     | YES  |     | NULL    |       |
| last_wait              | varchar(128)                             | YES  |     | NULL    |       |
| last_wait_latency      | text                                     | YES  |     | NULL    |       |
| source                 | varchar(64)                              | YES  |     | NULL    |       |
| trx_latency            | text                                     | YES  |     | NULL    |       |
| trx_state              | enum('ACTIVE','COMMITTED','ROLLED BACK') | YES  |     | NULL    |       |
| trx_autocommit         | enum('YES','NO')                         | YES  |     | NULL    |       |
| pid                    | varchar(1024)                            | YES  |     | NULL    |       |
| program_name           | varchar(1024)                            | YES  |     | NULL    |       |
+------------------------+------------------------------------------+------+-----+---------+-------+
28 rows in set (0.04 sec)

mariadb> desc x$processlist;
+------------------------+------------------------------------------+------+-----+---------+-------+
| Field                  | Type                                     | Null | Key | Default | Extra |
+------------------------+------------------------------------------+------+-----+---------+-------+
| thd_id                 | bigint(20) unsigned                      | NO   |     | NULL    |       |
| conn_id                | bigint(20) unsigned                      | YES  |     | NULL    |       |
| user                   | varchar(128)                             | YES  |     | NULL    |       |
| db                     | varchar(64)                              | YES  |     | NULL    |       |
| command                | varchar(16)                              | YES  |     | NULL    |       |
| state                  | varchar(64)                              | YES  |     | NULL    |       |
| time                   | bigint(20)                               | YES  |     | NULL    |       |
| current_statement      | longtext                                 | YES  |     | NULL    |       |
| statement_latency      | bigint(20) unsigned                      | YES  |     | NULL    |       |
| progress               | decimal(26,2)                            | YES  |     | NULL    |       |
| lock_latency           | bigint(20) unsigned                      | YES  |     | NULL    |       |
| rows_examined          | bigint(20) unsigned                      | YES  |     | NULL    |       |
| rows_sent              | bigint(20) unsigned                      | YES  |     | NULL    |       |
| rows_affected          | bigint(20) unsigned                      | YES  |     | NULL    |       |
| tmp_tables             | bigint(20) unsigned                      | YES  |     | NULL    |       |
| tmp_disk_tables        | bigint(20) unsigned                      | YES  |     | NULL    |       |
| full_scan              | varchar(3)                               | NO   |     |         |       |
| last_statement         | longtext                                 | YES  |     | NULL    |       |
| last_statement_latency | bigint(20) unsigned                      | YES  |     | NULL    |       |
| current_memory         | decimal(41,0)                            | YES  |     | NULL    |       |
| last_wait              | varchar(128)                             | YES  |     | NULL    |       |
| last_wait_latency      | varchar(20)                              | YES  |     | NULL    |       |
| source                 | varchar(64)                              | YES  |     | NULL    |       |
| trx_latency            | bigint(20) unsigned                      | YES  |     | NULL    |       |
| trx_state              | enum('ACTIVE','COMMITTED','ROLLED BACK') | YES  |     | NULL    |       |
| trx_autocommit         | enum('YES','NO')                         | YES  |     | NULL    |       |
| pid                    | varchar(1024)                            | YES  |     | NULL    |       |
| program_name           | varchar(1024)                            | YES  |     | NULL    |       |
+------------------------+------------------------------------------+------+-----+---------+-------+
28 rows in set (0.01 sec)
```

##### Example

```SQL
mariadb> select * from sys.processlist where conn_id is not null and command != 'daemon' and conn_id != connection_id()\G
*************************** 1. row ***************************
                thd_id: 44524
               conn_id: 44502
                  user: msandbox@localhost
                    db: test
               command: Query
                 state: alter table (flush)
                  time: 18
     current_statement: alter table t1 add column g int
     statement_latency: 18.45 s
              progress: 98.84
          lock_latency: 265.43 ms
         rows_examined: 0
             rows_sent: 0
         rows_affected: 0
            tmp_tables: 0
       tmp_disk_tables: 0
             full_scan: NO
        last_statement: NULL
last_statement_latency: NULL
        current_memory: 664.06 KiB
             last_wait: wait/io/file/innodb/innodb_data_file
     last_wait_latency: 1.07 us
                source: fil0fil.cc:5146
           trx_latency: NULL
             trx_state: NULL
        trx_autocommit: NULL
                   pid: 4212
          program_name: mysql
```

#### ps_check_lost_instrumentation

##### Description

Used to check whether Performance Schema is not able to monitor all runtime data - only returns variables that have lost instruments

##### Structure

```SQL
mariadb> desc ps_check_lost_instrumentation;
+----------------+---------------+------+-----+---------+-------+
| Field          | Type          | Null | Key | Default | Extra |
+----------------+---------------+------+-----+---------+-------+
| variable_name  | varchar(64)   | NO   |     |         |       |
| variable_value | varchar(1024) | YES  |     | NULL    |       |
+----------------+---------------+------+-----+---------+-------+
2 rows in set (0.09 sec)
```

##### Example

```SQL
mariadb> select * from ps_check_lost_instrumentation;
+----------------------------------------+----------------+
| variable_name                          | variable_value |
+----------------------------------------+----------------+
| Performance_schema_file_handles_lost   | 101223         |
| Performance_schema_file_instances_lost | 1231           |
+----------------------------------------+----------------+
```

#### schema_auto_increment_columns

##### Description

Present current auto_increment usage/capacity in all tables.

##### Structures

```SQL
mariadb> desc schema_auto_increment_columns;
+----------------------+------------------------+------+-----+---------+-------+
| Field                | Type                   | Null | Key | Default | Extra |
+----------------------+------------------------+------+-----+---------+-------+
| table_schema         | varchar(64)            | NO   |     |         |       |
| table_name           | varchar(64)            | NO   |     |         |       |
| column_name          | varchar(64)            | NO   |     |         |       |
| data_type            | varchar(64)            | NO   |     |         |       |
| column_type          | longtext               | NO   |     | NULL    |       |
| is_signed            | int(1)                 | NO   |     | 0       |       |
| is_unsigned          | int(1)                 | NO   |     | 0       |       |
| max_value            | bigint(21) unsigned    | YES  |     | NULL    |       |
| auto_increment       | bigint(21) unsigned    | YES  |     | NULL    |       |
| auto_increment_ratio | decimal(25,4) unsigned | YES  |     | NULL    |       |
+----------------------+------------------------+------+-----+---------+-------+
```

##### Example

```SQL
mariadb> select * from schema_auto_increment_columns limit 5;
+-------------------+-------------------+-------------+-----------+-------------+-----------+-------------+---------------------+----------------+----------------------+
| table_schema      | table_name        | column_name | data_type | column_type | is_signed | is_unsigned | max_value           | auto_increment | auto_increment_ratio |
+-------------------+-------------------+-------------+-----------+-------------+-----------+-------------+---------------------+----------------+----------------------+
| test              | t1                | i           | tinyint   | tinyint(4)  |         1 |           0 |                 127 |             34 |               0.2677 |
| mem__advisor_text | template_meta     | hib_id      | int       | int(11)     |         1 |           0 |          2147483647 |            516 |               0.0000 |
| mem__advisors     | advisor_schedules | schedule_id | int       | int(11)     |         1 |           0 |          2147483647 |            249 |               0.0000 |
| mem__advisors     | app_identity_path | hib_id      | int       | int(11)     |         1 |           0 |          2147483647 |            251 |               0.0000 |
| mem__bean_config  | plists            | id          | bigint    | bigint(20)  |         1 |           0 | 9223372036854775807 |              1 |               0.0000 |
+-------------------+-------------------+-------------+-----------+-------------+-----------+-------------+---------------------+----------------+----------------------+
```

#### schema_index_statistics / x$schema_index_statistics

##### Description

Statistics around indexes.

Ordered by the total wait time descending - top indexes are most contended.

##### Structures

```SQL
mariadb> desc schema_index_statistics;
+----------------+---------------------+------+-----+---------+-------+
| Field          | Type                | Null | Key | Default | Extra |
+----------------+---------------------+------+-----+---------+-------+
| table_schema   | varchar(64)         | YES  |     | NULL    |       |
| table_name     | varchar(64)         | YES  |     | NULL    |       |
| index_name     | varchar(64)         | YES  |     | NULL    |       |
| rows_selected  | bigint(20) unsigned | NO   |     | NULL    |       |
| select_latency | text                | YES  |     | NULL    |       |
| rows_inserted  | bigint(20) unsigned | NO   |     | NULL    |       |
| insert_latency | text                | YES  |     | NULL    |       |
| rows_updated   | bigint(20) unsigned | NO   |     | NULL    |       |
| update_latency | text                | YES  |     | NULL    |       |
| rows_deleted   | bigint(20) unsigned | NO   |     | NULL    |       |
| delete_latency | text                | YES  |     | NULL    |       |
+----------------+---------------------+------+-----+---------+-------+
11 rows in set (0.17 sec)

mariadb> desc x$schema_index_statistics;
+----------------+---------------------+------+-----+---------+-------+
| Field          | Type                | Null | Key | Default | Extra |
+----------------+---------------------+------+-----+---------+-------+
| table_schema   | varchar(64)         | YES  |     | NULL    |       |
| table_name     | varchar(64)         | YES  |     | NULL    |       |
| index_name     | varchar(64)         | YES  |     | NULL    |       |
| rows_selected  | bigint(20) unsigned | NO   |     | NULL    |       |
| select_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_inserted  | bigint(20) unsigned | NO   |     | NULL    |       |
| insert_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_updated   | bigint(20) unsigned | NO   |     | NULL    |       |
| update_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_deleted   | bigint(20) unsigned | NO   |     | NULL    |       |
| delete_latency | bigint(20) unsigned | NO   |     | NULL    |       |
+----------------+---------------------+------+-----+---------+-------+
11 rows in set (0.42 sec)
```

##### Example

```SQL
mariadb> select * from schema_index_statistics limit 5;
+------------------+-------------+------------+---------------+----------------+---------------+----------------+--------------+----------------+--------------+----------------+
| table_schema     | table_name  | index_name | rows_selected | select_latency | rows_inserted | insert_latency | rows_updated | update_latency | rows_deleted | delete_latency |
+------------------+-------------+------------+---------------+----------------+---------------+----------------+--------------+----------------+--------------+----------------+
| mem              | mysqlserver | PRIMARY    |          6208 | 108.27 ms      |             0 | 0 ps           |         5470 | 1.47 s         |            0 | 0 ps           |
| mem              | innodb      | PRIMARY    |          4666 | 76.27 ms       |             0 | 0 ps           |         4454 | 571.47 ms      |            0 | 0 ps           |
| mem              | connection  | PRIMARY    |          1064 | 20.98 ms       |             0 | 0 ps           |         1064 | 457.30 ms      |            0 | 0 ps           |
| mem              | environment | PRIMARY    |          5566 | 151.17 ms      |             0 | 0 ps           |          694 | 252.57 ms      |            0 | 0 ps           |
| mem              | querycache  | PRIMARY    |          1698 | 27.99 ms       |             0 | 0 ps           |         1698 | 371.72 ms      |            0 | 0 ps           |
+------------------+-------------+------------+---------------+----------------+---------------+----------------+--------------+----------------+--------------+----------------+
```

#### schema_object_overview

##### Description

Shows an overview of the types of objects within each schema

Note: On instances with a large numbers of objects, this could take some time to execute, and may not be recommended.

##### Structure

```SQL
mariadb> desc schema_object_overview;
+-------------+-------------+------+-----+---------+-------+
| Field       | Type        | Null | Key | Default | Extra |
+-------------+-------------+------+-----+---------+-------+
| db          | varchar(64) | NO   |     |         |       |
| object_type | varchar(64) | NO   |     |         |       |
| count       | bigint(21)  | NO   |     | 0       |       |
+-------------+-------------+------+-----+---------+-------+
3 rows in set (0.08 sec)
```

##### Example

```SQL
mariadb> select * from schema_object_overview;
+--------------------+---------------+-------+
| db                 | object_type   | count |
+--------------------+---------------+-------+
| information_schema | SYSTEM VIEW   |    60 |
| mysql              | BASE TABLE    |    31 |
| mysql              | INDEX (BTREE) |    69 |
| performance_schema | BASE TABLE    |    76 |
| sys                | BASE TABLE    |     1 |
| sys                | FUNCTION      |    12 |
| sys                | INDEX (BTREE) |     1 |
| sys                | PROCEDURE     |    22 |
| sys                | TRIGGER       |     2 |
| sys                | VIEW          |    91 |
+--------------------+---------------+-------+
10 rows in set (1.58 sec)
```

#### privileges_by_table_by_level

##### Description

-- Shows granted privileges broken down by table on which they allow access
-- and level on which they were granted:
-- - user_privileges
-- - schema_privileges
-- - table_privileges

##### Structure

```SQL
MariaDB [test]> desc sys.privileges_by_table_by_level;
+--------------+--------------+------+-----+---------+-------+
| Field        | Type         | Null | Key | Default | Extra |
+--------------+--------------+------+-----+---------+-------+
| TABLE_SCHEMA | varchar(64)  | NO   |     | NULL    |       |
| TABLE_NAME   | varchar(64)  | NO   |     | NULL    |       |
| GRANTEE      | varchar(385) | NO   |     |         |       |
| PRIVILEGE    | varchar(64)  | NO   |     |         |       |
| LEVEL        | varchar(6)   | NO   |     |         |       |
+--------------+--------------+------+-----+---------+-------+
5 rows in set (0.002 sec)
```

##### Example

```SQL
mysql> select * from sys.privileges_by_table_by_level;
+--------------+------------+--------------------+----------------+--------+
| TABLE_SCHEMA | TABLE_NAME | GRANTEE            | PRIVILEGE_TYPE | LEVEL  |
+--------------+------------+--------------------+----------------+--------+
| test         | v1         | 'oleg'@'localhost' | SELECT         | GLOBAL |
| test         | t1         | 'oleg'@'localhost' | SELECT         | GLOBAL |
| test         | v1         | 'oleg'@'localhost' | INSERT         | GLOBAL |
| test         | t1         | 'oleg'@'localhost' | INSERT         | GLOBAL |
| test         | v1         | 'oleg'@'localhost' | UPDATE         | GLOBAL |
| test         | v1         | 'PUBLIC'@''        | SELECT         | SCHEMA |
| test         | t1         | 'PUBLIC'@''        | SELECT         | SCHEMA |
| test         | v1         | 'PUBLIC'@''        | INSERT         | SCHEMA |
| test         | t1         | 'PUBLIC'@''        | INSERT         | SCHEMA |
| test         | v1         | 'PUBLIC'@''        | UPDATE         | SCHEMA |
| test         | t1         | 'PUBLIC'@''        | UPDATE         | SCHEMA |
| test         | v1         | 'PUBLIC'@''        | DELETE HISTORY | SCHEMA |
| test         | t1         | 'PUBLIC'@''        | DELETE HISTORY | SCHEMA |
| test         | t1         | 'oleg'@'%'         | SELECT         | TABLE  |
| test         | t1         | 'oleg'@'%'         | UPDATE         | TABLE  |
| test         | v1         | 'oleg'@'%'         | SELECT         | TABLE  |
+--------------+------------+--------------------+----------------+--------+
16 rows in set (1.58 sec)
```


#### schema_table_statistics / x$schema_table_statistics

##### Description

Statistics around tables.

Ordered by the total wait time descending - top tables are most contended.

Also includes the helper view (used by schema_table_statistics_with_buffer as well):

* x$ps_schema_table_statistics_io

##### Structures

```SQL
mariadb> desc schema_table_statistics;
+-------------------+---------------------+------+-----+---------+-------+
| Field             | Type                | Null | Key | Default | Extra |
+-------------------+---------------------+------+-----+---------+-------+
| table_schema      | varchar(64)         | YES  |     | NULL    |       |
| table_name        | varchar(64)         | YES  |     | NULL    |       |
| total_latency     | text                | YES  |     | NULL    |       |
| rows_fetched      | bigint(20) unsigned | NO   |     | NULL    |       |
| fetch_latency     | text                | YES  |     | NULL    |       |
| rows_inserted     | bigint(20) unsigned | NO   |     | NULL    |       |
| insert_latency    | text                | YES  |     | NULL    |       |
| rows_updated      | bigint(20) unsigned | NO   |     | NULL    |       |
| update_latency    | text                | YES  |     | NULL    |       |
| rows_deleted      | bigint(20) unsigned | NO   |     | NULL    |       |
| delete_latency    | text                | YES  |     | NULL    |       |
| io_read_requests  | decimal(42,0)       | YES  |     | NULL    |       |
| io_read           | text                | YES  |     | NULL    |       |
| io_read_latency   | text                | YES  |     | NULL    |       |
| io_write_requests | decimal(42,0)       | YES  |     | NULL    |       |
| io_write          | text                | YES  |     | NULL    |       |
| io_write_latency  | text                | YES  |     | NULL    |       |
| io_misc_requests  | decimal(42,0)       | YES  |     | NULL    |       |
| io_misc_latency   | text                | YES  |     | NULL    |       |
+-------------------+---------------------+------+-----+---------+-------+
19 rows in set (0.12 sec)

mariadb> desc x$schema_table_statistics;
+-------------------+---------------------+------+-----+---------+-------+
| Field             | Type                | Null | Key | Default | Extra |
+-------------------+---------------------+------+-----+---------+-------+
| table_schema      | varchar(64)         | YES  |     | NULL    |       |
| table_name        | varchar(64)         | YES  |     | NULL    |       |
| total_latency     | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_fetched      | bigint(20) unsigned | NO   |     | NULL    |       |
| fetch_latency     | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_inserted     | bigint(20) unsigned | NO   |     | NULL    |       |
| insert_latency    | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_updated      | bigint(20) unsigned | NO   |     | NULL    |       |
| update_latency    | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_deleted      | bigint(20) unsigned | NO   |     | NULL    |       |
| delete_latency    | bigint(20) unsigned | NO   |     | NULL    |       |
| io_read_requests  | decimal(42,0)       | YES  |     | NULL    |       |
| io_read           | decimal(41,0)       | YES  |     | NULL    |       |
| io_read_latency   | decimal(42,0)       | YES  |     | NULL    |       |
| io_write_requests | decimal(42,0)       | YES  |     | NULL    |       |
| io_write          | decimal(41,0)       | YES  |     | NULL    |       |
| io_write_latency  | decimal(42,0)       | YES  |     | NULL    |       |
| io_misc_requests  | decimal(42,0)       | YES  |     | NULL    |       |
| io_misc_latency   | decimal(42,0)       | YES  |     | NULL    |       |
+-------------------+---------------------+------+-----+---------+-------+
19 rows in set (0.13 sec)

mariadb> desc x$ps_schema_table_statistics_io;
+---------------------------+---------------+------+-----+---------+-------+
| Field                     | Type          | Null | Key | Default | Extra |
+---------------------------+---------------+------+-----+---------+-------+
| table_schema              | varchar(64)   | YES  |     | NULL    |       |
| table_name                | varchar(64)   | YES  |     | NULL    |       |
| count_read                | decimal(42,0) | YES  |     | NULL    |       |
| sum_number_of_bytes_read  | decimal(41,0) | YES  |     | NULL    |       |
| sum_timer_read            | decimal(42,0) | YES  |     | NULL    |       |
| count_write               | decimal(42,0) | YES  |     | NULL    |       |
| sum_number_of_bytes_write | decimal(41,0) | YES  |     | NULL    |       |
| sum_timer_write           | decimal(42,0) | YES  |     | NULL    |       |
| count_misc                | decimal(42,0) | YES  |     | NULL    |       |
| sum_timer_misc            | decimal(42,0) | YES  |     | NULL    |       |
+---------------------------+---------------+------+-----+---------+-------+
10 rows in set (0.10 sec)
```

##### Example

