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select connection_id() into @conid;
truncate table performance_schema.events_statements_history;
select 1;
1
1
====================================================================
Testing index for columns THREAD_ID, EVENT_ID
====================================================================
############ Explain for Query ####################################
explain select END_EVENT_ID
from performance_schema.events_statements_history
where THREAD_ID = "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_history NULL ref PRIMARY PRIMARY 8 const # 100.00 Using where
############ Explain for Query ####################################
explain select END_EVENT_ID
from performance_schema.events_statements_history
where THREAD_ID > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_history NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select END_EVENT_ID
from performance_schema.events_statements_history
where THREAD_ID < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_history NULL ALL PRIMARY NULL NULL NULL # 33.33 Using where
############ Explain for Query ####################################
explain select END_EVENT_ID
from performance_schema.events_statements_history
where THREAD_ID = @tid_default;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_history NULL ref PRIMARY PRIMARY 8 const # 100.00 NULL
############ Explain for Query ####################################
explain select END_EVENT_ID
from performance_schema.events_statements_history
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 NULL NULL NULL NULL NULL NULL NULL # NULL no matching row in const table
############ Explain for Query ####################################
explain select END_EVENT_ID
from performance_schema.events_statements_history
where THREAD_ID = @tid_default
and EVENT_ID = "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 END_EVENT_ID
from performance_schema.events_statements_history
where THREAD_ID = @tid_default
and EVENT_ID > "impossible";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_history NULL ref PRIMARY PRIMARY 8 const # 33.33 Using where
############ Explain for Query ####################################
explain select END_EVENT_ID
from performance_schema.events_statements_history
where THREAD_ID = @tid_default
and EVENT_ID < "2";
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_history NULL ref PRIMARY PRIMARY 8 const # 33.33 Using where
############ Explain for Query ####################################
explain select END_EVENT_ID
from performance_schema.events_statements_history
where THREAD_ID = @tid_default
and EVENT_ID = @eid_default;
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
1 SIMPLE events_statements_history NULL const PRIMARY PRIMARY 16 const,const # 100.00 NULL
############# Explain End #########################################
flush status;
select END_EVENT_ID
from performance_schema.events_statements_history
where THREAD_ID = @tid_default
and EVENT_ID = @eid_default;
END_EVENT_ID
#
OK: handler_read_key incremented
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