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create user foo@localhost;
grant ALL on *.* to foo@localhost;
====================================================================
Testing index for columns USER , EVENT_NAME
====================================================================
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_user_by_event_name
where USER = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_user_by_event_name NULL ref USER USER 129 const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_user_by_event_name
where USER > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_user_by_event_name NULL ALL USER NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_user_by_event_name
where USER < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_user_by_event_name NULL ALL USER NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_user_by_event_name
where USER = "foo";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_user_by_event_name NULL ref USER USER 129 const # 100.00 NULL
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_user_by_event_name
where USER = "impossible"
and EVENT_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_user_by_event_name
where USER = "foo"
and EVENT_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_user_by_event_name
where USER = "foo"
and EVENT_NAME > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_user_by_event_name NULL ref USER USER 129 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_user_by_event_name
where USER = "foo"
and EVENT_NAME < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_user_by_event_name NULL ref USER USER 129 const # 33.33 Using where
############ Explain for Query ####################################
explain select COUNT_STAR
from performance_schema.events_statements_summary_by_user_by_event_name
where USER = "foo"
and EVENT_NAME = "statement/sql/select";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_summary_by_user_by_event_name NULL const USER USER 643 const,const # 100.00 NULL
############# Explain End #########################################
flush status;
select COUNT_STAR
from performance_schema.events_statements_summary_by_user_by_event_name
where USER = "foo"
and EVENT_NAME = "statement/sql/select";
COUNT_STAR
#
OK: handler_read_key incremented
drop user foo@localhost;
|