```SQL
mariadb> select * from schema_table_statistics\G
*************************** 1. row ***************************
     table_schema: sys
       table_name: sys_config
    total_latency: 0 ps
     rows_fetched: 0
    fetch_latency: 0 ps
    rows_inserted: 0
   insert_latency: 0 ps
     rows_updated: 0
   update_latency: 0 ps
     rows_deleted: 0
   delete_latency: 0 ps
 io_read_requests: 8
          io_read: 2.28 KiB
  io_read_latency: 727.32 us
io_write_requests: 0
         io_write: 0 bytes
 io_write_latency: 0 ps
 io_misc_requests: 10
  io_misc_latency: 126.88 us
```

#### schema_redundant_indexes / x$schema_flattened_keys

##### Description

Shows indexes which are made redundant (or duplicate) by other (dominant) keys.

Also includes the the helper view `x$schema_flattened_keys`.

##### Structures

```SQL
mariadb> desc sys.schema_redundant_indexes;
+----------------------------+--------------+------+-----+---------+-------+
| Field                      | Type         | Null | Key | Default | Extra |
+----------------------------+--------------+------+-----+---------+-------+
| table_schema               | varchar(64)  | NO   |     |         |       |
| table_name                 | varchar(64)  | NO   |     |         |       |
| redundant_index_name       | varchar(64)  | NO   |     |         |       |
| redundant_index_columns    | text         | YES  |     | NULL    |       |
| redundant_index_non_unique | bigint(1)    | YES  |     | NULL    |       |
| dominant_index_name        | varchar(64)  | NO   |     |         |       |
| dominant_index_columns     | text         | YES  |     | NULL    |       |
| dominant_index_non_unique  | bigint(1)    | YES  |     | NULL    |       |
| subpart_exists             | int(1)       | NO   |     | 0       |       |
| sql_drop_index             | varchar(223) | YES  |     | NULL    |       |
+----------------------------+--------------+------+-----+---------+-------+
10 rows in set (0.00 sec)

mariadb> desc sys.x$schema_flattened_keys;
+----------------+-------------+------+-----+---------+-------+
| Field          | Type        | Null | Key | Default | Extra |
+----------------+-------------+------+-----+---------+-------+
| table_schema   | varchar(64) | NO   |     |         |       |
| table_name     | varchar(64) | NO   |     |         |       |
| index_name     | varchar(64) | NO   |     |         |       |
| non_unique     | bigint(1)   | YES  |     | NULL    |       |
| subpart_exists | bigint(1)   | YES  |     | NULL    |       |
| index_columns  | text        | YES  |     | NULL    |       |
+----------------+-------------+------+-----+---------+-------+
6 rows in set (0.00 sec)
```

##### Example

```SQL
mariadb> select * from sys.schema_redundant_indexes\G
*************************** 1. row ***************************
              table_schema: test
                table_name: rkey
      redundant_index_name: j
   redundant_index_columns: j
redundant_index_non_unique: 1
       dominant_index_name: j_2
    dominant_index_columns: j,k
 dominant_index_non_unique: 1
            subpart_exists: 0
            sql_drop_index: ALTER TABLE `test`.`rkey` DROP INDEX `j`
1 row in set (0.20 sec)

mariadb> SHOW CREATE TABLE test.rkey\G
*************************** 1. row ***************************
       Table: rkey
Create Table: CREATE TABLE `rkey` (
  `i` int(11) NOT NULL,
  `j` int(11) DEFAULT NULL,
  `k` int(11) DEFAULT NULL,
  PRIMARY KEY (`i`),
  KEY `j` (`j`),
  KEY `j_2` (`j`,`k`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
1 row in set (0.06 sec)
```

#### schema_table_lock_waits / x$schema_table_lock_waits

##### Description

Shows sessions that are blocked waiting on table metadata locks, and who is blocking them.

##### Structures

```SQL
mariadb> desc schema_table_lock_waits;
+------------------------------+---------------------+------+-----+---------+-------+
| Field                        | Type                | Null | Key | Default | Extra |
+------------------------------+---------------------+------+-----+---------+-------+
| object_schema                | varchar(64)         | YES  |     | NULL    |       |
| object_name                  | varchar(64)         | YES  |     | NULL    |       |
| waiting_thread_id            | bigint(20) unsigned | NO   |     | NULL    |       |
| waiting_pid                  | bigint(20) unsigned | YES  |     | NULL    |       |
| waiting_account              | text                | YES  |     | NULL    |       |
| waiting_lock_type            | varchar(32)         | NO   |     | NULL    |       |
| waiting_lock_duration        | varchar(32)         | NO   |     | NULL    |       |
| waiting_query                | longtext            | YES  |     | NULL    |       |
| waiting_query_secs           | bigint(20)          | YES  |     | NULL    |       |
| waiting_query_rows_affected  | bigint(20) unsigned | YES  |     | NULL    |       |
| waiting_query_rows_examined  | bigint(20) unsigned | YES  |     | NULL    |       |
| blocking_thread_id           | bigint(20) unsigned | NO   |     | NULL    |       |
| blocking_pid                 | bigint(20) unsigned | YES  |     | NULL    |       |
| blocking_account             | text                | YES  |     | NULL    |       |
| blocking_lock_type           | varchar(32)         | NO   |     | NULL    |       |
| blocking_lock_duration       | varchar(32)         | NO   |     | NULL    |       |
| sql_kill_blocking_query      | varchar(31)         | YES  |     | NULL    |       |
| sql_kill_blocking_connection | varchar(25)         | YES  |     | NULL    |       |
+------------------------------+---------------------+------+-----+---------+-------+
18 rows in set (0.15 sec)

mariadb> desc x$schema_table_lock_waits;
+------------------------------+---------------------+------+-----+---------+-------+
| Field                        | Type                | Null | Key | Default | Extra |
+------------------------------+---------------------+------+-----+---------+-------+
| object_schema                | varchar(64)         | YES  |     | NULL    |       |
| object_name                  | varchar(64)         | YES  |     | NULL    |       |
| waiting_thread_id            | bigint(20) unsigned | NO   |     | NULL    |       |
| waiting_pid                  | bigint(20) unsigned | YES  |     | NULL    |       |
| waiting_account              | text                | YES  |     | NULL    |       |
| waiting_lock_type            | varchar(32)         | NO   |     | NULL    |       |
| waiting_lock_duration        | varchar(32)         | NO   |     | NULL    |       |
| waiting_query                | longtext            | YES  |     | NULL    |       |
| waiting_query_secs           | bigint(20)          | YES  |     | NULL    |       |
| waiting_query_rows_affected  | bigint(20) unsigned | YES  |     | NULL    |       |
| waiting_query_rows_examined  | bigint(20) unsigned | YES  |     | NULL    |       |
| blocking_thread_id           | bigint(20) unsigned | NO   |     | NULL    |       |
| blocking_pid                 | bigint(20) unsigned | YES  |     | NULL    |       |
| blocking_account             | text                | YES  |     | NULL    |       |
| blocking_lock_type           | varchar(32)         | NO   |     | NULL    |       |
| blocking_lock_duration       | varchar(32)         | NO   |     | NULL    |       |
| sql_kill_blocking_query      | varchar(31)         | YES  |     | NULL    |       |
| sql_kill_blocking_connection | varchar(25)         | YES  |     | NULL    |       |
+------------------------------+---------------------+------+-----+---------+-------+
18 rows in set (0.03 sec)
```

##### Example

```SQL
mariadb> select * from sys.schema_table_lock_waits\G
*************************** 1. row ***************************
               object_schema: test
                 object_name: t
           waiting_thread_id: 43
                 waiting_pid: 21
             waiting_account: msandbox@localhost
           waiting_lock_type: SHARED_UPGRADABLE
       waiting_lock_duration: TRANSACTION
               waiting_query: alter table test.t add foo int
          waiting_query_secs: 988
 waiting_query_rows_affected: 0
 waiting_query_rows_examined: 0
          blocking_thread_id: 42
                blocking_pid: 20
            blocking_account: msandbox@localhost
          blocking_lock_type: SHARED_NO_READ_WRITE
      blocking_lock_duration: TRANSACTION
     sql_kill_blocking_query: KILL QUERY 20
sql_kill_blocking_connection: KILL 20
```

#### schema_table_statistics_with_buffer / x$schema_table_statistics_with_buffer

##### Description

Statistics around tables.

Ordered by the total wait time descending - top tables are most contended.

More statistics such as caching stats for the InnoDB buffer pool with InnoDB tables

Uses the x$ps_schema_table_statistics_io helper view from schema_table_statistics.

##### Structures

```SQL
mariadb> desc schema_table_statistics_with_buffer;
+----------------------------+---------------------+------+-----+---------+-------+
| Field                      | Type                | Null | Key | Default | Extra |
+----------------------------+---------------------+------+-----+---------+-------+
| table_schema               | varchar(64)         | YES  |     | NULL    |       |
| table_name                 | varchar(64)         | YES  |     | NULL    |       |
| rows_fetched               | bigint(20) unsigned | NO   |     | NULL    |       |
| fetch_latency              | text                | YES  |     | NULL    |       |
| rows_inserted              | bigint(20) unsigned | NO   |     | NULL    |       |
| insert_latency             | text                | YES  |     | NULL    |       |
| rows_updated               | bigint(20) unsigned | NO   |     | NULL    |       |
| update_latency             | text                | YES  |     | NULL    |       |
| rows_deleted               | bigint(20) unsigned | NO   |     | NULL    |       |
| delete_latency             | text                | YES  |     | NULL    |       |
| io_read_requests           | decimal(42,0)       | YES  |     | NULL    |       |
| io_read                    | text                | YES  |     | NULL    |       |
| io_read_latency            | text                | YES  |     | NULL    |       |
| io_write_requests          | decimal(42,0)       | YES  |     | NULL    |       |
| io_write                   | text                | YES  |     | NULL    |       |
| io_write_latency           | text                | YES  |     | NULL    |       |
| io_misc_requests           | decimal(42,0)       | YES  |     | NULL    |       |
| io_misc_latency            | text                | YES  |     | NULL    |       |
| innodb_buffer_allocated    | text                | YES  |     | NULL    |       |
| innodb_buffer_data         | text                | YES  |     | NULL    |       |
| innodb_buffer_free         | text                | YES  |     | NULL    |       |
| innodb_buffer_pages        | bigint(21)          | YES  |     | 0       |       |
| innodb_buffer_pages_hashed | bigint(21)          | YES  |     | 0       |       |
| innodb_buffer_pages_old    | bigint(21)          | YES  |     | 0       |       |
| innodb_buffer_rows_cached  | decimal(44,0)       | YES  |     | 0       |       |
+----------------------------+---------------------+------+-----+---------+-------+
25 rows in set (0.05 sec)

mariadb> desc x$schema_table_statistics_with_buffer;
+----------------------------+---------------------+------+-----+---------+-------+
| Field                      | Type                | Null | Key | Default | Extra |
+----------------------------+---------------------+------+-----+---------+-------+
| table_schema               | varchar(64)         | YES  |     | NULL    |       |
| table_name                 | varchar(64)         | YES  |     | NULL    |       |
| rows_fetched               | bigint(20) unsigned | NO   |     | NULL    |       |
| fetch_latency              | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_inserted              | bigint(20) unsigned | NO   |     | NULL    |       |
| insert_latency             | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_updated               | bigint(20) unsigned | NO   |     | NULL    |       |
| update_latency             | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_deleted               | bigint(20) unsigned | NO   |     | NULL    |       |
| delete_latency             | bigint(20) unsigned | NO   |     | NULL    |       |
| io_read_requests           | decimal(42,0)       | YES  |     | NULL    |       |
| io_read                    | decimal(41,0)       | YES  |     | NULL    |       |
| io_read_latency            | decimal(42,0)       | YES  |     | NULL    |       |
| io_write_requests          | decimal(42,0)       | YES  |     | NULL    |       |
| io_write                   | decimal(41,0)       | YES  |     | NULL    |       |
| io_write_latency           | decimal(42,0)       | YES  |     | NULL    |       |
| io_misc_requests           | decimal(42,0)       | YES  |     | NULL    |       |
| io_misc_latency            | decimal(42,0)       | YES  |     | NULL    |       |
| innodb_buffer_allocated    | decimal(43,0)       | YES  |     | NULL    |       |
| innodb_buffer_data         | decimal(43,0)       | YES  |     | NULL    |       |
| innodb_buffer_free         | decimal(44,0)       | YES  |     | NULL    |       |
| innodb_buffer_pages        | bigint(21)          | YES  |     | 0       |       |
| innodb_buffer_pages_hashed | bigint(21)          | YES  |     | 0       |       |
| innodb_buffer_pages_old    | bigint(21)          | YES  |     | 0       |       |
| innodb_buffer_rows_cached  | decimal(44,0)       | YES  |     | 0       |       |
+----------------------------+---------------------+------+-----+---------+-------+
25 rows in set (0.17 sec)
```

##### Example

```SQL
mariadb> select * from schema_table_statistics_with_buffer limit 1\G
*************************** 1. row ***************************
                 table_schema: mem
                   table_name: mysqlserver
                 rows_fetched: 27087
                fetch_latency: 442.72 ms
                rows_inserted: 2
               insert_latency: 185.04 us
                 rows_updated: 5096
               update_latency: 1.39 s
                 rows_deleted: 0
               delete_latency: 0 ps
             io_read_requests: 2565
                io_read_bytes: 1121627
              io_read_latency: 10.07 ms
            io_write_requests: 1691
               io_write_bytes: 128383
             io_write_latency: 14.17 ms
             io_misc_requests: 2698
              io_misc_latency: 433.66 ms
          innodb_buffer_pages: 19
   innodb_buffer_pages_hashed: 19
      innodb_buffer_pages_old: 19
innodb_buffer_bytes_allocated: 311296
     innodb_buffer_bytes_data: 1924
    innodb_buffer_rows_cached: 2
```

#### schema_tables_with_full_table_scans / x$schema_tables_with_full_table_scans

##### Description

Finds tables that are being accessed by full table scans ordering by the number of rows scanned descending.

##### Structures

```SQL
mariadb> desc schema_tables_with_full_table_scans;
+-------------------+---------------------+------+-----+---------+-------+
| Field             | Type                | Null | Key | Default | Extra |
+-------------------+---------------------+------+-----+---------+-------+
| object_schema     | varchar(64)         | YES  |     | NULL    |       |
| object_name       | varchar(64)         | YES  |     | NULL    |       |
| rows_full_scanned | bigint(20) unsigned | NO   |     | NULL    |       |
| latency           | text                | YES  |     | NULL    |       |
+-------------------+---------------------+------+-----+---------+-------+
4 rows in set (0.02 sec)

mariadb> desc x$schema_tables_with_full_table_scans;
+-------------------+---------------------+------+-----+---------+-------+
| Field             | Type                | Null | Key | Default | Extra |
+-------------------+---------------------+------+-----+---------+-------+
| object_schema     | varchar(64)         | YES  |     | NULL    |       |
| object_name       | varchar(64)         | YES  |     | NULL    |       |
| rows_full_scanned | bigint(20) unsigned | NO   |     | NULL    |       |
| latency           | bigint(20) unsigned | NO   |     | NULL    |       |
+-------------------+---------------------+------+-----+---------+-------+
4 rows in set (0.03 sec)
```

##### Example

```SQL
mariadb> select * from schema_tables_with_full_table_scans limit 5;
+--------------------+--------------------------------+-------------------+-----------+
| object_schema      | object_name                    | rows_full_scanned | latency   |
+--------------------+--------------------------------+-------------------+-----------+
| mem30__instruments | fsstatistics                   |          10207042 | 13.10 s   |
| mem30__instruments | preparedstatementapidata       |            436428 | 973.27 ms |
| mem30__instruments | mysqlprocessactivity           |            411702 | 282.07 ms |
| mem30__instruments | querycachequeriesincachedata   |            374011 | 767.15 ms |
| mem30__instruments | rowaccessesdata                |            322321 | 1.55 s    |
+--------------------+--------------------------------+-------------------+-----------+
```

#### schema_unused_indexes

##### Description

Finds indexes that have had no events against them (and hence, no usage).

To trust whether the data from this view is representative of your workload, you should ensure that the server has been up for a representative amount of time before using it.

PRIMARY (key) indexes are ignored.

##### Structure

```SQL
mariadb> desc schema_unused_indexes;
+---------------+-------------+------+-----+---------+-------+
| Field         | Type        | Null | Key | Default | Extra |
+---------------+-------------+------+-----+---------+-------+
| object_schema | varchar(64) | YES  |     | NULL    |       |
| object_name   | varchar(64) | YES  |     | NULL    |       |
| index_name    | varchar(64) | YES  |     | NULL    |       |
+---------------+-------------+------+-----+---------+-------+
3 rows in set (0.09 sec)
```

##### Example

```SQL
mariadb> select * from schema_unused_indexes limit 5;
+--------------------+---------------------+--------------------+
| object_schema      | object_name         | index_name         |
+--------------------+---------------------+--------------------+
| mem30__bean_config | plists              | path               |
| mem30__config      | group_selections    | name               |
| mem30__config      | notification_groups | name               |
| mem30__config      | user_form_defaults  | FKC1AEF1F9E7EE2CFB |
| mem30__enterprise  | whats_new_entries   | entryId            |
+--------------------+---------------------+--------------------+
```

#### session / x$session

##### Description

A detailed non-blocking processlist view to replace [INFORMATION_SCHEMA. | SHOW FULL] PROCESSLIST.

Performs less locking than the legacy sources, whilst giving extra information.

The output of this view is restricted to threads from user sessions.  See also processlist / x$processlist which contains both user and background threads.

##### Structures

