mariadb/mysql-test/r/show_explain.result

drop table if exists t0, t1, t2, t3, t4;
drop view if exists v1;
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 (select max(a) from t0);
ERROR 42000: This version of MariaDB 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;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
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	index	a	a	5	NULL	1000	Using where; Using index
Warnings:
Note	1003	select count(*) from t1 where a < 100000
count(*)
1000
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
Warnings:
Note	1003	select max(c) from t1 where a < 10
max(c)
9
# We can catch EXPLAIN, too.
set @show_expl_tmp= @@optimizer_switch;
set optimizer_switch='index_condition_pushdown=on,mrr=on,mrr_sort_keys=on';
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
Warnings:
Note	1003	explain select max(c) from t1 where a < 10
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
set optimizer_switch= @show_expl_tmp;
# UNION, first branch 
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
explain select a from t0 A union select a+1 from t0 B;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	
2	UNION	B	ALL	NULL	NULL	NULL	NULL	10	
NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1003	explain select a from t0 A union select a+1 from t0 B
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	
2	UNION	B	ALL	NULL	NULL	NULL	NULL	10	
NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
# UNION, second branch
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
explain select a from t0 A union select a+1 from t0 B;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	
2	UNION	B	ALL	NULL	NULL	NULL	NULL	10	
NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1003	explain select a from t0 A union select a+1 from t0 B
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	
2	UNION	B	ALL	NULL	NULL	NULL	NULL	10	
NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
# Uncorrelated  subquery, select
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 B) from t0 A where a<1;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
2	SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	
Warnings:
Note	1003	select a, (select max(a) from t0 B) from t0 A where a<1
a	(select max(a) from t0 B)
0	9
# Uncorrelated  subquery, explain
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
explain select a, (select max(a) from t0 B) from t0 A where a<1;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
2	SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	
Warnings:
Note	1003	explain select a, (select max(a) from t0 B) from t0 A where a<1
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	10	Using where
2	SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	10	
# correlated  subquery, select
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	a	ALL	NULL	NULL	NULL	NULL	10	Using where
2	DEPENDENT SUBQUERY	b	ALL	NULL	NULL	NULL	NULL	10	Using where
Warnings:
Note	1003	select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1
a	(select max(a) from t0 b where b.a+a.a<10)
0	9
# correlated  subquery, explain
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	a	ALL	NULL	NULL	NULL	NULL	10	Using where
2	DEPENDENT SUBQUERY	b	ALL	NULL	NULL	NULL	NULL	10	Using where
Warnings:
Note	1003	select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1
a	(select max(a) from t0 b where b.a+a.a<10)
0	9
# correlated  subquery, select, while inside the subquery
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	a	ALL	NULL	NULL	NULL	NULL	10	Using where
2	DEPENDENT SUBQUERY	b	ALL	NULL	NULL	NULL	NULL	10	Using where
Warnings:
Note	1003	select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1
a	(select max(a) from t0 b where b.a+a.a<10)
0	9
# correlated  subquery, explain, while inside the subquery
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	a	ALL	NULL	NULL	NULL	NULL	10	Using where
2	DEPENDENT SUBQUERY	b	ALL	NULL	NULL	NULL	NULL	10	Using where
Warnings:
Note	1003	select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1
a	(select max(a) from t0 b where b.a+a.a<10)
0	9
# correlated  subquery, explain, while inside the subquery
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
select a, (select max(a) from t0 b where b.a+a.a<10) from t0 a where a<1;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
a	(select max(a) from t0 b where b.a+a.a<10)
