1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
|
drop table if exists t0, t1;
select * from performance_schema.setup_instruments where name like '%show_explain%';
NAME ENABLED TIMED
wait/synch/cond/sql/show_explain YES YES
stage/sql/show explain YES YES
statement/sql/show_explain YES YES
# We've got no instances
select * from performance_schema.cond_instances where name like '%show_explain%';
NAME OBJECT_INSTANCE_BEGIN
# Check out if our cond is hit.
create table t0 (a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
connect con1, localhost, root,,;
connection con1;
connection default;
connection con1;
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select count(*) from t0 where a < 100000;
connection default;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using where
Warnings:
Note 1003 select count(*) from t0 where a < 100000
connection con1;
count(*)
10
set debug_dbug='';
select event_name
from performance_schema.events_waits_history_long
where event_name='wait/synch/cond/sql/show_explain';
event_name
wait/synch/cond/sql/show_explain
drop table t0;
|