```SQL
mariadb> desc session;
+------------------------+------------------------------------------+------+-----+---------+-------+
| Field                  | Type                                     | Null | Key | Default | Extra |
+------------------------+------------------------------------------+------+-----+---------+-------+
| thd_id                 | bigint(20) unsigned                      | NO   |     | NULL    |       |
| conn_id                | bigint(20) unsigned                      | YES  |     | NULL    |       |
| user                   | varchar(128)                             | YES  |     | NULL    |       |
| db                     | varchar(64)                              | YES  |     | NULL    |       |
| command                | varchar(16)                              | YES  |     | NULL    |       |
| state                  | varchar(64)                              | YES  |     | NULL    |       |
| time                   | bigint(20)                               | YES  |     | NULL    |       |
| current_statement      | longtext                                 | YES  |     | NULL    |       |
| statement_latency      | text                                     | YES  |     | NULL    |       |
| progress               | decimal(26,2)                            | YES  |     | NULL    |       |
| lock_latency           | text                                     | YES  |     | NULL    |       |
| rows_examined          | bigint(20) unsigned                      | YES  |     | NULL    |       |
| rows_sent              | bigint(20) unsigned                      | YES  |     | NULL    |       |
| rows_affected          | bigint(20) unsigned                      | YES  |     | NULL    |       |
| tmp_tables             | bigint(20) unsigned                      | YES  |     | NULL    |       |
| tmp_disk_tables        | bigint(20) unsigned                      | YES  |     | NULL    |       |
| full_scan              | varchar(3)                               | NO   |     |         |       |
| last_statement         | longtext                                 | YES  |     | NULL    |       |
| last_statement_latency | text                                     | YES  |     | NULL    |       |
| current_memory         | text                                     | YES  |     | NULL    |       |
| last_wait              | varchar(128)                             | YES  |     | NULL    |       |
| last_wait_latency      | text                                     | YES  |     | NULL    |       |
| source                 | varchar(64)                              | YES  |     | NULL    |       |
| trx_latency            | text                                     | YES  |     | NULL    |       |
| trx_state              | enum('ACTIVE','COMMITTED','ROLLED BACK') | YES  |     | NULL    |       |
| trx_autocommit         | enum('YES','NO')                         | YES  |     | NULL    |       |
| pid                    | varchar(1024)                            | YES  |     | NULL    |       |
| program_name           | varchar(1024)                            | YES  |     | NULL    |       |
+------------------------+------------------------------------------+------+-----+---------+-------+
28 rows in set (0.00 sec)

mariadb> desc x$session;
+------------------------+------------------------------------------+------+-----+---------+-------+
| Field                  | Type                                     | Null | Key | Default | Extra |
+------------------------+------------------------------------------+------+-----+---------+-------+
| thd_id                 | bigint(20) unsigned                      | NO   |     | NULL    |       |
| conn_id                | bigint(20) unsigned                      | YES  |     | NULL    |       |
| user                   | varchar(128)                             | YES  |     | NULL    |       |
| db                     | varchar(64)                              | YES  |     | NULL    |       |
| command                | varchar(16)                              | YES  |     | NULL    |       |
| state                  | varchar(64)                              | YES  |     | NULL    |       |
| time                   | bigint(20)                               | YES  |     | NULL    |       |
| current_statement      | longtext                                 | YES  |     | NULL    |       |
| statement_latency      | bigint(20) unsigned                      | YES  |     | NULL    |       |
| progress               | decimal(26,2)                            | YES  |     | NULL    |       |
| lock_latency           | bigint(20) unsigned                      | YES  |     | NULL    |       |
| rows_examined          | bigint(20) unsigned                      | YES  |     | NULL    |       |
| rows_sent              | bigint(20) unsigned                      | YES  |     | NULL    |       |
| rows_affected          | bigint(20) unsigned                      | YES  |     | NULL    |       |
| tmp_tables             | bigint(20) unsigned                      | YES  |     | NULL    |       |
| tmp_disk_tables        | bigint(20) unsigned                      | YES  |     | NULL    |       |
| full_scan              | varchar(3)                               | NO   |     |         |       |
| last_statement         | longtext                                 | YES  |     | NULL    |       |
| last_statement_latency | bigint(20) unsigned                      | YES  |     | NULL    |       |
| current_memory         | decimal(41,0)                            | YES  |     | NULL    |       |
| last_wait              | varchar(128)                             | YES  |     | NULL    |       |
| last_wait_latency      | varchar(20)                              | YES  |     | NULL    |       |
| source                 | varchar(64)                              | YES  |     | NULL    |       |
| trx_latency            | bigint(20) unsigned                      | YES  |     | NULL    |       |
| trx_state              | enum('ACTIVE','COMMITTED','ROLLED BACK') | YES  |     | NULL    |       |
| trx_autocommit         | enum('YES','NO')                         | YES  |     | NULL    |       |
| pid                    | varchar(1024)                            | YES  |     | NULL    |       |
| program_name           | varchar(1024)                            | YES  |     | NULL    |       |
+------------------------+------------------------------------------+------+-----+---------+-------+
28 rows in set (0.00 sec)
```

##### Example

```SQL
mariadb> select * from sys.session\G
*************************** 1. row ***************************
                thd_id: 24
               conn_id: 2
                  user: root@localhost
                    db: sys
               command: Query
                 state: Sending data
                  time: 0
     current_statement: select * from sys.session
     statement_latency: 137.22 ms
              progress: NULL
          lock_latency: 33.75 ms
         rows_examined: 0
             rows_sent: 0
         rows_affected: 0
            tmp_tables: 4
       tmp_disk_tables: 1
             full_scan: YES
        last_statement: NULL
last_statement_latency: NULL
        current_memory: 3.26 MiB
             last_wait: wait/synch/mutex/innodb/file_format_max_mutex
     last_wait_latency: 64.09 ns
                source: trx0sys.cc:778
           trx_latency: 7.88 s
             trx_state: ACTIVE
        trx_autocommit: NO
                   pid: 4212
          program_name: mysql
```

#### session_ssl_status

##### Description

Shows SSL version, cipher and the count of re-used SSL sessions per connection

##### Structures

```SQL
mariadb> desc sys.session_ssl_status;
+---------------------+---------------------+------+-----+---------+-------+
| Field               | Type                | Null | Key | Default | Extra |
+---------------------+---------------------+------+-----+---------+-------+
| thread_id           | bigint(20) unsigned | NO   |     | NULL    |       |
| ssl_version         | varchar(1024)       | YES  |     | NULL    |       |
| ssl_cipher          | varchar(1024)       | YES  |     | NULL    |       |
| ssl_sessions_reused | varchar(1024)       | YES  |     | NULL    |       |
+---------------------+---------------------+------+-----+---------+-------+
4 rows in set (0.00 sec)
```

##### Example

```SQL
mariadb> select * from session_ssl_status;
+-----------+-------------+--------------------+---------------------+
| thread_id | ssl_version | ssl_cipher         | ssl_sessions_reused |
+-----------+-------------+--------------------+---------------------+
|        26 | TLSv1       | DHE-RSA-AES256-SHA | 0                   |
|        27 | TLSv1       | DHE-RSA-AES256-SHA | 0                   |
|        28 | TLSv1       | DHE-RSA-AES256-SHA | 0                   |
+-----------+-------------+--------------------+---------------------+
3 rows in set (0.00 sec)
```

#### statement_analysis / x$statement_analysis

##### Description

Lists a normalized statement view with aggregated statistics, ordered by the total execution time per normalized statement

##### Structures

```SQL
mariadb> desc statement_analysis;
+-------------------+---------------------+------+-----+---------------------+-------+
| Field             | Type                | Null | Key | Default             | Extra |
+-------------------+---------------------+------+-----+---------------------+-------+
| query             | longtext            | YES  |     | NULL                |       |
| db                | varchar(64)         | YES  |     | NULL                |       |
| full_scan         | varchar(1)          | NO   |     |                     |       |
| exec_count        | bigint(20) unsigned | NO   |     | NULL                |       |
| err_count         | bigint(20) unsigned | NO   |     | NULL                |       |
| warn_count        | bigint(20) unsigned | NO   |     | NULL                |       |
| total_latency     | text                | YES  |     | NULL                |       |
| max_latency       | text                | YES  |     | NULL                |       |
| avg_latency       | text                | YES  |     | NULL                |       |
| lock_latency      | text                | YES  |     | NULL                |       |
| rows_sent         | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_sent_avg     | decimal(21,0)       | NO   |     | 0                   |       |
| rows_examined     | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_examined_avg | decimal(21,0)       | NO   |     | 0                   |       |
| rows_affected     | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_affected_avg | decimal(21,0)       | NO   |     | 0                   |       |
| tmp_tables        | bigint(20) unsigned | NO   |     | NULL                |       |
| tmp_disk_tables   | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_sorted       | bigint(20) unsigned | NO   |     | NULL                |       |
| sort_merge_passes | bigint(20) unsigned | NO   |     | NULL                |       |
| digest            | varchar(32)         | YES  |     | NULL                |       |
| first_seen        | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen         | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
+-------------------+---------------------+------+-----+---------------------+-------+
23 rows in set (0.26 sec)

mariadb> desc x$statement_analysis;
+-------------------+---------------------+------+-----+---------------------+-------+
| Field             | Type                | Null | Key | Default             | Extra |
+-------------------+---------------------+------+-----+---------------------+-------+
| query             | longtext            | YES  |     | NULL                |       |
| db                | varchar(64)         | YES  |     | NULL                |       |
| full_scan         | varchar(1)          | NO   |     |                     |       |
| exec_count        | bigint(20) unsigned | NO   |     | NULL                |       |
| err_count         | bigint(20) unsigned | NO   |     | NULL                |       |
| warn_count        | bigint(20) unsigned | NO   |     | NULL                |       |
| total_latency     | bigint(20) unsigned | NO   |     | NULL                |       |
| max_latency       | bigint(20) unsigned | NO   |     | NULL                |       |
| avg_latency       | bigint(20) unsigned | NO   |     | NULL                |       |
| lock_latency      | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_sent         | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_sent_avg     | decimal(21,0)       | NO   |     | 0                   |       |
| rows_examined     | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_examined_avg | decimal(21,0)       | NO   |     | 0                   |       |
| rows_affected     | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_affected_avg | decimal(21,0)       | NO   |     | 0                   |       |
| tmp_tables        | bigint(20) unsigned | NO   |     | NULL                |       |
| tmp_disk_tables   | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_sorted       | bigint(20) unsigned | NO   |     | NULL                |       |
| sort_merge_passes | bigint(20) unsigned | NO   |     | NULL                |       |
| digest            | varchar(32)         | YES  |     | NULL                |       |
| first_seen        | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen         | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
+-------------------+---------------------+------+-----+---------------------+-------+
23 rows in set (0.27 sec)
```

##### Example

```SQL
mariadb> select * from statement_analysis limit 1\G
*************************** 1. row ***************************
            query: SELECT * FROM `schema_object_o ... MA` , `information_schema` ...
               db: sys
        full_scan: *
       exec_count: 2
        err_count: 0
       warn_count: 0
    total_latency: 16.75 s
      max_latency: 16.57 s
      avg_latency: 8.38 s
     lock_latency: 16.69 s
        rows_sent: 84
    rows_sent_avg: 42
    rows_examined: 20012
rows_examined_avg: 10006
    rows_affected: 0
rows_affected_avg: 0
       tmp_tables: 378
  tmp_disk_tables: 66
      rows_sorted: 168
sort_merge_passes: 0
           digest: 54f9bd520f0bbf15db0c2ed93386bec9
       first_seen: 2014-03-07 13:13:41
        last_seen: 2014-03-07 13:13:48
```

#### statements_with_errors_or_warnings / x$statements_with_errors_or_warnings

##### Description

Lists all normalized statements that have raised errors or warnings.

##### Structures

```SQL
mariadb> desc statements_with_errors_or_warnings;
+-------------+---------------------+------+-----+---------------------+-------+
| Field       | Type                | Null | Key | Default             | Extra |
+-------------+---------------------+------+-----+---------------------+-------+
| query       | longtext            | YES  |     | NULL                |       |
| db          | varchar(64)         | YES  |     | NULL                |       |
| exec_count  | bigint(20) unsigned | NO   |     | NULL                |       |
| errors      | bigint(20) unsigned | NO   |     | NULL                |       |
| error_pct   | decimal(27,4)       | NO   |     | 0.0000              |       |
| warnings    | bigint(20) unsigned | NO   |     | NULL                |       |
| warning_pct | decimal(27,4)       | NO   |     | 0.0000              |       |
| first_seen  | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen   | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| digest      | varchar(32)         | YES  |     | NULL                |       |
+-------------+---------------------+------+-----+---------------------+-------+
10 rows in set (0.55 sec)

mariadb> desc x$statements_with_errors_or_warnings;
+-------------+---------------------+------+-----+---------------------+-------+
| Field       | Type                | Null | Key | Default             | Extra |
+-------------+---------------------+------+-----+---------------------+-------+
| query       | longtext            | YES  |     | NULL                |       |
| db          | varchar(64)         | YES  |     | NULL                |       |
| exec_count  | bigint(20) unsigned | NO   |     | NULL                |       |
| errors      | bigint(20) unsigned | NO   |     | NULL                |       |
| error_pct   | decimal(27,4)       | NO   |     | 0.0000              |       |
| warnings    | bigint(20) unsigned | NO   |     | NULL                |       |
| warning_pct | decimal(27,4)       | NO   |     | 0.0000              |       |
| first_seen  | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen   | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| digest      | varchar(32)         | YES  |     | NULL                |       |
+-------------+---------------------+------+-----+---------------------+-------+
10 rows in set (0.25 sec)
```

##### Example

```SQL
mariadb> select * from statements_with_errors_or_warnings LIMIT 1\G
*************************** 1. row ***************************
      query: CREATE OR REPLACE ALGORITHM =  ... _delete` AS `rows_deleted` ...
         db: sys
 exec_count: 2
     errors: 1
  error_pct: 50.0000
   warnings: 0
warning_pct: 0.0000
 first_seen: 2014-03-07 12:56:54
  last_seen: 2014-03-07 13:01:01
     digest: 943a788859e623d5f7798ba0ae0fd8a9
```

#### statements_with_full_table_scans / x$statements_with_full_table_scans

##### Description

Lists all normalized statements that use have done a full table scan ordered by number the percentage of times a full scan was done, then by the statement latency.

This view ignores SHOW statements, as these always cause a full table scan, and there is nothing that can be done about this.

##### Structures

```SQL
mariadb> desc statements_with_full_table_scans;
+--------------------------+------------------------+------+-----+---------------------+-------+
| Field                    | Type                   | Null | Key | Default             | Extra |
+--------------------------+------------------------+------+-----+---------------------+-------+
| query                    | longtext               | YES  |     | NULL                |       |
| db                       | varchar(64)            | YES  |     | NULL                |       |
| exec_count               | bigint(20) unsigned    | NO   |     | NULL                |       |
| total_latency            | text                   | YES  |     | NULL                |       |
| no_index_used_count      | bigint(20) unsigned    | NO   |     | NULL                |       |
| no_good_index_used_count | bigint(20) unsigned    | NO   |     | NULL                |       |
| no_index_used_pct        | decimal(24,0)          | NO   |     | 0                   |       |
| rows_sent                | bigint(20) unsigned    | NO   |     | NULL                |       |
| rows_examined            | bigint(20) unsigned    | NO   |     | NULL                |       |
| rows_sent_avg            | decimal(21,0) unsigned | YES  |     | NULL                |       |
| rows_examined_avg        | decimal(21,0) unsigned | YES  |     | NULL                |       |
| first_seen               | timestamp              | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen                | timestamp              | NO   |     | 0000-00-00 00:00:00 |       |
| digest                   | varchar(32)            | YES  |     | NULL                |       |
+--------------------------+------------------------+------+-----+---------------------+-------+
14 rows in set (0.04 sec)

mariadb> desc x$statements_with_full_table_scans;
+--------------------------+------------------------+------+-----+---------------------+-------+
| Field                    | Type                   | Null | Key | Default             | Extra |
+--------------------------+------------------------+------+-----+---------------------+-------+
| query                    | longtext               | YES  |     | NULL                |       |
| db                       | varchar(64)            | YES  |     | NULL                |       |
| exec_count               | bigint(20) unsigned    | NO   |     | NULL                |       |
| total_latency            | bigint(20) unsigned    | NO   |     | NULL                |       |
| no_index_used_count      | bigint(20) unsigned    | NO   |     | NULL                |       |
| no_good_index_used_count | bigint(20) unsigned    | NO   |     | NULL                |       |
| no_index_used_pct        | decimal(24,0)          | NO   |     | 0                   |       |
| rows_sent                | bigint(20) unsigned    | NO   |     | NULL                |       |
| rows_examined            | bigint(20) unsigned    | NO   |     | NULL                |       |
| rows_sent_avg            | decimal(21,0) unsigned | YES  |     | NULL                |       |
| rows_examined_avg        | decimal(21,0) unsigned | YES  |     | NULL                |       |
| first_seen               | timestamp              | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen                | timestamp              | NO   |     | 0000-00-00 00:00:00 |       |
| digest                   | varchar(32)            | YES  |     | NULL                |       |
+--------------------------+------------------------+------+-----+---------------------+-------+
14 rows in set (0.14 sec)
```

##### Example

```SQL
mariadb> select * from statements_with_full_table_scans limit 1\G
*************************** 1. row ***************************
                   query: SELECT * FROM `schema_tables_w ... ex_usage` . `COUNT_READ` DESC
                      db: sys
              exec_count: 1
           total_latency: 88.20 ms
     no_index_used_count: 1
no_good_index_used_count: 0
       no_index_used_pct: 100
               rows_sent: 0
           rows_examined: 1501
           rows_sent_avg: 0
       rows_examined_avg: 1501
              first_seen: 2014-03-07 13:58:20
               last_seen: 2014-03-07 13:58:20
                  digest: 64baecd5c1e1e1651a6b92e55442a288
```

#### statements_with_runtimes_in_95th_percentile / x$statements_with_runtimes_in_95th_percentile

##### Description

Lists all statements whose average runtime, in microseconds, is in the top 95th percentile.

Also includes two helper views:

* x$ps_digest_avg_latency_distribution
* x$ps_digest_95th_percentile_by_avg_us

##### Structures

```SQL
mariadb> desc statements_with_runtimes_in_95th_percentile;
+-------------------+---------------------+------+-----+---------------------+-------+
| Field             | Type                | Null | Key | Default             | Extra |
+-------------------+---------------------+------+-----+---------------------+-------+
| query             | longtext            | YES  |     | NULL                |       |
| db                | varchar(64)         | YES  |     | NULL                |       |
| full_scan         | varchar(1)          | NO   |     |                     |       |
| exec_count        | bigint(20) unsigned | NO   |     | NULL                |       |
| err_count         | bigint(20) unsigned | NO   |     | NULL                |       |
| warn_count        | bigint(20) unsigned | NO   |     | NULL                |       |
| total_latency     | text                | YES  |     | NULL                |       |
| max_latency       | text                | YES  |     | NULL                |       |
| avg_latency       | text                | YES  |     | NULL                |       |
| rows_sent         | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_sent_avg     | decimal(21,0)       | NO   |     | 0                   |       |
| rows_examined     | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_examined_avg | decimal(21,0)       | NO   |     | 0                   |       |
| first_seen        | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen         | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| digest            | varchar(32)         | YES  |     | NULL                |       |
+-------------------+---------------------+------+-----+---------------------+-------+
16 rows in set (0.11 sec)

mariadb> desc x$statements_with_runtimes_in_95th_percentile;
+-------------------+---------------------+------+-----+---------------------+-------+
| Field             | Type                | Null | Key | Default             | Extra |
+-------------------+---------------------+------+-----+---------------------+-------+
| query             | longtext            | YES  |     | NULL                |       |
| db                | varchar(64)         | YES  |     | NULL                |       |
| full_scan         | varchar(1)          | NO   |     |                     |       |
| exec_count        | bigint(20) unsigned | NO   |     | NULL                |       |
| err_count         | bigint(20) unsigned | NO   |     | NULL                |       |
| warn_count        | bigint(20) unsigned | NO   |     | NULL                |       |
| total_latency     | bigint(20) unsigned | NO   |     | NULL                |       |
| max_latency       | bigint(20) unsigned | NO   |     | NULL                |       |
| avg_latency       | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_sent         | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_sent_avg     | decimal(21,0)       | NO   |     | 0                   |       |
| rows_examined     | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_examined_avg | decimal(21,0)       | NO   |     | 0                   |       |
| first_seen        | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen         | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| digest            | varchar(32)         | YES  |     | NULL                |       |
+-------------------+---------------------+------+-----+---------------------+-------+
16 rows in set (0.00 sec)

mariadb> desc x$ps_digest_avg_latency_distribution;
+--------+---------------+------+-----+---------+-------+
| Field  | Type          | Null | Key | Default | Extra |
+--------+---------------+------+-----+---------+-------+
| cnt    | bigint(21)    | NO   |     | 0       |       |
| avg_us | decimal(21,0) | YES  |     | NULL    |       |
+--------+---------------+------+-----+---------+-------+
2 rows in set (0.10 sec)

mariadb> desc x$ps_digest_95th_percentile_by_avg_us;
+------------+---------------+------+-----+---------+-------+
| Field      | Type          | Null | Key | Default | Extra |
+------------+---------------+------+-----+---------+-------+
| avg_us     | decimal(21,0) | YES  |     | NULL    |       |
| percentile | decimal(46,4) | NO   |     | 0.0000  |       |
+------------+---------------+------+-----+---------+-------+
2 rows in set (0.15 sec)
```

##### Example