0	9
# Try to do SHOW EXPLAIN for a query that runs a  SET command:
#   I've found experimentally that select_id==2 here...
# 
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
set @foo= (select max(a) from t0 where sin(a) >0);
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
#
# Attempt SHOW EXPLAIN for an UPDATE
#
create table t2 as select a as a, a as dummy from t0 limit 2;
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
update t2 set dummy=0 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
drop table t2;
#
# Attempt SHOW EXPLAIN for a DELETE
# 
create table t2 as select a as a, a as dummy from t0 limit 2;
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
delete from t2 where (select max(a) from t0 where t2.a + t0.a <3) >3 ;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
drop table t2;
#
# Multiple SHOW EXPLAIN calls for one select 
# 
create table t2 as select a as a, a as dummy from t0 limit 3;
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_start';
select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	
2	DEPENDENT SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where
Warnings:
Note	1003	select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	
2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Query plan already deleted
Warnings:
Note	1003	select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	
2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Query plan already deleted
Warnings:
Note	1003	select t2.a, ((select max(a) from t0 where t2.a + t0.a <3) >3) as SUBQ from t2
a	SUBQ
0	0
1	0
2	0
drop table t2;
#
# SHOW EXPLAIN for SELECT ... ORDER BY with "Using filesort"
#
explain select * from t0 order by a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	Using filesort
set debug_dbug='d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
select * from t0 order by a;
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 filesort
Warnings:
Note	1003	select * from t0 order by a
a
0
1
2
3
4
5
6
7
8
9
#
# SHOW EXPLAIN for SELECT ... with "Using temporary"
#
explain select distinct a from t0;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	Using temporary
set debug_dbug='d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
select distinct a from t0;
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 temporary
Warnings:
Note	1003	select distinct a from t0
a
0
1
2
3
4
5
6
7
8
9
#
# SHOW EXPLAIN for SELECT ... with "Using temporary; Using filesort"
#
explain select distinct a from t0;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	10	Using temporary
set debug_dbug='d,show_explain_probe_join_exec_start';
set @show_explain_probe_select_id=1;
select distinct a from t0;
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 temporary
Warnings:
Note	1003	select distinct a from t0
a
0
1
2
3
4
5
6
7
8
9
set debug_dbug='';
#
# MDEV-238: SHOW EXPLAIN: Server crashes in JOIN::print_explain with FROM subquery and GROUP BY
#
CREATE TABLE t2 ( a INT );
INSERT INTO t2 VALUES (1),(2),(1),(4),(2);
explain SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	Using temporary; Using filesort
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	Using join buffer (flat, BNL join)
set debug_dbug='d,show_explain_in_find_all_keys';
SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a;
# FIXED by "conservative assumptions about when QEP is available" fix:
#    NOTE: current code will not show "Using join buffer": 
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
a
1
2
4
set debug_dbug='';
DROP TABLE t2;
#
# MDEV-239: Assertion `field_types == 0 ... ' failed in Protocol_text::store(double, uint32, String*) with 
#          SHOW EXPLAIN over EXPLAIN EXTENDED
#
CREATE TABLE t2 (a INT);
INSERT INTO t2 VALUES (1),(2),(1),(4),(2);
EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using temporary; Using filesort
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using join buffer (flat, BNL join)
Warnings:
Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` join `test`.`t2` group by `test`.`t2`.`a`
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a ;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	Using temporary; Using filesort
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	Using join buffer (flat, BNL join)
Warnings:
Note	1003	EXPLAIN EXTENDED SELECT alias.a FROM t2, ( SELECT * FROM t2 ) AS alias GROUP BY alias.a
id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using temporary; Using filesort
