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create database explain_test_db;
use explain_test_db;
create table explain_test_table(c int);
create procedure explain_test_proc()
BEGIN
select * from explain_test_table;
END //
truncate table performance_schema.events_statements_summary_by_program;
call explain_test_proc();
c
====================================================================
Testing index for columns OBJECT_TYPE, OBJECT_SCHEMA, OBJECT_NAME
====================================================================
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_program NULL ref PRIMARY PRIMARY 1 const # 100.00 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_program NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_program NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "PROCEDURE";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_program NULL ref PRIMARY PRIMARY 1 const # 100.00 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "impossible"
and OBJECT_SCHEMA = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_program NULL ref PRIMARY PRIMARY 259 const,const # 100.00 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "PROCEDURE"
and OBJECT_SCHEMA = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_program NULL ref PRIMARY PRIMARY 259 const,const # 100.00 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "PROCEDURE"
and OBJECT_SCHEMA > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_program NULL ref PRIMARY PRIMARY 1 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "PROCEDURE"
and OBJECT_SCHEMA < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_program NULL ref PRIMARY PRIMARY 1 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "PROCEDURE"
and OBJECT_SCHEMA = "explain_test_db";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_program NULL ref PRIMARY PRIMARY 259 const,const # 100.00 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "impossible"
and OBJECT_SCHEMA = "impossible"
and OBJECT_NAME = "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_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "PROCEDURE"
and 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 NULL NULL NULL NULL NULL NULL NULL # NULL no matching row in const table
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "PROCEDURE"
and 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 events_statements_summary_by_program NULL ref PRIMARY PRIMARY 259 const,const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "PROCEDURE"
and 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 events_statements_summary_by_program NULL ref PRIMARY PRIMARY 259 const,const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "PROCEDURE"
and OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_proc";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_program NULL const PRIMARY PRIMARY 517 const,const,const # 100.00 NULL
############# Explain End #########################################
flush status;
select COUNT_STAR
from performance_schema.events_statements_summary_by_program
where OBJECT_TYPE = "PROCEDURE"
and OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_proc";
COUNT_STAR
#
OK: handler_read_key incremented
drop procedure explain_test_proc;
drop table explain_test_db.explain_test_table;
drop database explain_test_db;
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