```SQL
mariadb> select * from statements_with_runtimes_in_95th_percentile\G
*************************** 1. row ***************************
            query: SELECT * FROM `schema_object_o ... MA` , `information_schema` ...
               db: sys
        full_scan: *
       exec_count: 2
        err_count: 0
       warn_count: 0
    total_latency: 16.75 s
      max_latency: 16.57 s
      avg_latency: 8.38 s
        rows_sent: 84
    rows_sent_avg: 42
    rows_examined: 20012
rows_examined_avg: 10006
       first_seen: 2014-03-07 13:13:41
        last_seen: 2014-03-07 13:13:48
           digest: 54f9bd520f0bbf15db0c2ed93386bec9
```

#### statements_with_sorting / x$statements_with_sorting

##### Description

Lists all normalized statements that have done sorts, ordered by total_latency descending.

##### Structures

```SQL
mariadb> desc statements_with_sorting;
+-------------------+---------------------+------+-----+---------------------+-------+
| Field             | Type                | Null | Key | Default             | Extra |
+-------------------+---------------------+------+-----+---------------------+-------+
| query             | longtext            | YES  |     | NULL                |       |
| db                | varchar(64)         | YES  |     | NULL                |       |
| exec_count        | bigint(20) unsigned | NO   |     | NULL                |       |
| total_latency     | text                | YES  |     | NULL                |       |
| sort_merge_passes | bigint(20) unsigned | NO   |     | NULL                |       |
| avg_sort_merges   | decimal(21,0)       | NO   |     | 0                   |       |
| sorts_using_scans | bigint(20) unsigned | NO   |     | NULL                |       |
| sort_using_range  | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_sorted       | bigint(20) unsigned | NO   |     | NULL                |       |
| avg_rows_sorted   | decimal(21,0)       | NO   |     | 0                   |       |
| first_seen        | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen         | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| digest            | varchar(32)         | YES  |     | NULL                |       |
+-------------------+---------------------+------+-----+---------------------+-------+
13 rows in set (0.01 sec)

mariadb> desc x$statements_with_sorting;
+-------------------+---------------------+------+-----+---------------------+-------+
| Field             | Type                | Null | Key | Default             | Extra |
+-------------------+---------------------+------+-----+---------------------+-------+
| query             | longtext            | YES  |     | NULL                |       |
| db                | varchar(64)         | YES  |     | NULL                |       |
| exec_count        | bigint(20) unsigned | NO   |     | NULL                |       |
| total_latency     | bigint(20) unsigned | NO   |     | NULL                |       |
| sort_merge_passes | bigint(20) unsigned | NO   |     | NULL                |       |
| avg_sort_merges   | decimal(21,0)       | NO   |     | 0                   |       |
| sorts_using_scans | bigint(20) unsigned | NO   |     | NULL                |       |
| sort_using_range  | bigint(20) unsigned | NO   |     | NULL                |       |
| rows_sorted       | bigint(20) unsigned | NO   |     | NULL                |       |
| avg_rows_sorted   | decimal(21,0)       | NO   |     | 0                   |       |
| first_seen        | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen         | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| digest            | varchar(32)         | YES  |     | NULL                |       |
+-------------------+---------------------+------+-----+---------------------+-------+
13 rows in set (0.04 sec)
```

##### Example

```SQL
mariadb> select * from statements_with_sorting limit 1\G
*************************** 1. row ***************************
            query: SELECT * FROM `schema_object_o ... MA` , `information_schema` ...
               db: sys
       exec_count: 2
    total_latency: 16.75 s
sort_merge_passes: 0
  avg_sort_merges: 0
sorts_using_scans: 12
 sort_using_range: 0
      rows_sorted: 168
  avg_rows_sorted: 84
       first_seen: 2014-03-07 13:13:41
        last_seen: 2014-03-07 13:13:48
           digest: 54f9bd520f0bbf15db0c2ed93386bec9
```

#### statements_with_temp_tables / x$statements_with_temp_tables

##### Description

Lists all normalized statements that use temporary tables ordered by number of on disk temporary tables descending first, then by the number of memory tables.

##### Structures

```SQL
mariadb> desc statements_with_temp_tables;
+--------------------------+---------------------+------+-----+---------------------+-------+
| Field                    | Type                | Null | Key | Default             | Extra |
+--------------------------+---------------------+------+-----+---------------------+-------+
| query                    | longtext            | YES  |     | NULL                |       |
| db                       | varchar(64)         | YES  |     | NULL                |       |
| exec_count               | bigint(20) unsigned | NO   |     | NULL                |       |
| total_latency            | text                | YES  |     | NULL                |       |
| memory_tmp_tables        | bigint(20) unsigned | NO   |     | NULL                |       |
| disk_tmp_tables          | bigint(20) unsigned | NO   |     | NULL                |       |
| avg_tmp_tables_per_query | decimal(21,0)       | NO   |     | 0                   |       |
| tmp_tables_to_disk_pct   | decimal(24,0)       | NO   |     | 0                   |       |
| first_seen               | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen                | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| digest                   | varchar(32)         | YES  |     | NULL                |       |
+--------------------------+---------------------+------+-----+---------------------+-------+
11 rows in set (0.30 sec)

mariadb> desc x$statements_with_temp_tables;
+--------------------------+---------------------+------+-----+---------------------+-------+
| Field                    | Type                | Null | Key | Default             | Extra |
+--------------------------+---------------------+------+-----+---------------------+-------+
| query                    | longtext            | YES  |     | NULL                |       |
| db                       | varchar(64)         | YES  |     | NULL                |       |
| exec_count               | bigint(20) unsigned | NO   |     | NULL                |       |
| total_latency            | bigint(20) unsigned | NO   |     | NULL                |       |
| memory_tmp_tables        | bigint(20) unsigned | NO   |     | NULL                |       |
| disk_tmp_tables          | bigint(20) unsigned | NO   |     | NULL                |       |
| avg_tmp_tables_per_query | decimal(21,0)       | NO   |     | 0                   |       |
| tmp_tables_to_disk_pct   | decimal(24,0)       | NO   |     | 0                   |       |
| first_seen               | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| last_seen                | timestamp           | NO   |     | 0000-00-00 00:00:00 |       |
| digest                   | varchar(32)         | YES  |     | NULL                |       |
+--------------------------+---------------------+------+-----+---------------------+-------+
11 rows in set (0.05 sec)
```

##### Example

```SQL
mariadb> select * from statements_with_temp_tables limit 1\G
*************************** 1. row ***************************
                   query: SELECT * FROM `schema_object_o ... MA` , `information_schema` ...
                      db: sys
              exec_count: 2
           total_latency: 16.75 s
       memory_tmp_tables: 378
         disk_tmp_tables: 66
avg_tmp_tables_per_query: 189
  tmp_tables_to_disk_pct: 17
              first_seen: 2014-03-07 13:13:41
               last_seen: 2014-03-07 13:13:48
                  digest: 54f9bd520f0bbf15db0c2ed93386bec9
```

#### user_summary / x$user_summary

##### Description

Summarizes statement activity, file IO and connections by user.

When the user found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc user_summary;
+------------------------+---------------+------+-----+---------+-------+
| Field                  | Type          | Null | Key | Default | Extra |
+------------------------+---------------+------+-----+---------+-------+
| user                   | varchar(32)   | YES  |     | NULL    |       |
| statements             | decimal(64,0) | YES  |     | NULL    |       |
| statement_latency      | text          | YES  |     | NULL    |       |
| statement_avg_latency  | text          | YES  |     | NULL    |       |
| table_scans            | decimal(65,0) | YES  |     | NULL    |       |
| file_ios               | decimal(64,0) | YES  |     | NULL    |       |
| file_io_latency        | text          | YES  |     | NULL    |       |
| current_connections    | decimal(41,0) | YES  |     | NULL    |       |
| total_connections      | decimal(41,0) | YES  |     | NULL    |       |
| unique_hosts           | bigint(21)    | NO   |     | 0       |       |
| current_memory         | text          | YES  |     | NULL    |       |
| total_memory_allocated | text          | YES  |     | NULL    |       |
+------------------------+---------------+------+-----+---------+-------+
12 rows in set (0.00 sec)

mariadb> desc x$user_summary;
+------------------------+---------------+------+-----+---------+-------+
| Field                  | Type          | Null | Key | Default | Extra |
+------------------------+---------------+------+-----+---------+-------+
| user                   | varchar(32)   | YES  |     | NULL    |       |
| statements             | decimal(64,0) | YES  |     | NULL    |       |
| statement_latency      | decimal(64,0) | YES  |     | NULL    |       |
| statement_avg_latency  | decimal(65,4) | NO   |     | 0.0000  |       |
| table_scans            | decimal(65,0) | YES  |     | NULL    |       |
| file_ios               | decimal(64,0) | YES  |     | NULL    |       |
| file_io_latency        | decimal(64,0) | YES  |     | NULL    |       |
| current_connections    | decimal(41,0) | YES  |     | NULL    |       |
| total_connections      | decimal(41,0) | YES  |     | NULL    |       |
| unique_hosts           | bigint(21)    | NO   |     | 0       |       |
| current_memory         | decimal(63,0) | YES  |     | NULL    |       |
| total_memory_allocated | decimal(64,0) | YES  |     | NULL    |       |
+------------------------+---------------+------+-----+---------+-------+
12 rows in set (0.01 sec)
```

##### Example

```SQL
mariadb> select * from user_summary\G
*************************** 1. row ***************************
                  user: root
            statements: 4981
     statement_latency: 26.54 s
 statement_avg_latency: 5.33 ms
           table_scans: 74
              file_ios: 7792
       file_io_latency: 40.08 s
   current_connections: 1
     total_connections: 2
          unique_hosts: 1
        current_memory: 3.57 MiB
total_memory_allocated: 83.37 MiB
*************************** 2. row ***************************
                  user: background
            statements: 0
     statement_latency: 0 ps
 statement_avg_latency: 0 ps
           table_scans: 0
              file_ios: 1618
       file_io_latency: 4.78 s
   current_connections: 21
     total_connections: 23
          unique_hosts: 0
        current_memory: 165.94 MiB
total_memory_allocated: 197.29 MiB
```

#### user_summary_by_file_io / x$user_summary_by_file_io

##### Description

Summarizes file IO totals per user.

When the user found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc user_summary_by_file_io;
+------------+---------------+------+-----+---------+-------+
| Field      | Type          | Null | Key | Default | Extra |
+------------+---------------+------+-----+---------+-------+
| user       | varchar(32)   | YES  |     | NULL    |       |
| ios        | decimal(42,0) | YES  |     | NULL    |       |
| io_latency | text          | YES  |     | NULL    |       |
+------------+---------------+------+-----+---------+-------+
3 rows in set (0.20 sec)

mariadb> desc x$user_summary_by_file_io;
+------------+---------------+------+-----+---------+-------+
| Field      | Type          | Null | Key | Default | Extra |
+------------+---------------+------+-----+---------+-------+
| user       | varchar(32)   | YES  |     | NULL    |       |
| ios        | decimal(42,0) | YES  |     | NULL    |       |
| io_latency | decimal(42,0) | YES  |     | NULL    |       |
+------------+---------------+------+-----+---------+-------+
3 rows in set (0.02 sec)
```

##### Example

```SQL
mariadb> select * from user_summary_by_file_io;
+------------+-------+------------+
| user       | ios   | io_latency |
+------------+-------+------------+
| root       | 26457 | 21.58 s    |
| background |  1189 | 394.21 ms  |
+------------+-------+------------+
```

#### user_summary_by_file_io_type / x$user_summary_by_file_io_type

##### Description

Summarizes file IO by event type per user.

When the user found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc user_summary_by_file_io_type;
+-------------+---------------------+------+-----+---------+-------+
| Field       | Type                | Null | Key | Default | Extra |
+-------------+---------------------+------+-----+---------+-------+
| user        | varchar(32)         | YES  |     | NULL    |       |
| event_name  | varchar(128)        | NO   |     | NULL    |       |
| total       | bigint(20) unsigned | NO   |     | NULL    |       |
| latency     | text                | YES  |     | NULL    |       |
| max_latency | text                | YES  |     | NULL    |       |
+-------------+---------------------+------+-----+---------+-------+
5 rows in set (0.02 sec)

mariadb> desc x$user_summary_by_file_io_type;
+-------------+---------------------+------+-----+---------+-------+
| Field       | Type                | Null | Key | Default | Extra |
+-------------+---------------------+------+-----+---------+-------+
| user        | varchar(32)         | YES  |     | NULL    |       |
| event_name  | varchar(128)        | NO   |     | NULL    |       |
| total       | bigint(20) unsigned | NO   |     | NULL    |       |
| latency     | bigint(20) unsigned | NO   |     | NULL    |       |
| max_latency | bigint(20) unsigned | NO   |     | NULL    |       |
+-------------+---------------------+------+-----+---------+-------+
5 rows in set (0.00 sec)
```

##### Example

```SQL
mariadb> select * from user_summary_by_file_io_type;
+------------+--------------------------------------+-------+-----------+-------------+
| user       | event_name                           | total | latency   | max_latency |
+------------+--------------------------------------+-------+-----------+-------------+
| background | wait/io/file/innodb/innodb_data_file |  1434 | 3.29 s    | 147.56 ms   |
| background | wait/io/file/sql/FRM                 |   910 | 286.61 ms | 32.92 ms    |
| background | wait/io/file/sql/relaylog            |     9 | 252.28 ms | 144.17 ms   |
| background | wait/io/file/sql/binlog              |    56 | 193.73 ms | 153.72 ms   |
| background | wait/io/file/sql/binlog_index        |    22 | 183.02 ms | 81.83 ms    |
| background | wait/io/file/innodb/innodb_log_file  |    20 | 117.17 ms | 36.53 ms    |
| background | wait/io/file/sql/relaylog_index      |     9 | 50.15 ms  | 48.04 ms    |
| background | wait/io/file/sql/ERRMSG              |     5 | 35.41 ms  | 31.78 ms    |
| background | wait/io/file/myisam/kfile            |    67 | 18.14 ms  | 9.00 ms     |
| background | wait/io/file/mysys/charset           |     3 | 7.46 ms   | 4.13 ms     |
| background | wait/io/file/sql/casetest            |     5 | 6.01 ms   | 5.86 ms     |
| background | wait/io/file/sql/pid                 |     3 | 5.96 ms   | 3.06 ms     |
| background | wait/io/file/myisam/dfile            |    43 | 980.38 us | 152.46 us   |
| background | wait/io/file/mysys/cnf               |     5 | 154.97 us | 58.87 us    |
| background | wait/io/file/sql/global_ddl_log      |     2 | 18.64 us  | 16.40 us    |
| root       | wait/io/file/sql/file_parser         | 11048 | 48.79 s   | 201.11 ms   |
| root       | wait/io/file/innodb/innodb_data_file |  4699 | 3.02 s    | 46.93 ms    |
| root       | wait/io/file/sql/FRM                 | 10403 | 2.38 s    | 61.72 ms    |
| root       | wait/io/file/myisam/dfile            | 22143 | 726.77 ms | 308.79 ms   |
| root       | wait/io/file/myisam/kfile            |  6213 | 435.35 ms | 88.76 ms    |
| root       | wait/io/file/sql/dbopt               |   159 | 130.86 ms | 15.46 ms    |
| root       | wait/io/file/csv/metadata            |     8 | 86.60 ms  | 50.32 ms    |
| root       | wait/io/file/sql/binlog              |    15 | 38.79 ms  | 9.40 ms     |
| root       | wait/io/file/sql/misc                |    21 | 22.33 ms  | 15.30 ms    |
| root       | wait/io/file/csv/data                |     4 | 297.46 us | 111.93 us   |
| root       | wait/io/file/archive/data            |     3 | 54.10 us  | 40.74 us    |
+------------+--------------------------------------+-------+-----------+-------------+
```

#### user_summary_by_stages / x$user_summary_by_stages

##### Description

Summarizes stages by user, ordered by user and total latency per stage.

When the user found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc user_summary_by_stages;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| user          | varchar(32)         | YES  |     | NULL    |       |
| event_name    | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | text                | YES  |     | NULL    |       |
| avg_latency   | text                | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
5 rows in set (0.01 sec)

mariadb> desc x$user_summary_by_stages;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| user          | varchar(16)         | YES  |     | NULL    |       |
| event_name    | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| avg_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
5 rows in set (0.05 sec)
```

##### Example

```SQL
mariadb> select * from user_summary_by_stages;
+------+--------------------------------+-------+---------------+-------------+
| user | event_name                     | total | total_latency | avg_latency |
+------+--------------------------------+-------+---------------+-------------+
| root | stage/sql/Opening tables       |   889 | 1.97 ms       | 2.22 us     |
| root | stage/sql/Creating sort index  |     4 | 1.79 ms       | 446.30 us   |
| root | stage/sql/init                 |    10 | 312.27 us     | 31.23 us    |
| root | stage/sql/checking permissions |    10 | 300.62 us     | 30.06 us    |
| root | stage/sql/freeing items        |     5 | 85.89 us      | 17.18 us    |
| root | stage/sql/statistics           |     5 | 79.15 us      | 15.83 us    |
| root | stage/sql/preparing            |     5 | 69.12 us      | 13.82 us    |
| root | stage/sql/optimizing           |     5 | 53.11 us      | 10.62 us    |
| root | stage/sql/Sending data         |     5 | 44.66 us      | 8.93 us     |
| root | stage/sql/closing tables       |     5 | 37.54 us      | 7.51 us     |
| root | stage/sql/System lock          |     5 | 34.28 us      | 6.86 us     |
| root | stage/sql/query end            |     5 | 24.37 us      | 4.87 us     |
| root | stage/sql/end                  |     5 | 8.60 us       | 1.72 us     |
| root | stage/sql/Sorting result       |     5 | 8.33 us       | 1.67 us     |
| root | stage/sql/executing            |     5 | 5.37 us       | 1.07 us     |
| root | stage/sql/cleaning up          |     5 | 4.60 us       | 919.00 ns   |
+------+--------------------------------+-------+---------------+-------------+
```

#### user_summary_by_statement_latency / x$user_summary_by_statement_latency

##### Description

Summarizes overall statement statistics by user.

When the user found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc user_summary_by_statement_latency;
+---------------+---------------+------+-----+---------+-------+
| Field         | Type          | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| user          | varchar(32)   | YES  |     | NULL    |       |
| total         | decimal(42,0) | YES  |     | NULL    |       |
| total_latency | text          | YES  |     | NULL    |       |
| max_latency   | text          | YES  |     | NULL    |       |
| lock_latency  | text          | YES  |     | NULL    |       |
| rows_sent     | decimal(42,0) | YES  |     | NULL    |       |
| rows_examined | decimal(42,0) | YES  |     | NULL    |       |
| rows_affected | decimal(42,0) | YES  |     | NULL    |       |
| full_scans    | decimal(43,0) | YES  |     | NULL    |       |
+---------------+---------------+------+-----+---------+-------+
9 rows in set (0.00 sec)

mariadb> desc x$user_summary_by_statement_latency;
+---------------+---------------+------+-----+---------+-------+
| Field         | Type          | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| user          | varchar(32)   | YES  |     | NULL    |       |
| total         | decimal(42,0) | YES  |     | NULL    |       |
| total_latency | decimal(42,0) | YES  |     | NULL    |       |
| max_latency   | decimal(42,0) | YES  |     | NULL    |       |
| lock_latency  | decimal(42,0) | YES  |     | NULL    |       |
| rows_sent     | decimal(42,0) | YES  |     | NULL    |       |
| rows_examined | decimal(42,0) | YES  |     | NULL    |       |
| rows_affected | decimal(42,0) | YES  |     | NULL    |       |
| full_scans    | decimal(43,0) | YES  |     | NULL    |       |
+---------------+---------------+------+-----+---------+-------+
9 rows in set (0.28 sec)
```

##### Example

```SQL
mariadb> select * from user_summary_by_statement_latency;
+------+-------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
| user | total | total_latency | max_latency | lock_latency | rows_sent | rows_examined | rows_affected | full_scans |
+------+-------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
| root |  3381 | 00:02:09.13   | 1.48 s      | 1.07 s       |      1151 |         93947 |           150 |         91 |
+------+-------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
```

#### user_summary_by_statement_type / x$user_summary_by_statement_type

##### Description

Summarizes the types of statements executed by each user.

