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# Connection con1
create database explain_test_db;
create table explain_test_db.explain_test_table(a int, b int, PRIMARY KEY (a, b)) engine=innodb
PARTITION BY RANGE( a )
SUBPARTITION BY HASH( b ) (
PARTITION p0 VALUES LESS THAN (1990) (
SUBPARTITION s0,
SUBPARTITION s1
),
PARTITION p1 VALUES LESS THAN (2000) (
SUBPARTITION s2,
SUBPARTITION s3
),
PARTITION p2 VALUES LESS THAN MAXVALUE (
SUBPARTITION s4,
SUBPARTITION s5
)
);
insert into explain_test_db.explain_test_table values (1, 100), (1995, 200);
start transaction;
update explain_test_db.explain_test_table set b=b+1;
# Connection default
select ENGINE, ENGINE_LOCK_ID, ENGINE_TRANSACTION_ID, THREAD_ID, EVENT_ID,
PARTITION_NAME, SUBPARTITION_NAME
from performance_schema.data_locks
where OBJECT_NAME = 'explain_test_table'
and LOCK_TYPE = 'RECORD' and LOCK_DATA = '1, 100'
into @engine, @lock_id, @trx_id, @thread_id, @event_id, @part, @subpart;
select @engine is null,
@lock_id is null,
@trx_id is null,
@thread_id is null,
@event_id is null,
@part, @subpart;
@engine is null @lock_id is null @trx_id is null @thread_id is null @event_id is null @part @subpart
0 0 0 0 0 p0 s0
====================================================================
Testing index for columns ENGINE_LOCK_ID, ENGINE
====================================================================
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_LOCK_ID = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref PRIMARY PRIMARY 514 const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_LOCK_ID > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_LOCK_ID < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_LOCK_ID = @lock_id;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref PRIMARY PRIMARY 514 const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_LOCK_ID = "impossible"
and ENGINE = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL # NULL no matching row in const table
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_LOCK_ID = @lock_id
and ENGINE = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL # NULL no matching row in const table
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_LOCK_ID = @lock_id
and ENGINE > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref PRIMARY PRIMARY 514 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_LOCK_ID = @lock_id
and ENGINE < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref PRIMARY PRIMARY 514 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_LOCK_ID = @lock_id
and ENGINE = @engine;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL const PRIMARY PRIMARY 644 const,const # 100.00 NULL
############# Explain End #########################################
flush status;
select COUNT(*)
from performance_schema.data_locks
where ENGINE_LOCK_ID = @lock_id
and ENGINE = @engine;
COUNT(*)
#
OK: handler_read_key incremented
====================================================================
Testing index for columns ENGINE_TRANSACTION_ID, ENGINE
====================================================================
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_TRANSACTION_ID = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref ENGINE_TRANSACTION_ID ENGINE_TRANSACTION_ID 9 const # 100.00 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_TRANSACTION_ID > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ALL ENGINE_TRANSACTION_ID NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_TRANSACTION_ID < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ALL ENGINE_TRANSACTION_ID NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_TRANSACTION_ID = @trx_id;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref ENGINE_TRANSACTION_ID ENGINE_TRANSACTION_ID 9 const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_TRANSACTION_ID = "impossible"
and ENGINE = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref ENGINE_TRANSACTION_ID ENGINE_TRANSACTION_ID 139 const,const # 100.00 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_TRANSACTION_ID = @trx_id
and ENGINE = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref ENGINE_TRANSACTION_ID ENGINE_TRANSACTION_ID 139 const,const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_TRANSACTION_ID = @trx_id
and ENGINE > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref ENGINE_TRANSACTION_ID ENGINE_TRANSACTION_ID 9 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_TRANSACTION_ID = @trx_id
and ENGINE < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref ENGINE_TRANSACTION_ID ENGINE_TRANSACTION_ID 9 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where ENGINE_TRANSACTION_ID = @trx_id
and ENGINE = @engine;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref ENGINE_TRANSACTION_ID ENGINE_TRANSACTION_ID 139 const,const # 100.00 NULL
############# Explain End #########################################
flush status;
select COUNT(*)
from performance_schema.data_locks
where ENGINE_TRANSACTION_ID = @trx_id
and ENGINE = @engine;
COUNT(*)
#
OK: handler_read_key incremented
====================================================================
Testing index for columns THREAD_ID, EVENT_ID
====================================================================
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where THREAD_ID = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref THREAD_ID THREAD_ID 9 const # 100.00 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where THREAD_ID > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ALL THREAD_ID NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where THREAD_ID < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ALL THREAD_ID NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where THREAD_ID = @thread_id;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref THREAD_ID THREAD_ID 9 const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where THREAD_ID = "impossible"
and EVENT_ID = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref THREAD_ID THREAD_ID 18 const,const # 100.00 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where THREAD_ID = @thread_id
and EVENT_ID = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref THREAD_ID THREAD_ID 18 const,const # 100.00 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where THREAD_ID = @thread_id
and EVENT_ID > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref THREAD_ID THREAD_ID 9 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where THREAD_ID = @thread_id
and EVENT_ID < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref THREAD_ID THREAD_ID 9 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where THREAD_ID = @thread_id
and EVENT_ID = @event_id;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref THREAD_ID THREAD_ID 18 const,const # 100.00 NULL
############# Explain End #########################################
flush status;
select COUNT(*)
from performance_schema.data_locks
where THREAD_ID = @thread_id
and EVENT_ID = @event_id;
COUNT(*)
#
OK: handler_read_key incremented
====================================================================
Testing index for columns OBJECT_SCHEMA, OBJECT_NAME, PARTITION_NAME, SUBPARTITION_NAME
====================================================================
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 259 const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ALL OBJECT_SCHEMA NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ALL OBJECT_SCHEMA NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 259 const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "impossible"
and OBJECT_NAME = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 518 const,const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 518 const,const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 259 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 259 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_table";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 518 const,const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "impossible"
and OBJECT_NAME = "impossible"
and PARTITION_NAME = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 777 const,const,const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_table"
and PARTITION_NAME = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 777 const,const,const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_table"
and PARTITION_NAME > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 518 const,const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_table"
and PARTITION_NAME < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 518 const,const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_table"
and PARTITION_NAME = @part;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 777 const,const,const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "impossible"
and OBJECT_NAME = "impossible"
and PARTITION_NAME = "impossible"
and SUBPARTITION_NAME = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 1036 const,const,const,const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_table"
and PARTITION_NAME = @part
and SUBPARTITION_NAME = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 1036 const,const,const,const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_table"
and PARTITION_NAME = @part
and SUBPARTITION_NAME > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 777 const,const,const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_table"
and PARTITION_NAME = @part
and SUBPARTITION_NAME < "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 777 const,const,const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_table"
and PARTITION_NAME = @part
and SUBPARTITION_NAME = @subpart;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE data_locks NULL ref OBJECT_SCHEMA OBJECT_SCHEMA 1036 const,const,const,const # 100.00 NULL
############# Explain End #########################################
flush status;
select COUNT(*)
from performance_schema.data_locks
where OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_table"
and PARTITION_NAME = @part
and SUBPARTITION_NAME = @subpart;
COUNT(*)
#
OK: handler_read_key incremented
# Connection con1
commit;
drop table explain_test_db.explain_test_table;
drop database explain_test_db;
# Connection default
|
