create database explain_test_db;
use explain_test_db;
create table explain_test_table(c int) engine = XENGINE;
create procedure explain_test_proc()
BEGIN
select * from explain_test_table;
END //
call explain_test_proc();
c
insert into performance_schema.setup_objects values ('PROCEDURE',
'explain_test_db', 'explain_test_proc', 'YES', 'YES');

====================================================================
Testing index for columns OBJECT_TYPE, OBJECT_SCHEMA, OBJECT_NAME
====================================================================
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
where OBJECT_TYPE = "impossible";
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	setup_objects	NULL	ref	OBJECT	OBJECT	1	const	#	100.00	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
where OBJECT_TYPE > "impossible";
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	setup_objects	NULL	ALL	OBJECT	NULL	NULL	NULL	#	33.33	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
where OBJECT_TYPE < "2";
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	setup_objects	NULL	ALL	OBJECT	NULL	NULL	NULL	#	33.33	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
where OBJECT_TYPE = "PROCEDURE";
id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	setup_objects	NULL	ref	OBJECT	OBJECT	1	const	#	100.00	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
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	setup_objects	NULL	ref	OBJECT	OBJECT	260	const,const	#	100.00	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
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	setup_objects	NULL	ref	OBJECT	OBJECT	260	const,const	#	100.00	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
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	setup_objects	NULL	ref	OBJECT	OBJECT	1	const	#	33.33	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
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	setup_objects	NULL	ref	OBJECT	OBJECT	1	const	#	33.33	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
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	setup_objects	NULL	ref	OBJECT	OBJECT	260	const,const	#	100.00	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
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 ENABLED
from performance_schema.setup_objects
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 ENABLED
from performance_schema.setup_objects
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	setup_objects	NULL	ref	OBJECT	OBJECT	260	const,const	#	33.33	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
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	setup_objects	NULL	ref	OBJECT	OBJECT	260	const,const	#	33.33	Using where
############ Explain for Query ####################################
explain select ENABLED
from performance_schema.setup_objects
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	setup_objects	NULL	const	OBJECT	OBJECT	518	const,const,const	#	100.00	NULL
############# Explain End #########################################
flush status;
select ENABLED
from performance_schema.setup_objects
where OBJECT_TYPE = "PROCEDURE"
and OBJECT_SCHEMA = "explain_test_db"
and OBJECT_NAME = "explain_test_proc";
ENABLED
#
OK: handler_read_key incremented
delete from performance_schema.setup_objects where object_schema = 'explain_test_db';
drop table explain_test_db.explain_test_table;
drop database explain_test_db;