When the user found is NULL, it is assumed to be a "background" thread.

##### Structures

```SQL
mariadb> desc user_summary_by_statement_type;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| user          | varchar(32)         | YES  |     | NULL    |       |
| statement     | varchar(128)        | YES  |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | text                | YES  |     | NULL    |       |
| max_latency   | text                | YES  |     | NULL    |       |
| lock_latency  | text                | YES  |     | NULL    |       |
| rows_sent     | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_examined | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_affected | bigint(20) unsigned | NO   |     | NULL    |       |
| full_scans    | bigint(21) unsigned | NO   |     | 0       |       |
+---------------+---------------------+------+-----+---------+-------+
10 rows in set (0.21 sec)

mariadb> desc x$user_summary_by_statement_type;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| user          | varchar(32)         | YES  |     | NULL    |       |
| statement     | varchar(128)        | YES  |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| max_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
| lock_latency  | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_sent     | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_examined | bigint(20) unsigned | NO   |     | NULL    |       |
| rows_affected | bigint(20) unsigned | NO   |     | NULL    |       |
| full_scans    | bigint(21) unsigned | NO   |     | 0       |       |
+---------------+---------------------+------+-----+---------+-------+
10 rows in set (0.37 sec)
```

##### Example

```SQL
mariadb> select * from user_summary_by_statement_type;
+------+------------------+-------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
| user | statement        | total | total_latency | max_latency | lock_latency | rows_sent | rows_examined | rows_affected | full_scans |
+------+------------------+-------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
| root | create_view      |  1332 | 00:03:39.08   | 677.76 ms   | 494.56 ms    |         0 |             0 |             0 |          0 |
| root | select           |    88 | 20.13 s       | 16.57 s     | 17.40 s      |      1804 |         77285 |             0 |         48 |
| root | drop_db          |    16 | 6.83 s        | 1.14 s      | 5.73 s       |         0 |             0 |           953 |          0 |
| root | drop_view        |   392 | 1.70 s        | 739.49 ms   | 0 ps         |         0 |             0 |             0 |          0 |
| root | show_databases   |    16 | 1.37 s        | 587.44 ms   | 1.31 ms      |       400 |           400 |             0 |         16 |
| root | show_tables      |    34 | 676.78 ms     | 167.04 ms   | 3.46 ms      |      1087 |          1087 |             0 |         34 |
| root | create_db        |    22 | 334.90 ms     | 38.93 ms    | 0 ps         |         0 |             0 |            22 |          0 |
| root | create_procedure |   352 | 250.02 ms     | 21.90 ms    | 165.17 ms    |         0 |             0 |             0 |          0 |
| root | drop_function    |   176 | 122.44 ms     | 69.18 ms    | 87.24 ms     |         0 |             0 |             0 |          0 |
| root | create_function  |   176 | 76.12 ms      | 1.36 ms     | 49.50 ms     |         0 |             0 |             0 |          0 |
| root | drop_procedure   |   352 | 67.41 ms      | 1.57 ms     | 36.22 ms     |         0 |             0 |             0 |          0 |
| root | update           |     2 | 41.75 ms      | 35.96 ms    | 35.52 ms     |         0 |           557 |           338 |          0 |
| root | error            |     3 | 17.22 ms      | 17.05 ms    | 0 ps         |         0 |             0 |             0 |          0 |
| root | set_option       |    88 | 8.02 ms       | 1.63 ms     | 0 ps         |         0 |             0 |             0 |          0 |
| root | call_procedure   |     2 | 2.98 ms       | 2.29 ms     | 95.00 us     |         0 |             0 |             0 |          0 |
| root | Init DB          |    22 | 1.07 ms       | 117.65 us   | 0 ps         |         0 |             0 |             0 |          0 |
| root | show_status      |     1 | 408.69 us     | 408.69 us   | 102.00 us    |        23 |            23 |             0 |          1 |
+------+------------------+-------+---------------+-------------+--------------+-----------+---------------+---------------+------------+
```

#### wait_classes_global_by_avg_latency / x$wait_classes_global_by_avg_latency

##### Description

Lists the top wait classes by average latency, ignoring idle (this may be very large).

##### Structures

```SQL
mariadb> desc wait_classes_global_by_avg_latency;
+---------------+---------------+------+-----+---------+-------+
| Field         | Type          | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| event_class   | varchar(128)  | YES  |     | NULL    |       |
| total         | decimal(42,0) | YES  |     | NULL    |       |
| total_latency | text          | YES  |     | NULL    |       |
| min_latency   | text          | YES  |     | NULL    |       |
| avg_latency   | text          | YES  |     | NULL    |       |
| max_latency   | text          | YES  |     | NULL    |       |
+---------------+---------------+------+-----+---------+-------+
6 rows in set (0.11 sec)

mariadb> desc x$wait_classes_global_by_avg_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| event_class   | varchar(128)        | YES  |     | NULL    |       |
| total         | decimal(42,0)       | YES  |     | NULL    |       |
| total_latency | decimal(42,0)       | YES  |     | NULL    |       |
| min_latency   | bigint(20) unsigned | YES  |     | NULL    |       |
| avg_latency   | decimal(46,4)       | NO   |     | 0.0000  |       |
| max_latency   | bigint(20) unsigned | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
6 rows in set (0.02 sec)
```

##### Example

```SQL
mariadb> select * from wait_classes_global_by_avg_latency where event_class != 'idle';
+-------------------+--------+---------------+-------------+-------------+-------------+
| event_class       | total  | total_latency | min_latency | avg_latency | max_latency |
+-------------------+--------+---------------+-------------+-------------+-------------+
| wait/io/file      | 543123 | 44.60 s       | 19.44 ns    | 82.11 us    | 4.21 s      |
| wait/io/table     |  22002 | 766.60 ms     | 148.72 ns   | 34.84 us    | 44.97 ms    |
| wait/io/socket    |  79613 | 967.17 ms     | 0 ps        | 12.15 us    | 27.10 ms    |
| wait/lock/table   |  35409 | 18.68 ms      | 65.45 ns    | 527.51 ns   | 969.88 us   |
| wait/synch/rwlock |  37935 | 4.61 ms       | 21.38 ns    | 121.61 ns   | 34.65 us    |
| wait/synch/mutex  | 390622 | 18.60 ms      | 19.44 ns    | 47.61 ns    | 10.32 us    |
+-------------------+--------+---------------+-------------+-------------+-------------+
```

#### wait_classes_global_by_latency / x$wait_classes_global_by_latency

##### Description

Lists the top wait classes by total latency, ignoring idle (this may be very large).

##### Structures

```SQL
mariadb> desc wait_classes_global_by_latency;
+---------------+---------------+------+-----+---------+-------+
| Field         | Type          | Null | Key | Default | Extra |
+---------------+---------------+------+-----+---------+-------+
| event_class   | varchar(128)  | YES  |     | NULL    |       |
| total         | decimal(42,0) | YES  |     | NULL    |       |
| total_latency | text          | YES  |     | NULL    |       |
| min_latency   | text          | YES  |     | NULL    |       |
| avg_latency   | text          | YES  |     | NULL    |       |
| max_latency   | text          | YES  |     | NULL    |       |
+---------------+---------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

mariadb> desc x$wait_classes_global_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| event_class   | varchar(128)        | YES  |     | NULL    |       |
| total         | decimal(42,0)       | YES  |     | NULL    |       |
| total_latency | decimal(42,0)       | YES  |     | NULL    |       |
| min_latency   | bigint(20) unsigned | YES  |     | NULL    |       |
| avg_latency   | decimal(46,4)       | NO   |     | 0.0000  |       |
| max_latency   | bigint(20) unsigned | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
6 rows in set (0.02 sec)
```

##### Example

```SQL
mariadb> select * from wait_classes_global_by_latency;
+-------------------+--------+---------------+-------------+-------------+-------------+
| event_class       | total  | total_latency | min_latency | avg_latency | max_latency |
+-------------------+--------+---------------+-------------+-------------+-------------+
| wait/io/file      | 550470 | 46.01 s       | 19.44 ns    | 83.58 us    | 4.21 s      |
| wait/io/socket    | 228833 | 2.71 s        | 0 ps        | 11.86 us    | 29.93 ms    |
| wait/io/table     |  64063 | 1.89 s        | 99.79 ns    | 29.43 us    | 68.07 ms    |
| wait/lock/table   |  76029 | 47.19 ms      | 65.45 ns    | 620.74 ns   | 969.88 us   |
| wait/synch/mutex  | 635925 | 34.93 ms      | 19.44 ns    | 54.93 ns    | 107.70 us   |
| wait/synch/rwlock |  61287 | 7.62 ms       | 21.38 ns    | 124.37 ns   | 34.65 us    |
+-------------------+--------+---------------+-------------+-------------+-------------+
```

#### waits_by_user_by_latency / x$waits_by_user_by_latency

##### Description

Lists the top wait events per user by their total latency, ignoring idle (this may be very large) per user.

##### Structures

```SQL
mariadb> desc waits_by_user_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| user          | varchar(32)         | YES  |     | NULL    |       |
| event         | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | text                | YES  |     | NULL    |       |
| avg_latency   | text                | YES  |     | NULL    |       |
| max_latency   | text                | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
6 rows in set (0.00 sec)

mariadb> desc x$waits_by_user_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| user          | varchar(32)         | YES  |     | NULL    |       |
| event         | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| avg_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
| max_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
6 rows in set (0.30 sec)
```

##### Example

```SQL
mariadb> select * from waits_by_user_by_latency;
+------+-----------------------------------------------------+--------+---------------+-------------+-------------+
| user | event                                               | total  | total_latency | avg_latency | max_latency |
+------+-----------------------------------------------------+--------+---------------+-------------+-------------+
| root | wait/io/file/sql/file_parser                        |  13743 | 00:01:00.46   | 4.40 ms     | 231.88 ms   |
| root | wait/io/file/innodb/innodb_data_file                |   4699 | 3.02 s        | 643.38 us   | 46.93 ms    |
| root | wait/io/file/sql/FRM                                |  11462 | 2.60 s        | 226.83 us   | 61.72 ms    |
| root | wait/io/file/myisam/dfile                           |  26776 | 746.70 ms     | 27.89 us    | 308.79 ms   |
| root | wait/io/file/myisam/kfile                           |   7126 | 462.66 ms     | 64.93 us    | 88.76 ms    |
| root | wait/io/file/sql/dbopt                              |    179 | 137.58 ms     | 768.59 us   | 15.46 ms    |
| root | wait/io/file/csv/metadata                           |      8 | 86.60 ms      | 10.82 ms    | 50.32 ms    |
| root | wait/synch/mutex/mysys/IO_CACHE::append_buffer_lock | 798080 | 66.46 ms      | 82.94 ns    | 161.03 us   |
| root | wait/io/file/sql/binlog                             |     19 | 49.11 ms      | 2.58 ms     | 9.40 ms     |
| root | wait/io/file/sql/misc                               |     26 | 22.38 ms      | 860.80 us   | 15.30 ms    |
| root | wait/io/file/csv/data                               |      4 | 297.46 us     | 74.37 us    | 111.93 us   |
| root | wait/synch/rwlock/sql/MDL_lock::rwlock              |    944 | 287.86 us     | 304.62 ns   | 874.64 ns   |
| root | wait/io/file/archive/data                           |      4 | 82.71 us      | 20.68 us    | 40.74 us    |
| root | wait/synch/mutex/myisam/MYISAM_SHARE::intern_lock   |     60 | 12.21 us      | 203.20 ns   | 512.72 ns   |
| root | wait/synch/mutex/innodb/trx_mutex                   |     81 | 5.93 us       | 73.14 ns    | 252.59 ns   |
+------+-----------------------------------------------------+--------+---------------+-------------+-------------+
```

#### waits_by_host_by_latency / x$waits_by_host_by_latency

##### Description

Lists the top wait events per host by their total latency, ignoring idle (this may be very large) per host.

##### Structures

```SQL
mariadb> desc waits_by_host_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| host          | varchar(60)         | YES  |     | NULL    |       |
| event         | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | text                | YES  |     | NULL    |       |
| avg_latency   | text                | YES  |     | NULL    |       |
| max_latency   | text                | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
6 rows in set (0.36 sec)

mariadb> desc x$waits_by_host_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| host          | varchar(60)         | YES  |     | NULL    |       |
| event         | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| avg_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
| max_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
6 rows in set (0.25 sec)
```

##### Example

```SQL
 mariadb> select * from waits_by_host_by_latency;
  +------+-----------------------------------------------------+--------+---------------+-------------+-------------+
  | host | event                                               | total  | total_latency | avg_latency | max_latency |
  +------+-----------------------------------------------------+--------+---------------+-------------+-------------+
  | hal1 | wait/io/file/sql/file_parser                        |  13743 | 00:01:00.46   | 4.40 ms     | 231.88 ms   |
  | hal1 | wait/io/file/innodb/innodb_data_file                |   4699 | 3.02 s        | 643.38 us   | 46.93 ms    |
  | hal1 | wait/io/file/sql/FRM                                |  11462 | 2.60 s        | 226.83 us   | 61.72 ms    |
  | hal1 | wait/io/file/myisam/dfile                           |  26776 | 746.70 ms     | 27.89 us    | 308.79 ms   |
  | hal1 | wait/io/file/myisam/kfile                           |   7126 | 462.66 ms     | 64.93 us    | 88.76 ms    |
  | hal1 | wait/io/file/sql/dbopt                              |    179 | 137.58 ms     | 768.59 us   | 15.46 ms    |
  | hal1 | wait/io/file/csv/metadata                           |      8 | 86.60 ms      | 10.82 ms    | 50.32 ms    |
  | hal1 | wait/synch/mutex/mysys/IO_CACHE::append_buffer_lock | 798080 | 66.46 ms      | 82.94 ns    | 161.03 us   |
  | hal1 | wait/io/file/sql/binlog                             |     19 | 49.11 ms      | 2.58 ms     | 9.40 ms     |
  | hal1 | wait/io/file/sql/misc                               |     26 | 22.38 ms      | 860.80 us   | 15.30 ms    |
  | hal1 | wait/io/file/csv/data                               |      4 | 297.46 us     | 74.37 us    | 111.93 us   |
  | hal1 | wait/synch/rwlock/sql/MDL_lock::rwlock              |    944 | 287.86 us     | 304.62 ns   | 874.64 ns   |
  | hal1 | wait/io/file/archive/data                           |      4 | 82.71 us      | 20.68 us    | 40.74 us    |
  | hal1 | wait/synch/mutex/myisam/MYISAM_SHARE::intern_lock   |     60 | 12.21 us      | 203.20 ns   | 512.72 ns   |
  | hal1 | wait/synch/mutex/innodb/trx_mutex                   |     81 | 5.93 us       | 73.14 ns    | 252.59 ns   |
  +------+-----------------------------------------------------+--------+---------------+-------------+-------------+
```

#### waits_global_by_latency / x$waits_global_by_latency

##### Description

Lists the top wait events by their total latency, ignoring idle (this may be very large).

##### Structures

```SQL
mariadb> desc waits_global_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| events        | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | text                | YES  |     | NULL    |       |
| avg_latency   | text                | YES  |     | NULL    |       |
| max_latency   | text                | YES  |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
5 rows in set (0.01 sec)

mariadb> desc x$waits_global_by_latency;
+---------------+---------------------+------+-----+---------+-------+
| Field         | Type                | Null | Key | Default | Extra |
+---------------+---------------------+------+-----+---------+-------+
| events        | varchar(128)        | NO   |     | NULL    |       |
| total         | bigint(20) unsigned | NO   |     | NULL    |       |
| total_latency | bigint(20) unsigned | NO   |     | NULL    |       |
| avg_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
| max_latency   | bigint(20) unsigned | NO   |     | NULL    |       |
+---------------+---------------------+------+-----+---------+-------+
5 rows in set (0.03 sec)
```

##### Example

```SQL
mariadb> select * from waits_global_by_latency;
+-----------------------------------------------------+---------+---------------+-------------+-------------+
| events                                              | total   | total_latency | avg_latency | max_latency |
+-----------------------------------------------------+---------+---------------+-------------+-------------+
| wait/io/file/sql/file_parser                        | 14936   | 00:01:06.64   | 4.46 ms     | 231.88 ms   |
| wait/io/file/innodb/innodb_data_file                |    6133 | 6.31 s        | 1.03 ms     | 147.56 ms   |
| wait/io/file/sql/FRM                                |   12677 | 2.83 s        | 223.37 us   | 40.86 ms    |
| wait/io/file/myisam/dfile                           |   28446 | 754.40 ms     | 26.52 us    | 308.79 ms   |
| wait/io/file/myisam/kfile                           |    7572 | 491.17 ms     | 64.87 us    | 88.76 ms    |
| wait/io/file/sql/relaylog                           |       9 | 252.28 ms     | 28.03 ms    | 144.17 ms   |
| wait/io/file/sql/binlog                             |      76 | 242.87 ms     | 3.20 ms     | 153.72 ms   |
| wait/io/file/sql/binlog_index                       |      21 | 173.07 ms     | 8.24 ms     | 81.83 ms    |
| wait/io/file/sql/dbopt                              |     184 | 149.52 ms     | 812.62 us   | 15.46 ms    |
| wait/io/file/innodb/innodb_log_file                 |      20 | 117.17 ms     | 5.86 ms     | 36.53 ms    |
| wait/synch/mutex/mysys/IO_CACHE::append_buffer_lock | 1197128 | 99.27 ms      | 82.56 ns    | 161.03 us   |
| wait/io/file/csv/metadata                           |       8 | 86.60 ms      | 10.82 ms    | 50.32 ms    |
| wait/io/file/sql/relaylog_index                     |      10 | 60.10 ms      | 6.01 ms     | 48.04 ms    |
| wait/io/file/sql/ERRMSG                             |       5 | 35.41 ms      | 7.08 ms     | 31.78 ms    |
| wait/io/file/sql/misc                               |      28 | 22.40 ms      | 800.06 us   | 15.30 ms    |
| wait/io/file/mysys/charset                          |       3 | 7.46 ms       | 2.49 ms     | 4.13 ms     |
| wait/io/file/sql/casetest                           |       5 | 6.01 ms       | 1.20 ms     | 5.86 ms     |
| wait/io/file/sql/pid                                |       3 | 5.96 ms       | 1.99 ms     | 3.06 ms     |
| wait/synch/rwlock/sql/MDL_lock::rwlock              |    1396 | 420.58 us     | 301.22 ns   | 874.64 ns   |
| wait/io/file/csv/data                               |       4 | 297.46 us     | 74.37 us    | 111.93 us   |
| wait/io/file/mysys/cnf                              |       5 | 154.97 us     | 30.99 us    | 58.87 us    |
| wait/io/file/archive/data                           |       4 | 82.71 us      | 20.68 us    | 40.74 us    |
| wait/synch/mutex/myisam/MYISAM_SHARE::intern_lock   |      90 | 19.23 us      | 213.38 ns   | 576.81 ns   |
| wait/io/file/sql/global_ddl_log                     |       2 | 18.64 us      | 9.32 us     | 16.40 us    |
| wait/synch/mutex/innodb/trx_mutex                   |     108 | 8.23 us       | 76.15 ns    | 365.69 ns   |
+-----------------------------------------------------+---------+---------------+-------------+-------------+
```

### Functions

#### extract_schema_from_file_name

##### Description

Takes a raw file path, and attempts to extract the schema name from it.

Useful for when interacting with Performance Schema data concerning IO statistics, for example.

Currently relies on the fact that a table data file will be within a specified database directory (will not work with partitions or tables that specify an individual DATA_DIRECTORY).

##### Parameters

* path (VARCHAR(512)): The full file path to a data file to extract the schema name from.

