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MWL#182: Explain running statements

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- Implement new approach to testing (the DBUG_EXECUTE_IF variant)
- add an 'evalp' mysqltest command that is like 'eval' except that
  it prints the original query.
- Fix select_describe() not to change join_tab[i]->type
- More tests
This commit is contained in:
Sergey Petrunya
2011-09-24 21:56:42 +04:00
parent d9045bce1d
commit 203bbfe569
7 changed files with 141 additions and 53 deletions
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43
mysql-test/r/show_explain.result
View File

@ -3,24 +3,37 @@ create table t0 (a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a int);
insert into t1 select A.a + 10*B.a + 100*C.a from t0 A, t0 B, t0 C;
alter table t1 add b int, add c int, add filler char(32);
update t1 set b=a, c=a, filler='fooo';
alter table t1 add key(a), add key(b);
show explain for 2*1000*1000*1000;
ERROR HY000: Unknown thread id: 2000000000
SHOW explain for thr2
show explain for (select max(a) from t0);
ERROR 42000: This version of MySQL doesn't yet support 'Usage of subqueries or stored function calls as part of this statement'
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
SHOW explain for thr1
show explain for $thr1;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
select get_lock('optimizer_done', 10);
get_lock('optimizer_done', 10)
1
select count(*) from t1 where a < 100000 and sleep(a*0 + release_lock('optimizer_done') +1);
select get_lock('optimizer_done', 100);
get_lock('optimizer_done', 100)
1
SHOW explain for thr2
set debug='d,show_explain_probe_1';
select count(*) from t1 where a < 100000;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 1000 Using where
select release_lock('optimizer_done');
release_lock('optimizer_done')
1
kill query thr2
1 SIMPLE t1 index a a 5 NULL 1000 Using where; Using index
count(*)
1000
set debug='d,show_explain_probe_1';
select max(c) from t1 where a < 10;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 10 Using where
max(c)
9
set optimizer_switch='index_condition_pushdown=on,mrr=on,mrr_sort_keys=on';
set debug='d,show_explain_probe_1';
explain select max(c) from t1 where a < 10;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 10 Using index condition; Rowid-ordered scan
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range a a 5 NULL 10 Using index condition; Rowid-ordered scan
drop table t0,t1;

65
mysql-test/t/show_explain.test
View File

@ -9,6 +9,9 @@ create table t0 (a int);
insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t1 (a int);
insert into t1 select A.a + 10*B.a + 100*C.a from t0 A, t0 B, t0 C;
alter table t1 add b int, add c int, add filler char(32);
update t1 set b=a, c=a, filler='fooo';
alter table t1 add key(a), add key(b);
#
# Try killing a non-existent thread
@ -16,7 +19,12 @@ insert into t1 select A.a + 10*B.a + 100*C.a from t0 A, t0 B, t0 C;
--error ER_NO_SUCH_THREAD
show explain for 2*1000*1000*1000;
--error ER_NOT_SUPPORTED_YET
show explain for (select max(a) from t0);
#
# Setup two threads and their ids
#
let $thr1=`select connection_id()`;
connect (con1, localhost, root,,);
connection con1;
@ -24,36 +32,47 @@ let $thr2=`select connection_id()`;
connection default;
# SHOW EXPLAIN FOR <idle thread>
echo SHOW explain for thr2;
--disable_query_log
--error ER_ERROR_WHEN_EXECUTING_COMMAND
eval show explain for $thr2;
--enable_query_log
evalp show explain for $thr2;
# SHOW EXPLAIN FOR <ourselves>
echo SHOW explain for thr1;
--disable_query_log
--error ER_ERROR_WHEN_EXECUTING_COMMAND
eval show explain for $thr1;
--enable_query_log
evalp show explain for $thr1;
# SHOW EXPLAIN FOR <running thread>
let $wait_condition= select State='show_explain_trap' from information_schema.processlist where id=$thr2;
#
# Test SHOW EXPLAIN for simple queries
#
connection con1;
select get_lock('optimizer_done', 10);
send select count(*) from t1 where a < 100000 and sleep(a*0 + release_lock('optimizer_done') +1);
connection default;
select get_lock('optimizer_done', 100);
echo SHOW explain for thr2;
--disable_query_log
eval show explain for $thr2;
--enable_query_log
select release_lock('optimizer_done');
--disable_query_log
eval kill query $thr2;
--enable_query_log
echo kill query thr2;
set debug='d,show_explain_probe_1';
send select count(*) from t1 where a < 100000;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug='d,show_explain_probe_1';
send select max(c) from t1 where a < 10;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
# We can catch EXPLAIN, too.
set optimizer_switch='index_condition_pushdown=on,mrr=on,mrr_sort_keys=on';
set debug='d,show_explain_probe_1';
send explain select max(c) from t1 where a < 10;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
#insert into t1 values ('one'),('two'),('three');
## TODO: Test this: multiple SHOW EXPLAIN calls in course of running of one select
##