1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	100.00	Using join buffer (flat, BNL join)
Warnings:
Note	1003	select `test`.`t2`.`a` AS `a` from `test`.`t2` join `test`.`t2` group by `test`.`t2`.`a`
set debug_dbug='';
DROP TABLE t2;
#
# MDEV-240: SHOW EXPLAIN: Assertion `this->optimized == 2' failed in 
# JOIN::print_explain on query with a JOIN, TEMPTABLE view,
#          
CREATE TABLE t3 (a INT);
CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t3;
INSERT INTO t3 VALUES (8);
CREATE TABLE t2 (b INT);
INSERT INTO t2 VALUES (4),(5),(6),(7),(8),(9);
explain SELECT * FROM v1, t2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	1	
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	6	
2	DERIVED	t3	system	NULL	NULL	NULL	NULL	1	
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_join_exec_end';
SELECT * FROM v1, t2;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
a	b
8	4
8	5
8	6
8	7
8	8
8	9
set debug_dbug='';
DROP VIEW v1;
DROP TABLE t2, t3;
#
# MDEV-267: SHOW EXPLAIN: Server crashes in JOIN::print_explain on most of queries
#
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
select sleep(1);
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
Warnings:
Note	1003	select sleep(1)
sleep(1)
0
set debug_dbug='';
#
# Same as above, but try another reason for JOIN to be degenerate
#
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
select * from t0 where 1>10;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
a
set debug_dbug='';
#
# Same as above, but try another reason for JOIN to be degenerate (2)
#
create table t3(a int primary key);
insert into t3 select a from t0;
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
select * from t0,t3 where t3.a=112233;
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
a	a
set debug_dbug='';
drop table t3;
#
# MDEV-270: SHOW EXPLAIN: server crashes in JOIN::print_explain on a query with 
#           select tables optimized away
#
CREATE TABLE t2 (pk INT PRIMARY KEY, a INT ) ENGINE=MyISAM;
INSERT INTO t2 VALUES 
(1,4),(2,62),(3,7),(4,1),(5,0),(6,7),(7,7),(8,1),(9,7),(10,1),
(11,5),(12,2),(13,0),(14,1),(15,8),(16,1),(17,1),(18,9),(19,1),(20,5) ;
explain SELECT * FROM t2 WHERE a = 
(SELECT MAX(a) FROM t2 
WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	20	Using where
2	SUBQUERY	t2	const	PRIMARY	PRIMARY	4	const	1	Using where
3	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
set @show_explain_probe_select_id=2;
set debug_dbug='d,show_explain_probe_do_select';
SELECT * FROM t2 WHERE a = 
(SELECT MAX(a) FROM t2 
WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
);
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	20	Using where
2	SUBQUERY	t2	const	PRIMARY	PRIMARY	4	const	1	Using where
3	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
Warnings:
Note	1003	SELECT * FROM t2 WHERE a = 
(SELECT MAX(a) FROM t2 
WHERE pk= (SELECT MAX(pk) FROM t2 WHERE pk = 3)
)
pk	a
3	7
6	7
7	7
9	7
set debug_dbug='';
drop table t2;
#
# MDEV-273: SHOW EXPLAIN: server crashes in JOIN::print_explain on a query with impossible WHERE
#
CREATE TABLE t2 (a1 INT, KEY(a1)) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(4),(6),(7),(1),(0),(7),(7),(1),(7),(1),
(5),(2),(0),(1),(8),(1),(1),(9),(1),(5);
CREATE TABLE t3 (b1 INT) ENGINE=MyISAM;
INSERT INTO t3 VALUES
(4),(5),(8),(4),(8),(2),(9),(6),(4),(8),
(3),(5),(9),(6),(8),(3),(2),(6),(3),(1),
(4),(3),(1),(7),(0),(0),(9),(5),(9),(0),
(2),(2),(5),(9),(1),(4),(8),(6),(5),(5),
(1),(7),(2),(8),(9),(3),(2),(6),(6),(5),
(4),(3),(2),(7),(4),(6),(0),(8),(5),(8),
(2),(9),(7),(5),(7),(0),(4),(3),(1),(0),
(6),(2),(8),(3),(7),(3),(5),(5),(1),(2),
(1),(7),(1),(9),(9),(8),(3);
CREATE TABLE t4 (c1 INT) ENGINE=MyISAM;
EXPLAIN
SELECT count(*) FROM t2, t3
WHERE a1 < ALL ( 
SELECT a1 FROM t2
WHERE a1 IN ( SELECT a1 FROM t2, t4 )
);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	index	NULL	a1	5	NULL	20	Using where; Using index
1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	87	Using join buffer (flat, BNL join)
2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_do_select';
SELECT count(*) FROM t2, t3
WHERE a1 < ALL ( 
SELECT a1 FROM t2
WHERE a1 IN ( SELECT a1 FROM t2, t4 )
);
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t2	index	NULL	a1	5	NULL	20	Using where; Using index
1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	87	Using join buffer (flat, BNL join)
2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