##### Returns

VARCHAR(64)

##### Example
```SQL
mariadb> SELECT sys.extract_schema_from_file_name('/var/lib/mysql/employees/employee.ibd');
+----------------------------------------------------------------------------+
| sys.extract_schema_from_file_name('/var/lib/mysql/employees/employee.ibd') |
+----------------------------------------------------------------------------+
| employees                                                                  |
+----------------------------------------------------------------------------+
1 row in set (0.00 sec)
```

#### extract_table_from_file_name

##### Description

Takes a raw file path, and extracts the table name from it.

Useful for when interacting with Performance Schema data concerning IO statistics, for example.

##### Parameters

* path (VARCHAR(512)): The full file path to a data file to extract the table name from.

##### Returns

VARCHAR(64)

##### Example
```SQL
mariadb> SELECT sys.extract_table_from_file_name('/var/lib/mysql/employees/employee.ibd');
+---------------------------------------------------------------------------+
| sys.extract_table_from_file_name('/var/lib/mysql/employees/employee.ibd') |
+---------------------------------------------------------------------------+
| employee                                                                  |
+---------------------------------------------------------------------------+
1 row in set (0.02 sec)
```         

#### format_bytes

##### Description

Takes a raw bytes value, and converts it to a human readable format.

##### Parameters

* bytes (TEXT): A raw bytes value.

##### Returns

TEXT

##### Example
```SQL
mariadb> SELECT format_bytes(2348723492723746) AS size;
+----------+
| size     |
+----------+
| 2.09 PiB |
+----------+
1 row in set (0.00 sec)

mariadb> SELECT format_bytes(2348723492723) AS size;
+----------+
| size     |
+----------+
| 2.14 TiB |
+----------+
1 row in set (0.00 sec)

mariadb> SELECT format_bytes(23487234) AS size;
+-----------+
| size      |
+-----------+
| 22.40 MiB |
+-----------+
1 row in set (0.00 sec)
```

#### format_path

##### Description

Takes a raw path value, and strips out the datadir or tmpdir replacing with @@datadir and @@tmpdir respectively. 

Also normalizes the paths across operating systems, so backslashes on Windows are converted to forward slashes.

##### Parameters

* path (VARCHAR(512)): The raw file path value to format.

##### Returns

VARCHAR(512) CHARSET UTF8

##### Example
```SQL
mariadb> select @@datadir;
+-----------------------------------------------+
| @@datadir                                     |
+-----------------------------------------------+
| /Users/mark/sandboxes/SmallTree/AMaster/data/ |
+-----------------------------------------------+
1 row in set (0.06 sec)

mariadb> select format_path('/Users/mark/sandboxes/SmallTree/AMaster/data/mysql/proc.MYD') AS path;
+--------------------------+
| path                     |
+--------------------------+
| @@datadir/mysql/proc.MYD |
+--------------------------+
1 row in set (0.03 sec)
```

#### format_statement

##### Description

Formats a normalized statement, truncating it if it is > 64 characters long by default.

To configure the length to truncate the statement to by default, update the `statement_truncate_len` variable with `sys_config` table to a different value. Alternatively, to change it just for just your particular session, use `SET @sys.statement_truncate_len := <some new value>`.

Useful for printing statement related data from Performance Schema from the command line.

##### Parameters

* statement (LONGTEXT): The statement to format.

##### Returns

LONGTEXT

##### Example
```SQL
mariadb> SELECT sys.format_statement(digest_text)
    ->   FROM performance_schema.events_statements_summary_by_digest
    ->  ORDER by sum_timer_wait DESC limit 5;
+-------------------------------------------------------------------+
| sys.format_statement(digest_text)                                 |
+-------------------------------------------------------------------+
| CREATE SQL SECURITY INVOKER VI ... KE ? AND `variable_value` > ?  |
| CREATE SQL SECURITY INVOKER VI ... ait` IS NOT NULL , `esc` . ... |
| CREATE SQL SECURITY INVOKER VI ... ait` IS NOT NULL , `sys` . ... |
| CREATE SQL SECURITY INVOKER VI ...  , `compressed_size` ) ) DESC  |
| CREATE SQL SECURITY INVOKER VI ... LIKE ? ORDER BY `timer_start`  |
+-------------------------------------------------------------------+
5 rows in set (0.00 sec)
```

#### format_time

##### Description

Takes a raw picoseconds value, and converts it to a human readable form.
             
Picoseconds are the precision that all latency values are printed in within Performance Schema, however are not user friendly when wanting to scan output from the command line.

##### Parameters

* picoseconds (TEXT): The raw picoseconds value to convert.

##### Returns

TEXT

##### Example
```SQL
mariadb> select format_time(342342342342345);
+------------------------------+
| format_time(342342342342345) |
+------------------------------+
| 00:05:42                     |
+------------------------------+
1 row in set (0.00 sec)

mariadb> select format_time(342342342);
+------------------------+
| format_time(342342342) |
+------------------------+
| 342.34 us              |
+------------------------+
1 row in set (0.00 sec)

mariadb> select format_time(34234);
 +--------------------+
| format_time(34234) |
+--------------------+
| 34.23 ns           |
+--------------------+
1 row in set (0.00 sec)
```

#### list_add

##### Description

Takes a list, and a value to add to the list, and returns the resulting list.

Useful for altering certain session variables, like sql_mode or optimizer_switch for instance.

##### Parameters

in_list (TEXT): The comma separated list to add a value to

in_add_value (TEXT): The value to add to the input list

##### Returns

TEXT

##### Example

```SQL
mariadb> select @@sql_mode;
+-----------------------------------------------------------------------------------+
| @@sql_mode                                                                        |
+-----------------------------------------------------------------------------------+
| ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
+-----------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mariadb> set sql_mode = sys.list_add(@@sql_mode, 'ANSI_QUOTES');
Query OK, 0 rows affected (0.06 sec)

mariadb> select @@sql_mode;
+-----------------------------------------------------------------------------------------------+
| @@sql_mode                                                                                    |
+-----------------------------------------------------------------------------------------------+
| ANSI_QUOTES,ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
+-----------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)
```

#### list_drop

##### Description

Takes a list, and a value to attempt to remove from the list, and returns the resulting list.

Useful for altering certain session variables, like sql_mode or optimizer_switch for instance.

##### Parameters

in_list (TEXT): The comma separated list to drop a value from

in_drop_value (TEXT): The value to drop from the input list

##### Returns

TEXT

##### Example

```SQL
mariadb> select @@sql_mode;
+-----------------------------------------------------------------------------------------------+
| @@sql_mode                                                                                    |
+-----------------------------------------------------------------------------------------------+
| ANSI_QUOTES,ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
+-----------------------------------------------------------------------------------------------+
1 row in set (0.00 sec)

mariadb> set sql_mode = sys.list_drop(@@sql_mode, 'ONLY_FULL_GROUP_BY');
Query OK, 0 rows affected (0.03 sec)

mariadb> select @@sql_mode;
+----------------------------------------------------------------------------+
| @@sql_mode                                                                 |
+----------------------------------------------------------------------------+
| ANSI_QUOTES,STRICT_TRANS_TABLES,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION |
+----------------------------------------------------------------------------+
1 row in set (0.00 sec)
```

#### ps_is_account_enabled

##### Description

Determines whether instrumentation of an account is enabled within Performance Schema.

##### Parameters

* in_host VARCHAR(60): The hostname of the account to check.
* in_user VARCHAR(32): The username of the account to check.

##### Returns

ENUM('YES', 'NO')

##### Example
```SQL
mariadb> SELECT sys.ps_is_account_enabled('localhost', 'root');
+------------------------------------------------+
| sys.ps_is_account_enabled('localhost', 'root') |
+------------------------------------------------+
| YES                                            |
+------------------------------------------------+
1 row in set (0.01 sec)
```

#### ps_is_consumer_enabled

##### Description

Determines whether a consumer is enabled (taking the consumer hierarchy into consideration) within the Performance Schema.

##### Parameters

* in_consumer VARCHAR(64): The name of the consumer to check.

##### Returns

ENUM('YES', 'NO')

##### Example
```SQL
mariadb> SELECT sys.ps_is_consumer_enabled('events_stages_history');
+-----------------------------------------------------+
| sys.ps_is_consumer_enabled('events_stages_history') |
+-----------------------------------------------------+
| NO                                                  |
+-----------------------------------------------------+
1 row in set (0.00 sec)
```

#### ps_is_instrument_default_enabled

##### Description

Returns whether an instrument is enabled by default in this version of MariaDB.

##### Parameters

* in_instrument VARCHAR(128): The instrument to check.

##### Returns

ENUM('YES', 'NO')

##### Example
```SQL
mariadb> SELECT sys.ps_is_instrument_default_enabled('statement/sql/select');
+--------------------------------------------------------------+
| sys.ps_is_instrument_default_enabled('statement/sql/select') |
+--------------------------------------------------------------+
| YES                                                          |
+--------------------------------------------------------------+
1 row in set (0.00 sec)
```

#### ps_is_instrument_default_timed

##### Description

Returns whether an instrument is timed by default in this version of MariaDB.

##### Parameters

* in_instrument VARCHAR(128): The instrument to check.

##### Returns

ENUM('YES', 'NO')

##### Example
```SQL
mariadb> SELECT sys.ps_is_instrument_default_timed('statement/sql/select');
+------------------------------------------------------------+
| sys.ps_is_instrument_default_timed('statement/sql/select') |
+------------------------------------------------------------+
| YES                                                        |
+------------------------------------------------------------+
1 row in set (0.00 sec)
```

#### ps_is_thread_instrumented

##### Description

Checks whether the provided connection id is instrumented within Performance Schema.

##### Parameters

* in_connection_id (BIGINT UNSIGNED): the id of the connection to check.

##### Returns

ENUM('YES', 'NO', 'UNKNOWN')

##### Example
```SQL
mariadb> SELECT sys.ps_is_thread_instrumented(CONNECTION_ID());
+------------------------------------------------+
| sys.ps_is_thread_instrumented(CONNECTION_ID()) |
+------------------------------------------------+
| YES                                            |
+------------------------------------------------+
1 row in set (0.10 sec)
```

#### ps_thread_id

##### Description

Return the Performance Schema THREAD_ID for the specified connection ID.

##### Parameters

* in_connection_id (BIGINT UNSIGNED): The id of the connection to return the thread id for. If NULL, the current connection thread id is returned.

##### Returns

BIGINT UNSIGNED

##### Example
```SQL
mariadb> SELECT sys.ps_thread_id(79);
+----------------------+
| sys.ps_thread_id(79) |
+----------------------+
|                   98 |
+----------------------+
1 row in set (0.00 sec)

mariadb> SELECT sys.ps_thread_id(CONNECTION_ID());
+-----------------------------------+
| sys.ps_thread_id(CONNECTION_ID()) |
+-----------------------------------+
|                                98 |
+-----------------------------------+
1 row in set (0.00 sec)
```

#### ps_thread_stack

##### Description

Outputs a JSON formatted stack of all statements, stages and events within Performance Schema for the specified thread.

##### Parameters

* thd_id (BIGINT): The id of the thread to trace. This should match the thread_id column from the performance_schema.threads table.

##### Example

(line separation added for output)

```SQL
 mariadb> SELECT sys.ps_thread_stack(37, FALSE) AS thread_stack\G
*************************** 1. row ***************************
thread_stack: {"rankdir": "LR","nodesep": "0.10","stack_created": "2024-09-04 21:21:44",
"mysql_version": "10.6.19-MariaDB","mysql_user": "msandbox@localhost","events": []}

...
```

#### ps_thread_trx_info

##### Description

Returns a JSON object with info on the given thread's current transaction, and the statements it has already executed, derived from the `performance_schema.events_transactions_current` and `performance_schema.events_statements_history` tables (so the consumers for these also have to be enabled within Performance Schema to get full data in the object).

When the output exceeds the default truncation length (65535), a JSON error object is returned, such as:

`{ "error": "Trx info truncated: Row 6 was cut by GROUP_CONCAT()" }`

Similar error objects are returned for other warnings/and exceptions raised when calling the function.

The max length of the output of this function can be controlled with the `ps_thread_trx_info.max_length` variable set via `sys_config`, or the `@sys.ps_thread_trx_info.max_length` user variable, as appropriate.

##### Parameters

* in_thread_id (BIGINT UNSIGNED): The id of the thread to return the transaction info for.

##### Example

```SQL
SELECT sys.ps_thread_trx_info(48)\G
*************************** 1. row ***************************
sys.ps_thread_trx_info(48): [
  {
    "time": "790.70 us",
    "state": "COMMITTED",
    "mode": "READ WRITE",
    "autocommitted": "NO",
    "gtid": "AUTOMATIC",
    "isolation": "REPEATABLE READ",
    "statements_executed": [
      {
        "sql_text": "INSERT INTO info VALUES (1, \'foo\')",
        "time": "471.02 us",
        "schema": "trx",
        "rows_examined": 0,
        "rows_affected": 1,
        "rows_sent": 0,
        "tmp_tables": 0,
        "tmp_disk_tables": 0,
        "sort_rows": 0,
        "sort_merge_passes": 0
      },
      {
        "sql_text": "COMMIT",
        "time": "254.42 us",
        "schema": "trx",
        "rows_examined": 0,
        "rows_affected": 0,
        "rows_sent": 0,
        "tmp_tables": 0,
        "tmp_disk_tables": 0,
        "sort_rows": 0,
        "sort_merge_passes": 0
      }
    ]
  },
  {
    "time": "426.20 us",
    "state": "COMMITTED",
    "mode": "READ WRITE",
    "autocommitted": "NO",
    "gtid": "AUTOMATIC",
    "isolation": "REPEATABLE READ",
    "statements_executed": [
      {
        "sql_text": "INSERT INTO info VALUES (2, \'bar\')",
        "time": "107.33 us",
        "schema": "trx",
        "rows_examined": 0,
        "rows_affected": 1,
        "rows_sent": 0,
        "tmp_tables": 0,
        "tmp_disk_tables": 0,
        "sort_rows": 0,
        "sort_merge_passes": 0
      },
      {
        "sql_text": "COMMIT",
        "time": "213.23 us",
        "schema": "trx",
        "rows_examined": 0,
        "rows_affected": 0,
        "rows_sent": 0,
        "tmp_tables": 0,
        "tmp_disk_tables": 0,
        "sort_rows": 0,
        "sort_merge_passes": 0
      }
    ]
  }
]
1 row in set (0.03 sec)
```

#### quote_identifier

##### Description

Takes an unquoted identifier (schema name, table name, etc.) and
returns the identifier quoted with backticks.

##### Parameters

* in_identifier (TEXT): The identifier to quote.

##### Returns

TEXT

##### Example
```SQL
mariadb> SELECT sys.quote_identifier('my_identifier') AS Identifier;
+-----------------+
| Identifier      |
+-----------------+
| `my_identifier` |
+-----------------+
1 row in set (0.00 sec)

mariadb> SELECT sys.quote_identifier('my`idenfier') AS Identifier;
+----------------+
| Identifier     |
+----------------+
| `my``idenfier` |
+----------------+
1 row in set (0.00 sec)
```

#### sys_get_config

##### Description

Returns the value for the requested variable using the following logic:

1. If the option exists in sys.sys_config return the value from there.
2. Else fall back on the provided default value.

Notes for using sys_get_config():

* If the default value argument to sys_get_config() is NULL and case 2. is reached, NULL is returned.
  It is then expected that the caller is able to handle NULL for the given configuration option.
* The convention is to name the user variables @sys.<name of variable>. It is <name of variable> that
  is stored in the sys_config table and is what is expected as the argument to sys_get_config().
* If you want to check whether the configuration option has already been set and if not assign with
  the return value of sys_get_config() you can use IFNULL(...) (see example below). However this should
  not be done inside a loop (e.g. for each row in a result set) as for repeated calls where assignment
  is only needed in the first iteration using IFNULL(...) is expected to be significantly slower than
  using an IF (...) THEN ... END IF; block (see example below).

##### Parameters

* in_variable_name (VARCHAR(128)): The name of the config option to return the value for.
* in_default_value (VARCHAR(128)): The default value to return if the variable does not exist in sys.sys_config.

##### Returns

VARCHAR(128)

##### Example
```SQL
-- Get the configuration value from sys.sys_config falling back on 128 if the option is not present in the table.
mariadb> SELECT sys.sys_get_config('statement_truncate_len', 128) AS Value;
+-------+
| Value |
+-------+
| 64    |
+-------+
1 row in set (0.00 sec)

-- Check whether the option is already set, if not assign - IFNULL(...) one liner example.
mariadb> SET @sys.statement_truncate_len = IFNULL(@sys.statement_truncate_len, sys.sys_get_config('statement_truncate_len', 64));
Query OK, 0 rows affected (0.00 sec)

-- Check whether the option is already set, if not assign - IF ... THEN ... END IF example.
IF (@sys.statement_truncate_len IS NULL) THEN
    SET @sys.statement_truncate_len = sys.sys_get_config('statement_truncate_len', 64);
END IF;
```

#### version_major

##### Description

Returns the major version of MariaDB Server.

##### Returns

TINYINT UNSIGNED

##### Example
```SQL
mariadb> SELECT VERSION(), sys.version_major();
+-----------------+---------------------+
| VERSION()       | sys.version_major() |
+-----------------+---------------------+
| 10.6.19-MariaDB |                  10 |
+-----------------+---------------------+
1 row in set (0.00 sec)
```

#### version_minor

##### Description

Returns the minor (release series) version of MariaDB Server.

##### Returns

TINYINT UNSIGNED

##### Example
```SQL
mariadb> SELECT VERSION(), sys.server_minor();
+-----------------+---------------------+
| VERSION()       | sys.version_minor() |
+-----------------+---------------------+
| 10.6.19-MariaDB |                   6 |
+-----------------+---------------------+
1 row in set (0.00 sec)
```

#### version_patch

##### Description

Returns the patch release version of MariaDB Server.

##### Returns

TINYINT UNSIGNED

##### Example
```SQL
mariadb> SELECT VERSION(), sys.version_patch();
+-----------------+---------------------+
| VERSION()       | sys.version_patch() |
+-----------------+---------------------+
| 10.6.19-MariaDB |                  19 |
+-----------------+---------------------+
1 row in set (0.00 sec)
```


### Procedures

#### create_synonym_db

##### Description

Takes a source database name and synonym name, and then creates the synonym database with views that point to all of the tables within the source database.

Useful for creating a "ps" synonym for "performance_schema", or "is" instead of "information_schema", for example.

##### Parameters

* in_db_name (VARCHAR(64)):
** The database name that you would like to create a synonym for.
* in_synonym (VARCHAR(64)):
** The database synonym name.

##### Example
```SQL
mariadb> SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
| test               |
+--------------------+
5 rows in set (0.00 sec)

mariadb> CALL sys.create_synonym_db('performance_schema', 'ps');
+---------------------------------------+
| summary                               |
+---------------------------------------+
| Created 74 views in the `ps` database |
+---------------------------------------+
1 row in set (8.57 sec)

Query OK, 0 rows affected (8.57 sec)

mariadb> SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| ps                 |
| sys                |
| test               |
+--------------------+
6 rows in set (0.00 sec)

mariadb> SHOW FULL TABLES FROM ps;
+-----------------------------------------+------------+
| Tables_in_ps                            | Table_type |
+-----------------------------------------+------------+
| accounts                                | VIEW       |
| cond_instances                          | VIEW       |
| events_stages_current                   | VIEW       |
| events_stages_history                   | VIEW       |
...
```

#### diagnostics

##### Description

Create a report of the current status of the server for diagnostics purposes. Data collected includes (some items depends on versions and settings):

* The GLOBAL VARIABLES
* Several sys schema views including metrics or equivalent (depending on version and settings)
* Queries in the 95th percentile
* Replication (both master and slave) information.

Some of the sys schema views are calculated as initial (optional), overall, delta:

* The initial view is the content of the view at the start of this procedure.
  This output will be the same as the the start values used for the delta view.
  The initial view is included if @sys.diagnostics.include_raw = 'ON'.
* The overall view is the content of the view at the end of this procedure.
  This output is the same as the end values used for the delta view.
  The overall view is always included.
* The delta view is the difference from the beginning to the end. Note that for min and max values
  they are simply the min or max value from the end view respectively, so does not necessarily reflect
  the minimum/maximum value in the monitored period.
  Note: except for the metrics view the delta is only calculation between the first and last outputs.

Requires the SUPER privilege for "SET sql_log_bin = 0;".

Some configuration options are supported:

* sys.diagnostics.allow_i_s_tables
  Specifies whether it is allowed to do table scan queries on information_schema.TABLES. This can be expensive if there
  are many tables. Set to 'ON' to allow, 'OFF' to not allow.
  Default is 'OFF'.

* sys.diagnostics.include_raw
  Set to 'ON' to include the raw data (e.g. the original output of "SELECT * FROM sys.metrics").
  Use this to get the initial values of the various views.
  Default is 'OFF'.

* sys.statement_truncate_len
  How much of queries in the process list output to include.
  Default is 64.

* sys.debug
  Whether to provide debugging output.
  Default is 'OFF'. Set to 'ON' to include.

##### Parameters

* in_max_runtime (INT UNSIGNED):
The maximum time to keep collecting data.
Use NULL to get the default which is 60 seconds, otherwise enter a value greater than 0.
* in_interval (INT UNSIGNED):
How long to sleep between data collections.
Use NULL to get the default which is 30 seconds, otherwise enter a value greater than 0.
* in_auto_config (ENUM('current', 'medium', 'full'))
Automatically enable Performance Schema instruments and consumers.
NOTE: The more that are enabled, the more impact on the performance.
If another setting the 'current' is chosen, the current settings
are restored at the end of the procedure.
Supported values are:
** current - use the current settings.
** medium - enable some settings.
** full - enables all settings. This will have a big impact on the
   performance - be careful using this option.

##### Example
```SQL
mariadb> TEE diag.out;
mariadb> CALL sys.diagnostics(120, 30, 'current');
...
mariadb> NOTEE;
```

#### ps_setup_disable_background_threads

##### Description

Disable all background thread instrumentation within Performance Schema.

##### Parameters

None.

##### Example
```SQL
mariadb> CALL sys.ps_setup_disable_background_threads();
+--------------------------------+
| summary                        |
+--------------------------------+
| Disabled 18 background threads |
+--------------------------------+
1 row in set (0.00 sec)
```

#### execute_prepared_stmt

##### Description

Takes the query in the argument and executes it using a prepared statement. The prepared statement is deallocated,
so the procedure is mainly useful for executing one off dynamically created queries.

The sys_execute_prepared_stmt prepared statement name is used for the query and is required not to exist.

##### Parameters

* in_query (longtext CHARACTER SET UTF8):
** The query to execute.

The following configuration option is supported:

   * sys.debug
     Whether to provide debugging output.
     Default is 'OFF'. Set to 'ON' to include.

##### Example
```SQL
mariadb> CALL sys.execute_prepared_stmt('SELECT * FROM sys.sys_config');
+------------------------+-------+---------------------+--------+
| variable               | value | set_time            | set_by |
+------------------------+-------+---------------------+--------+
| statement_truncate_len | 64    | 2015-06-30 13:06:00 | NULL   |
+------------------------+-------+---------------------+--------+
1 row in set (0.00 sec)

Query OK, 0 rows affected (0.00 sec)
```

#### ps_setup_disable_consumer

##### Description

Disables consumers within Performance Schema matching the input pattern.

##### Parameters

* consumer (VARCHAR(128)): A LIKE pattern match (using "%consumer%") of consumers to disable

##### Example

To disable all consumers:
```SQL
mariadb> CALL sys.ps_setup_disable_consumer('');
+--------------------------+
| summary                  |
+--------------------------+
| Disabled 15 consumers    |
+--------------------------+
1 row in set (0.02 sec)
```

To disable just the event_stage consumers:
```SQL
mariadb> CALL sys.ps_setup_disable_consumer('stage');
+------------------------+
| summary                |
+------------------------+
| Disabled 3 consumers   |
+------------------------+
1 row in set (0.00 sec)
```

#### ps_setup_disable_instrument

##### Description

Disables instruments within Performance Schema  matching the input pattern.

##### Parameters

* in_pattern (VARCHAR(128)): A LIKE pattern match (using "%in_pattern%") of events to disable

##### Example

To disable all mutex instruments:
```SQL
mariadb> CALL sys.ps_setup_disable_instrument('wait/synch/mutex');
+--------------------------+
| summary                  |
+--------------------------+
| Disabled 155 instruments |
+--------------------------+
1 row in set (0.02 sec)
```
To disable just a specific TCP/IP based network IO instrument:
```SQL
mariadb> CALL sys.ps_setup_disable_instrument('wait/io/socket/sql/server_tcpip_socket');
+------------------------+
| summary                |
+------------------------+
| Disabled 1 instruments |
+------------------------+
1 row in set (0.00 sec)
```
To disable all instruments:
```SQL
mariadb> CALL sys.ps_setup_disable_instrument('');
+--------------------------+
| summary                  |
+--------------------------+
| Disabled 547 instruments |
+--------------------------+
1 row in set (0.01 sec)
```

#### ps_setup_disable_thread

##### Description

Disable the given connection/thread in Performance Schema.

##### Parameters

* in_connection_id (BIGINT): The connection ID (PROCESSLIST_ID from performance_schema.threads or the ID shown within SHOW PROCESSLIST)

##### Example
```SQL
mariadb> CALL sys.ps_setup_disable_thread(3);
+-------------------+
| summary           |
+-------------------+
| Disabled 1 thread |
+-------------------+
1 row in set (0.01 sec)
```
To disable the current connection:
```SQL
mariadb> CALL sys.ps_setup_disable_thread(CONNECTION_ID());
+-------------------+
| summary           |
+-------------------+
| Disabled 1 thread |
+-------------------+
1 row in set (0.00 sec)
```

#### ps_setup_enable_background_threads

##### Description

Enable all background thread instrumentation within Performance Schema.

##### Parameters

None.

##### Example
```SQL
mariadb> CALL sys.ps_setup_enable_background_threads();
+-------------------------------+
| summary                       |
+-------------------------------+
| Enabled 18 background threads |
+-------------------------------+
1 row in set (0.00 sec)
```

#### ps_setup_enable_consumer

##### Description

Enables consumers within Performance Schema matching the input pattern.

##### Parameters

* consumer (VARCHAR(128)): A LIKE pattern match (using "%consumer%") of consumers to enable

##### Example

To enable all consumers:
```SQL
mariadb> CALL sys.ps_setup_enable_consumer('');
+-------------------------+
| summary                 |
+-------------------------+
| Enabled 10 consumers    |
+-------------------------+
1 row in set (0.02 sec)
```

To enable just "waits" consumers:
```SQL
mariadb> CALL sys.ps_setup_enable_consumer('waits');
+-----------------------+
| summary               |
+-----------------------+
| Enabled 3 consumers   |
+-----------------------+
1 row in set (0.00 sec)
```

#### ps_setup_enable_instrument

##### Description

Enables instruments within Performance Schema matching the input pattern.

##### Parameters


* in_pattern (VARCHAR(128)): A LIKE pattern match (using "%in_pattern%") of events to enable

##### Example

To enable all mutex instruments:
```SQL
mariadb> CALL sys.ps_setup_enable_instrument('wait/synch/mutex');
+-------------------------+
| summary                 |
+-------------------------+
| Enabled 155 instruments |
+-------------------------+
1 row in set (0.02 sec)
```
To enable just a specific TCP/IP based network IO instrument:
```SQL
mariadb> CALL sys.ps_setup_enable_instrument('wait/io/socket/sql/server_tcpip_socket');
+-----------------------+
| summary               |
+-----------------------+
| Enabled 1 instruments |
+-----------------------+
1 row in set (0.00 sec)
```
To enable all instruments:
```SQL
mariadb> CALL sys.ps_setup_enable_instrument('');
+-------------------------+
| summary                 |
+-------------------------+
| Enabled 547 instruments |
+-------------------------+
1 row in set (0.01 sec)
```

#### ps_setup_enable_thread

##### Description

Enable the given connection/thread in Performance Schema.

##### Parameters


* in_connection_id (BIGINT): The connection ID (PROCESSLIST_ID from performance_schema.threads or the ID shown within SHOW PROCESSLIST)

##### Example
```SQL
mariadb> CALL sys.ps_setup_enable_thread(3);
+------------------+
| summary          |
+------------------+
| Enabled 1 thread |
+------------------+
1 row in set (0.01 sec)
```
To enable the current connection:
```SQL
mariadb> CALL sys.ps_setup_enable_thread(CONNECTION_ID());
+------------------+
| summary          |
+------------------+
| Enabled 1 thread |
+------------------+
1 row in set (0.00 sec)
```

#### ps_setup_reload_saved

##### Description

Reloads a saved Performance Schema configuration, so that you can alter the setup for debugging purposes, but restore it to a previous state.
             
Use the companion procedure - ps_setup_save(), to save a configuration.

Requires the SUPER privilege for "SET sql_log_bin = 0;".

##### Parameters

None.

##### Example
```SQL
mariadb> CALL sys.ps_setup_save();
Query OK, 0 rows affected (0.08 sec)

mariadb> UPDATE performance_schema.setup_instruments SET enabled = 'YES', timed = 'YES';
Query OK, 547 rows affected (0.40 sec)
Rows matched: 784  Changed: 547  Warnings: 0

/* Run some tests that need more detailed instrumentation here */

mariadb> CALL sys.ps_setup_reload_saved();
Query OK, 0 rows affected (0.32 sec)
```

#### ps_setup_reset_to_default

##### Description

Resets the Performance Schema setup to the default settings.

##### Parameters

* in_verbose (BOOLEAN): Whether to print each setup stage (including the SQL) whilst running.

##### Example
```SQL
mariadb> CALL sys.ps_setup_reset_to_default(true)\G
*************************** 1. row ***************************
status: Resetting: setup_actors
DELETE
FROM performance_schema.setup_actors
WHERE NOT (HOST = '%' AND USER = '%' AND ROLE = '%')
1 row in set (0.00 sec)

*************************** 1. row ***************************
status: Resetting: setup_actors
INSERT IGNORE INTO performance_schema.setup_actors
VALUES ('%', '%', '%')
1 row in set (0.00 sec)
...

mariadb> CALL sys.ps_setup_reset_to_default(false)\G
Query OK, 0 rows affected (0.00 sec)
```

#### ps_setup_save

##### Description

Saves the current configuration of Performance Schema, so that you can alter the setup for debugging purposes, but restore it to a previous state.

Use the companion procedure - ps_setup_reload_saved(), to restore the saved config.

The named lock "sys.ps_setup_save" is taken before the current configuration is saved. If the attempt to get the named lock times out, an error occurs.

The lock is released after the settings have been restored by calling ps_setup_reload_saved().

Requires the SUPER privilege for "SET sql_log_bin = 0;".

##### Parameters

* in_timeout (INT): The timeout in seconds used when trying to obtain the lock. A negative timeout means infinite timeout.

##### Example
```SQL
mariadb> CALL sys.ps_setup_save(-1);
Query OK, 0 rows affected (0.08 sec)

mariadb> UPDATE performance_schema.setup_instruments 
    ->    SET enabled = 'YES', timed = 'YES';
Query OK, 547 rows affected (0.40 sec)
Rows matched: 784  Changed: 547  Warnings: 0

/* Run some tests that need more detailed instrumentation here */

mariadb> CALL sys.ps_setup_reload_saved();
Query OK, 0 rows affected (0.32 sec)
```

#### ps_setup_show_disabled

##### Description

Shows all currently disabled Performance Schema configurations.


##### Parameters

* in_show_instruments (BOOLEAN): Whether to print disabled instruments (can print many items)
* in_show_threads (BOOLEAN): Whether to print disabled threads

##### Example
```SQL
mariadb> CALL sys.ps_setup_show_disabled(TRUE, TRUE);
+----------------------------+
| performance_schema_enabled |
+----------------------------+
|                          1 |
+----------------------------+
1 row in set (0.00 sec)

+--------------------+
| disabled_users     |
+--------------------+
| 'mark'@'localhost' |
+--------------------+
1 row in set (0.00 sec)

+-------------+----------------------+---------+-------+
| object_type | objects              | enabled | timed |
+-------------+----------------------+---------+-------+
| EVENT       | mysql.%              | NO      | NO    |
| EVENT       | performance_schema.% | NO      | NO    |
| EVENT       | information_schema.% | NO      | NO    |
| FUNCTION    | mysql.%              | NO      | NO    |
| FUNCTION    | performance_schema.% | NO      | NO    |
| FUNCTION    | information_schema.% | NO      | NO    |
| PROCEDURE   | mysql.%              | NO      | NO    |
| PROCEDURE   | performance_schema.% | NO      | NO    |
| PROCEDURE   | information_schema.% | NO      | NO    |
| TABLE       | mysql.%              | NO      | NO    |
| TABLE       | performance_schema.% | NO      | NO    |
| TABLE       | information_schema.% | NO      | NO    |
| TRIGGER     | mysql.%              | NO      | NO    |
| TRIGGER     | performance_schema.% | NO      | NO    |
| TRIGGER     | information_schema.% | NO      | NO    |
+-------------+----------------------+---------+-------+
15 rows in set (0.00 sec)

+----------------------------------+
| disabled_consumers               |
+----------------------------------+
| events_stages_current            |
| events_stages_history            |
| events_stages_history_long       |
| events_statements_history        |
| events_statements_history_long   |
| events_transactions_history      |
| events_transactions_history_long |
| events_waits_current             |
| events_waits_history             |
| events_waits_history_long        |
+----------------------------------+
10 rows in set (0.00 sec)

Empty set (0.00 sec)
             
+---------------------------------------------------------------------------------------+-------+
| disabled_instruments                                                                  | timed |
+---------------------------------------------------------------------------------------+-------+
| wait/synch/mutex/sql/TC_LOG_MMAP::LOCK_tc                                             | NO    |
| wait/synch/mutex/sql/LOCK_des_key_file                                                | NO    |
| wait/synch/mutex/sql/MYSQL_BIN_LOG::LOCK_commit                                       | NO    |
...
| memory/sql/servers_cache                                                              | NO    |
| memory/sql/udf_mem                                                                    | NO    |
| wait/lock/metadata/sql/mdl                                                            | NO    |
+---------------------------------------------------------------------------------------+-------+
547 rows in set (0.00 sec)

Query OK, 0 rows affected (0.01 sec)
```

#### ps_setup_show_disabled_consumers

##### Description

Shows all currently disabled consumers.

##### Parameters

None
 
##### Example

```SQL
mariadb> CALL sys.ps_setup_show_disabled_consumers();

+---------------------------+
| disabled_consumers        |
+---------------------------+
| events_statements_current |
| global_instrumentation    |
| thread_instrumentation    |
| statements_digest         |
+---------------------------+
4 rows in set (0.05 sec)
```

#### ps_setup_show_disabled_instruments

##### Description

Shows all currently disabled instruments.

##### Parameters

None
			 
##### Example

```SQL
mariadb> CALL sys.ps_setup_show_disabled_instruments();
```

#### ps_setup_show_enabled

##### Description

Shows all currently enabled Performance Schema configuration.

##### Parameters

* in_show_instruments (BOOLEAN): Whether to print enabled instruments (can print many items)
* in_show_threads (BOOLEAN): Whether to print enabled threads

##### Example
```SQL
mariadb> CALL sys.ps_setup_show_enabled(TRUE, TRUE);
+----------------------------+
| performance_schema_enabled |
+----------------------------+
|                          1 |
+----------------------------+
1 row in set (0.00 sec)

+---------------+
| enabled_users |
+---------------+
| '%'@'%'       |
+---------------+
1 row in set (0.01 sec)

+-------------+---------+---------+-------+
| object_type | objects | enabled | timed |
+-------------+---------+---------+-------+
| EVENT       | %.%     | YES     | YES   |
| FUNCTION    | %.%     | YES     | YES   |
| PROCEDURE   | %.%     | YES     | YES   |
| TABLE       | %.%     | YES     | YES   |
| TRIGGER     | %.%     | YES     | YES   |
+-------------+---------+---------+-------+
5 rows in set (0.01 sec)

+---------------------------+
| enabled_consumers         |
+---------------------------+
| events_statements_current |
| global_instrumentation    |
| thread_instrumentation    |
| statements_digest         |
+---------------------------+
4 rows in set (0.05 sec)

+---------------------------------+-------------+
| enabled_threads                 | thread_type |
+---------------------------------+-------------+
| sql/main                        | BACKGROUND  |
| sql/thread_timer_notifier       | BACKGROUND  |
| innodb/io_ibuf_thread           | BACKGROUND  |
| innodb/io_log_thread            | BACKGROUND  |
| innodb/io_read_thread           | BACKGROUND  |
| innodb/io_read_thread           | BACKGROUND  |
| innodb/io_write_thread          | BACKGROUND  |
| innodb/io_write_thread          | BACKGROUND  |
| innodb/page_cleaner             | BACKGROUND  |
| innodb/srv_lock_timeout_thread  | BACKGROUND  |
| innodb/srv_error_monitor_thread | BACKGROUND  |
| innodb/srv_monitor_thread       | BACKGROUND  |
| innodb/srv_master_thread        | BACKGROUND  |
| innodb/srv_purge_thread         | BACKGROUND  |
| innodb/srv_worker_thread        | BACKGROUND  |
| innodb/srv_worker_thread        | BACKGROUND  |
| innodb/srv_worker_thread        | BACKGROUND  |
| innodb/buf_dump_thread          | BACKGROUND  |
| innodb/dict_stats_thread        | BACKGROUND  |
| sql/signal_handler              | BACKGROUND  |
| sql/compress_gtid_table         | FOREGROUND  |
| root@localhost                  | FOREGROUND  |
+---------------------------------+-------------+
22 rows in set (0.01 sec)

+-------------------------------------+-------+
| enabled_instruments                 | timed |
+-------------------------------------+-------+
| wait/io/file/sql/map                | YES   |
| wait/io/file/sql/binlog             | YES   |
...
| statement/com/Error                 | YES   |
| statement/com/                      | YES   |
| idle                                | YES   |
+-------------------------------------+-------+
210 rows in set (0.08 sec)

Query OK, 0 rows affected (0.89 sec)
```

#### ps_setup_show_enabled_consumers

##### Description

Shows all currently enabled consumers.

##### Parameters

None

##### Example

```SQL
mariadb> CALL sys.ps_setup_show_enabled_consumers();

+---------------------------+
| enabled_consumers         |
+---------------------------+
| events_statements_current |
| global_instrumentation    |
| thread_instrumentation    |
| statements_digest         |
+---------------------------+
4 rows in set (0.05 sec)
```

#### ps_setup_show_enabled_instruments

##### Description

Shows all currently enabled instruments.

##### Parameters

None

##### Example

```SQL
mariadb> CALL sys.ps_setup_show_enabled_instruments();
```

#### ps_statement_avg_latency_histogram

##### Description

Outputs a textual histogram graph of the average latency values across all normalized queries tracked within the Performance Schema events_statements_summary_by_digest table.

Can be used to show a very high level picture of what kind of latency distribution statements running within this instance have.

##### Parameters

None.

##### Example
```SQL
mariadb> CALL sys.ps_statement_avg_latency_histogram()\G
*************************** 1. row ***************************
Performance Schema Statement Digest Average Latency Histogram:

  . = 1 unit
  * = 2 units
  # = 3 units

(0 - 38ms)     240 | ################################################################################
(38 - 77ms)    38  | ......................................
(77 - 115ms)   3   | ...
(115 - 154ms)  62  | *******************************
(154 - 192ms)  3   | ...
(192 - 231ms)  0   |
(231 - 269ms)  0   |
(269 - 307ms)  0   |
(307 - 346ms)  0   |
(346 - 384ms)  1   | .
(384 - 423ms)  1   | .
(423 - 461ms)  0   |
(461 - 499ms)  0   |
(499 - 538ms)  0   |
(538 - 576ms)  0   |
(576 - 615ms)  1   | .

  Total Statements: 350; Buckets: 16; Bucket Size: 38 ms;
```

#### ps_trace_statement_digest

##### Description

Traces all instrumentation within Performance Schema for a specific Statement Digest. 

When finding a statement of interest within the performance_schema.events_statements_summary_by_digest table, feed the DIGEST MD5 value in to this procedure, set how long to poll for, and at what interval to poll, and it will generate a report of all statistics tracked within Performance Schema for that digest for the interval.

It will also attempt to generate an EXPLAIN for the longest running example of the digest during the interval.

Note this may fail, as:

* Performance Schema truncates long SQL_TEXT values (and hence the EXPLAIN will fail due to parse errors)
* the default schema is sys (so tables that are not fully qualified in the query may not be found)
* some queries such as SHOW are not supported in EXPLAIN.

When the EXPLAIN fails, the error will be ignored and no EXPLAIN output generated.

Requires the SUPER privilege for "SET sql_log_bin = 0;".

##### Parameters

* in_digest VARCHAR(32): The statement digest identifier you would like to analyze
* in_runtime (INT): The number of seconds to run analysis for
* in_interval (DECIMAL(2,2)): The interval (in seconds, may be fractional) at which to try and take snapshots
* in_start_fresh (BOOLEAN): Whether to TRUNCATE the events_statements_history_long and events_stages_history_long tables before starting
* in_auto_enable (BOOLEAN): Whether to automatically turn on required consumers

##### Example
```SQL
mariadb> call ps_analyze_statement_digest('891ec6860f98ba46d89dd20b0c03652c', 10, 0.1, true, true);
+--------------------+
| SUMMARY STATISTICS |
+--------------------+
| SUMMARY STATISTICS |
+--------------------+
1 row in set (9.11 sec)

+------------+-----------+-----------+-----------+---------------+------------+------------+
| executions | exec_time | lock_time | rows_sent | rows_examined | tmp_tables | full_scans |
+------------+-----------+-----------+-----------+---------------+------------+------------+
|         21 | 4.11 ms   | 2.00 ms   |         0 |            21 |          0 |          0 |
+------------+-----------+-----------+-----------+---------------+------------+------------+
1 row in set (9.11 sec)

+------------------------------------------+-------+-----------+
| event_name                               | count | latency   |
+------------------------------------------+-------+-----------+
| stage/sql/checking query cache for query |    16 | 724.37 us |
| stage/sql/statistics                     |    16 | 546.92 us |
| stage/sql/freeing items                  |    18 | 520.11 us |
| stage/sql/init                           |    51 | 466.80 us |
...
| stage/sql/cleaning up                    |    18 | 11.92 us  |
| stage/sql/executing                      |    16 | 6.95 us   |
+------------------------------------------+-------+-----------+
17 rows in set (9.12 sec)

+---------------------------+
| LONGEST RUNNING STATEMENT |
+---------------------------+
| LONGEST RUNNING STATEMENT |
+---------------------------+
1 row in set (9.16 sec)
             
+-----------+-----------+-----------+-----------+---------------+------------+-----------+
| thread_id | exec_time | lock_time | rows_sent | rows_examined | tmp_tables | full_scan |
+-----------+-----------+-----------+-----------+---------------+------------+-----------+
|    166646 | 618.43 us | 1.00 ms   |         0 |             1 |          0 |         0 |
+-----------+-----------+-----------+-----------+---------------+------------+-----------+
1 row in set (9.16 sec)

// Truncated for clarity...
+-----------------------------------------------------------------+
| sql_text                                                        |
+-----------------------------------------------------------------+
| select hibeventhe0_.id as id1382_, hibeventhe0_.createdTime ... |
+-----------------------------------------------------------------+
1 row in set (9.17 sec)

+------------------------------------------+-----------+
| event_name                               | latency   |
+------------------------------------------+-----------+
| stage/sql/init                           | 8.61 us   |
| stage/sql/Waiting for query cache lock   | 453.23 us |
| stage/sql/init                           | 331.07 ns |
| stage/sql/checking query cache for query | 43.04 us  |
...
| stage/sql/freeing items                  | 30.46 us  |
| stage/sql/cleaning up                    | 662.13 ns |
+------------------------------------------+-----------+
             18 rows in set (9.23 sec)

+----+-------------+--------------+-------+---------------+-----------+---------+-------------+------+-------+
| id | select_type | table        | type  | possible_keys | key       | key_len | ref         | rows | Extra |
+----+-------------+--------------+-------+---------------+-----------+---------+-------------+------+-------+
|  1 | SIMPLE      | hibeventhe0_ | const | fixedTime     | fixedTime | 775     | const,const |    1 | NULL  |
+----+-------------+--------------+-------+---------------+-----------+---------+-------------+------+-------+
1 row in set (9.27 sec)

Query OK, 0 rows affected (9.28 sec)
```

#### ps_trace_thread

##### Description

Dumps all data within Performance Schema for an instrumented thread, to create a DOT formatted graph file. 

Each resultset returned from the procedure should be used for a complete graph

Requires the SUPER privilege for "SET sql_log_bin = 0;".

##### Parameters

* in_thread_id (INT): The thread that you would like a stack trace for
* in_outfile  (VARCHAR(255)): The filename the dot file will be written to
* in_max_runtime (DECIMAL(20,2)): The maximum time to keep collecting data. Use NULL to get the default which is 60 seconds.
* in_interval (DECIMAL(20,2)): How long to sleep between data collections. Use NULL to get the default which is 1 second.
* in_start_fresh (BOOLEAN): Whether to reset all Performance Schema data before tracing.
* in_auto_setup (BOOLEAN): Whether to disable all other threads and enable all consumers/instruments. This will also reset the settings at the end of the run.
* in_debug (BOOLEAN): Whether you would like to include file:lineno in the graph

##### Example
```SQL
mariadb> CALL sys.ps_trace_thread(25, CONCAT('/tmp/stack-', REPLACE(NOW(), ' ', '-'), '.dot'), NULL, NULL, TRUE, TRUE, TRUE);
+-------------------+
| summary           |
+-------------------+
| Disabled 1 thread |
+-------------------+
1 row in set (0.00 sec)

+---------------------------------------------+
| Info                                        |
+---------------------------------------------+
| Data collection starting for THREAD_ID = 25 |
+---------------------------------------------+
1 row in set (0.03 sec)

+-----------------------------------------------------------+
| Info                                                      |
+-----------------------------------------------------------+
| Stack trace written to /tmp/stack-2014-02-16-21:18:41.dot |
+-----------------------------------------------------------+
1 row in set (60.07 sec)

+-------------------------------------------------------------------+
| Convert to PDF                                                    |
+-------------------------------------------------------------------+
| dot -Tpdf -o /tmp/stack_25.pdf /tmp/stack-2014-02-16-21:18:41.dot |
+-------------------------------------------------------------------+
1 row in set (60.07 sec)

+-------------------------------------------------------------------+
| Convert to PNG                                                    |
+-------------------------------------------------------------------+
| dot -Tpng -o /tmp/stack_25.png /tmp/stack-2014-02-16-21:18:41.dot |
+-------------------------------------------------------------------+
1 row in set (60.07 sec)

+------------------+
| summary          |
+------------------+
| Enabled 1 thread |
+------------------+
1 row in set (60.32 sec)
```

#### ps_truncate_all_tables

##### Description

Truncates all summary tables within Performance Schema, resetting all aggregated instrumentation as a snapshot.

##### Parameters

* in_verbose (BOOLEAN): Whether to print each TRUNCATE statement before running

##### Example
```SQL
mariadb> CALL sys.ps_truncate_all_tables(false);
+---------------------+
| summary             |
+---------------------+
| Truncated 44 tables |
+---------------------+
1 row in set (0.10 sec)
```

#### statement_performance_analyzer

##### Description
Create a report of the statements running on the server.

The views are calculated based on the overall and/or delta activity.

Requires the SUPER privilege for "SET sql_log_bin = 0;".

The following configuration options are supported:

   * sys.statement_performance_analyzer.limit
     The maximum number of rows to include for the views that does not have a built-in limit (e.g. the 95th percentile view).
     If not set the limit is 100.

   * sys.statement_performance_analyzer.view
     Used together with the 'custom' view. If the value contains a space, it is considered a query, otherwise it must be
     an existing view querying the performance_schema.events_statements_summary_by_digest table. There cannot be any limit
     clause including in the query or view definition if @sys.statement_performance_analyzer.limit > 0.
     If specifying a view, use the same format as for in_table.

   * sys.debug
     Whether to provide debugging output.
     Default is 'OFF'. Set to 'ON' to include.

##### Parameters

* in_action (ENUM('snapshot', 'overall', 'delta', 'create_tmp', 'create_table', 'save', 'cleanup')):
  The action to take. Supported actions are:
    - snapshot      Store a snapshot. The default is to make a snapshot of the current content of
                    performance_schema.events_statements_summary_by_digest, but by setting in_table
                    this can be overwritten to copy the content of the specified table.
                    The snapshot is stored in the sys.tmp_digests temporary table.
    - overall       Generate analyzis based on the content specified by in_table. For the overall analyzis,
                    in_table can be NOW() to use a fresh snapshot. This will overwrite an existing snapshot.
                    Use NULL for in_table to use the existing snapshot. If in_table IS NULL and no snapshot
                    exists, a new will be created.
                    See also in_views and @sys.statement_performance_analyzer.limit.
    - delta         Generate a delta analysis. The delta will be calculated between the reference table in
                    in_table and the snapshot. An existing snapshot must exist.
                    The action uses the sys.tmp_digests_delta temporary table.
                    See also in_views and @sys.statement_performance_analyzer.limit.
    - create_table  Create a regular table suitable for storing the snapshot for later use, e.g. for
                    calculating deltas.
    - create_tmp    Create a temporary table suitable for storing the snapshot for later use, e.g. for
                    calculating deltas.
    - save          Save the snapshot in the table specified by in_table. The table must exists and have
                    the correct structure.
                    If no snapshot exists, a new is created.
    - cleanup       Remove the temporary tables used for the snapshot and delta.

* in_table (VARCHAR(129)):
  The table argument used for some actions. Use the format 'db1.t1' or 't1' without using any backticks (`)
  for quoting. Periods (.) are not supported in the database and table names.
  
  The meaning of the table for each action supporting the argument is:

    - snapshot      The snapshot is created based on the specified table. Set to NULL or NOW() to use
                    the current content of performance_schema.events_statements_summary_by_digest.
    - overall       The table with the content to create the overall analyzis for. The following values
                    can be used:
                      - A table name - use the content of that table.
                      - NOW()        - create a fresh snapshot and overwrite the existing snapshot.
                      - NULL         - use the last stored snapshot.
    - delta         The table name is mandatory and specified the reference view to compare the currently
                    stored snapshot against. If no snapshot exists, a new will be created.
    - create_table  The name of the regular table to create.
    - create_tmp    The name of the temporary table to create.
    - save          The name of the table to save the currently stored snapshot into.

* in_views (SET ('with_runtimes_in_95th_percentile', 'analysis', 'with_errors_or_warnings',
                 'with_full_table_scans', 'with_sorting', 'with_temp_tables', 'custom'))
  Which views to include:

    - with_runtimes_in_95th_percentile  Based on the sys.statements_with_runtimes_in_95th_percentile view
    - analysis                          Based on the sys.statement_analysis view
    - with_errors_or_warnings           Based on the sys.statements_with_errors_or_warnings view
    - with_full_table_scans             Based on the sys.statements_with_full_table_scans view
    - with_sorting                      Based on the sys.statements_with_sorting view
    - with_temp_tables                  Based on the sys.statements_with_temp_tables view
    - custom                            Use a custom view. This view must be specified in @sys.statement_performance_analyzer.view to an existing view or a query

  Default is to include all except 'custom'.

##### Example
```SQL
-- To create a report with the queries in the 95th percentile since last truncate of performance_schema.events_statements_summary_by_digest and the delta for a 1 minute period:
--
--    1. Create a temporary table to store the initial snapshot.
--    2. Create the initial snapshot.
--    3. Save the initial snapshot in the temporary table.
--    4. Wait one minute.
--    5. Create a new snapshot.
--    6. Perform analyzis based on the new snapshot.
--    7. Perform analyzis based on the delta between the initial and new snapshots.

mariadb> CALL sys.statement_performance_analyzer('create_tmp', 'mydb.tmp_digests_ini', NULL);
Query OK, 0 rows affected (0.08 sec)

mariadb> CALL sys.statement_performance_analyzer('snapshot', NULL, NULL);
Query OK, 0 rows affected (0.02 sec)

mariadb> CALL sys.statement_performance_analyzer('save', 'mydb.tmp_digests_ini', NULL);
Query OK, 0 rows affected (0.00 sec)

mariadb> DO SLEEP(60);
Query OK, 0 rows affected (1 min 0.00 sec)

mariadb> CALL sys.statement_performance_analyzer('snapshot', NULL, NULL);
Query OK, 0 rows affected (0.02 sec)

mariadb> CALL sys.statement_performance_analyzer('overall', NULL, 'with_runtimes_in_95th_percentile');
+-----------------------------------------+
| Next Output                             |
+-----------------------------------------+
| Queries with Runtime in 95th Percentile |
+-----------------------------------------+
1 row in set (0.05 sec)

...

mariadb> CALL sys.statement_performance_analyzer('delta', 'mydb.tmp_digests_ini', 'with_runtimes_in_95th_percentile');
+-----------------------------------------+
| Next Output                             |
+-----------------------------------------+
| Queries with Runtime in 95th Percentile |
+-----------------------------------------+
1 row in set (0.03 sec)

...


-- To create an overall report of the 95th percentile queries and the top 10 queries with full table scans:

mariadb> CALL sys.statement_performance_analyzer('snapshot', NULL, NULL);
Query OK, 0 rows affected (0.01 sec)                                   

mariadb> SET @sys.statement_performance_analyzer.limit = 10;
Query OK, 0 rows affected (0.00 sec)          

mariadb> CALL sys.statement_performance_analyzer('overall', NULL, 'with_runtimes_in_95th_percentile,with_full_table_scans');
+-----------------------------------------+
| Next Output                             |
+-----------------------------------------+
| Queries with Runtime in 95th Percentile |
+-----------------------------------------+
1 row in set (0.01 sec)

...

+-------------------------------------+
| Next Output                         |
+-------------------------------------+
| Top 10 Queries with Full Table Scan |
+-------------------------------------+
1 row in set (0.09 sec)

...


-- Use a custom view showing the top 10 query sorted by total execution time refreshing the view every minute using
-- the watch command in Linux.

mariadb> CREATE OR REPLACE VIEW mydb.my_statements AS
    -> SELECT sys.format_statement(DIGEST_TEXT) AS query,
    ->        SCHEMA_NAME AS db,
    ->        COUNT_STAR AS exec_count,
    ->        format_pico_time(SUM_TIMER_WAIT) AS total_latency,
    ->        format_pico_time(AVG_TIMER_WAIT) AS avg_latency,
    ->        ROUND(IFNULL(SUM_ROWS_SENT / NULLIF(COUNT_STAR, 0), 0)) AS rows_sent_avg,
    ->        ROUND(IFNULL(SUM_ROWS_EXAMINED / NULLIF(COUNT_STAR, 0), 0)) AS rows_examined_avg,
    ->        ROUND(IFNULL(SUM_ROWS_AFFECTED / NULLIF(COUNT_STAR, 0), 0)) AS rows_affected_avg,
    ->        DIGEST AS digest
    ->   FROM performance_schema.events_statements_summary_by_digest
    -> ORDER BY SUM_TIMER_WAIT DESC;
Query OK, 0 rows affected (0.01 sec)

mariadb> CALL sys.statement_performance_analyzer('create_table', 'mydb.digests_prev', NULL);
Query OK, 0 rows affected (0.10 sec)

shell$ watch -n 60 "mariadb sys --table -e \"
> SET @sys.statement_performance_analyzer.view = 'mydb.my_statements';
> SET @sys.statement_performance_analyzer.limit = 10;
> CALL statement_performance_analyzer('snapshot', NULL, NULL);
> CALL statement_performance_analyzer('delta', 'mydb.digests_prev', 'custom');
> CALL statement_performance_analyzer('save', 'mydb.digests_prev', NULL);
> \""

Every 60.0s: mariadb sys --table -e "                                                                                                   ...  Mon Dec 22 10:58:51 2014

+----------------------------------+
| Next Output                      |
+----------------------------------+
| Top 10 Queries Using Custom View |
+----------------------------------+
+-------------------+-------+------------+---------------+-------------+---------------+-------------------+-------------------+----------------------------------+
| query             | db    | exec_count | total_latency | avg_latency | rows_sent_avg | rows_examined_avg | rows_affected_avg | digest                           |
+-------------------+-------+------------+---------------+-------------+---------------+-------------------+-------------------+----------------------------------+
...
```

#### table_exists

##### Description
Tests whether the table specified in in_db and in_table exists either as a regular
table, or as a temporary table. The returned value corresponds to the table that
will be used, so if there's both a temporary and a permanent table with the given
name, then 'TEMPORARY' will be returned.

##### Parameters

* in_db (VARCHAR(64)): The database name to check for the existence of the table in.

* in_table (VARCHAR(64)): The name of the table to check the existence of.

* out_exists ENUM('', 'BASE TABLE', 'VIEW', 'TEMPORARY'):  The return value: whether the table exists. The value is one of:
   - ''           - the table does not exist neither as a base table, view, nor temporary table.
   - 'BASE TABLE' - the table name exists as a permanent base table table.
   - 'VIEW'       - the table name exists as a view.
   - 'TEMPORARY'  - the table name exists as a temporary table.

##### Example
```SQL
mariadb> CREATE DATABASE db1;
Query OK, 1 row affected (0.07 sec)

mariadb> use db1;
Database changed
mariadb> CREATE TABLE t1 (id INT PRIMARY KEY);
Query OK, 0 rows affected (0.08 sec)

mariadb> CREATE TABLE t2 (id INT PRIMARY KEY);
Query OK, 0 rows affected (0.08 sec)

mariadb> CREATE view v_t1 AS SELECT * FROM t1;
Query OK, 0 rows affected (0.00 sec)

mariadb> CREATE TEMPORARY TABLE t1 (id INT PRIMARY KEY);
Query OK, 0 rows affected (0.00 sec)

mariadb> CALL sys.table_exists('db1', 't1', @exists); SELECT @exists;
Query OK, 0 rows affected (0.00 sec)

+------------+
| @exists    |
+------------+
| TEMPORARY  |
+------------+
1 row in set (0.00 sec)

mariadb> CALL sys.table_exists('db1', 't2', @exists); SELECT @exists;
Query OK, 0 rows affected (0.00 sec)

+------------+
| @exists    |
+------------+
| BASE TABLE |
+------------+
1 row in set (0.01 sec)

mariadb> CALL sys.table_exists('db1', 'v_t1', @exists); SELECT @exists;
Query OK, 0 rows affected (0.00 sec)

+---------+
| @exists |
+---------+
| VIEW    |
+---------+
1 row in set (0.00 sec)

mariadb> CALL sys.table_exists('db1', 't3', @exists); SELECT @exists;
Query OK, 0 rows affected (0.01 sec)

+---------+
| @exists |
+---------+
|         |
+---------+
1 row in set (0.00 sec)
```