Warnings:
Note	1003	SELECT count(*) FROM t2, t3
WHERE a1 < ALL ( 
SELECT a1 FROM t2
WHERE a1 IN ( SELECT a1 FROM t2, t4 )
)
count(*)
1740
set debug_dbug='';
drop table t2, t3, t4;
#
# MDEV-275: SHOW EXPLAIN: server crashes in JOIN::print_explain with IN subquery and aggregate function
#
CREATE TABLE t2 ( `pk` INT NOT NULL PRIMARY KEY, `a1` INT NOT NULL, KEY(`a1`)) ENGINE=MyISAM;
INSERT INTO t2 VALUES 
(1,5),(2,4),(3,6),(4,9),(5,2),(6,8),(7,4),(8,8),(9,0),(10,43),
(11,23),(12,3),(13,45),(14,16),(15,2),(16,33),(17,2),(18,5),(19,9),(20,2);
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_end';
SELECT * FROM t2 WHERE (5, 78) IN (SELECT `a1`, MAX(`a1`) FROM t2 GROUP BY `a1`);
show explain for $thr2;
ERROR HY000: Error when executing command SHOW EXPLAIN: Target is not running EXPLAINable command
pk	a1
set debug_dbug='';
DROP TABLE t2;
DROP TABLE t1;
#
# MDEV-305: SHOW EXPLAIN: ref returned by SHOW EXPLAIN is different from the normal EXPLAIN ('const' vs empty string)
#
CREATE TABLE t1(a INT, KEY(a));
INSERT INTO t1 VALUES (3),(1),(5),(1);
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
SELECT 'test' FROM t1 WHERE a=1;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	a	a	5	const	1	Using index
Warnings:
Note	1003	SELECT 'test' FROM t1 WHERE a=1
test
test
test
set debug_dbug='';
DROP TABLE t1;
#
# MDEV-299: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN changes back and forth during query execution
#
create table t1 (key1 int, col1 int, col2 int, filler char(100), key(key1));
insert into t1 select A.a+ 10 * B.a, 10, 10, 'filler-data' from t0 A, t0 B;
update t1 set col1=3, col2=10 where key1=1;
update t1 set col1=3, col2=1000 where key1=2;
update t1 set col1=3, col2=10 where key1=3;
update t1 set col1=3, col2=1000 where key1=4;
set @tmp_mdev299_jcl= @@join_cache_level;
set join_cache_level=0;
explain select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	A	ALL	NULL	NULL	NULL	NULL	100	Using where
1	SIMPLE	B	ALL	key1	NULL	NULL	NULL	100	Range checked for each record (index map: 0x1)
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_test_if_quick_select';
select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	A	ALL	NULL	NULL	NULL	NULL	100	Using where
1	SIMPLE	B	ALL	key1	NULL	NULL	NULL	100	Range checked for each record (index map: 0x1)
Warnings:
Note	1003	select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	A	ALL	NULL	NULL	NULL	NULL	100	Using where
1	SIMPLE	B	ALL	key1	NULL	NULL	NULL	100	Range checked for each record (index map: 0x1)
Warnings:
Note	1003	select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	A	ALL	NULL	NULL	NULL	NULL	100	Using where
1	SIMPLE	B	ALL	key1	NULL	NULL	NULL	100	Range checked for each record (index map: 0x1)
Warnings:
Note	1003	select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	A	ALL	NULL	NULL	NULL	NULL	100	Using where
1	SIMPLE	B	ALL	key1	NULL	NULL	NULL	100	Range checked for each record (index map: 0x1)
Warnings:
Note	1003	select count(*) from t1 A, t1 B where B.key1 < A.col2 and A.col1=3 AND B.col2 + 1 < 100
count(*)
212
set debug_dbug='';
drop table t1;
#
# MDEV-297: SHOW EXPLAIN: Server gets stuck until timeout occurs while
#           executing SHOW INDEX and SHOW EXPLAIN in parallel
#
CREATE TABLE t1(a INT, b INT, c INT, KEY(a), KEY(b), KEY(c));
INSERT INTO t1 (a) VALUES (3),(1),(5),(1);
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
SHOW INDEX FROM t1;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	STATISTICS	ALL	NULL	NULL	NULL	NULL	NULL	Skip_open_table; Scanned all databases
Warnings:
Note	1003	SHOW INDEX FROM t1
Table	Non_unique	Key_name	Seq_in_index	Column_name	Collation	Cardinality	Sub_part	Packed	Null	Index_type	Comment	Index_comment
t1	1	a	1	a	A	NULL	NULL	NULL	YES	BTREE		
t1	1	b	1	b	A	NULL	NULL	NULL	YES	BTREE		
t1	1	c	1	c	A	NULL	NULL	NULL	YES	BTREE		
set debug_dbug='';
DROP TABLE t1;
#
# MDEV-324: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN for a query with TEMPTABLE view 
#           loses 'DERIVED' line on the way without saying that the plan was already deleted
#
CREATE TABLE t1 (a INT);
INSERT INTO t1 VALUES (1),(2);
CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
EXPLAIN SELECT a + 1 FROM v1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	
set debug_dbug='d,show_explain_probe_join_tab_preread';
set @show_explain_probe_select_id=1;
SELECT a + 1 FROM v1;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Query plan already deleted
Warnings:
Note	1003	SELECT a + 1 FROM v1
a + 1
2
3
set debug_dbug='';
DROP VIEW v1;
DROP TABLE t1;
#
# MDEV-323: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN loses 
#            'UNION RESULT' line on the way without saying that the plan was already deleted
#
CREATE TABLE t1 (a INT);
INSERT INTO t1 VALUES (4),(6);
EXPLAIN 
SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
set debug_dbug='d,show_explain_probe_union_read';
SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 );
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1003	SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 )
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
Warnings:
Note	1003	SELECT a FROM t1 WHERE a IN ( SELECT 1+SLEEP(0.01) UNION SELECT 2 )
a
set debug_dbug='';
DROP TABLE t1;
#
# MDEV-327: SHOW EXPLAIN: Different select_type in plans produced by SHOW EXPLAIN 
#           and standard EXPLAIN: 'SUBQUERY' vs 'DEPENDENT SUBQUERY'
#
CREATE TABLE t1 (a INT) ENGINE=Aria;
INSERT INTO t1 VALUES
(4),(6),(3),(5),(3),(246),(2),(9),(3),(8),
(1),(8),(8),(5),(7),(5),(1),(6),(2),(9);
CREATE TABLE t2 (b INT) ENGINE=Aria;
INSERT INTO t2 VALUES
(1),(7),(4),(7),(0),(2),(9),(4),(0),(9),
(1),(3),(8),(8),(18),(84),(6),(3),(6),(6);
EXPLAIN
SELECT * FROM t1, ( SELECT * FROM t2 ) AS alias
WHERE a < ALL ( SELECT b FROM t1, t2 WHERE a = b );
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	20	Using where
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	20	
3	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	20	
3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	20	Using where
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
SELECT * FROM t1, ( SELECT * FROM t2 ) AS alias
WHERE a < ALL ( SELECT b FROM t1, t2 WHERE a = b );
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	20	Using where
1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	20	
3	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	20	
3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	20	Using where
Warnings:
Note	1003	SELECT * FROM t1, ( SELECT * FROM t2 ) AS alias
WHERE a < ALL ( SELECT b FROM t1, t2 WHERE a = b )
a	b
set debug_dbug='';
DROP TABLE t1, t2;
# 
#  Test that SHOW EXPLAIN will print 'Distinct'.
#
CREATE TABLE t1 (a int(10) unsigned not null primary key,b int(10) unsigned);
INSERT INTO t1 VALUES (1,1),(2,1),(3,1),(4,1);
CREATE TABLE t3 (a int(10) unsigned, key(A), b text);
INSERT INTO t3 VALUES (1,'1'),(2,'2');
create temporary table t4 select * from t3;
insert into t3 select * from t4;
insert into t4 select * from t3;
insert into t3 select * from t4;
insert into t4 select * from t3;
insert into t3 select * from t4;
insert into t4 select * from t3;
insert into t3 select * from t4;
explain select distinct t1.a from t1,t3 where t1.a=t3.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	PRIMARY	PRIMARY	4	NULL	4	Using index; Using temporary
1	SIMPLE	t3	ref	a	a	5	test.t1.a	7	Using index; Distinct
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select distinct t1.a from t1,t3 where t1.a=t3.a;
show explain for $thr2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	index	PRIMARY	PRIMARY	4	NULL	4	Using index; Using temporary
1	SIMPLE	t3	ref	a	a	5	test.t1.a	7	Using index; Distinct
Warnings:
Note	1003	select distinct t1.a from t1,t3 where t1.a=t3.a
a
1
2
set debug_dbug='';
drop table t1,t3,t4;
#
# ----------  SHOW EXPLAIN and permissions -----------------
#
grant ALL on test.* to test2@localhost;
#
#  First, make sure that user 'test2' cannot do SHOW EXPLAIN on us
#
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select * from t0 where a < 3;
show explain for $thr2;
ERROR 42000: Access denied; you need (at least one of) the PROCESSLIST privilege(s) for this operation
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 * from t0 where a < 3
a
0
1
2
set debug_dbug='';
#
# Unfortunately, our test setup doesn't allow to check that test2
# can do SHOW EXPLAIN on his own queries. This is because SET debug_dbug
# requires SUPER privilege. Giving SUPER to test2 will make the test
# meaningless
#
#
# Now, grant test2 a PROCESSLIST permission, and see that he's able to observe us 
#
grant process on *.* to test2@localhost;
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
select * from t0 where a < 3;
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 * from t0 where a < 3
a
0
1
2
set debug_dbug='';
revoke all privileges on test.* from test2@localhost;
drop user test2@localhost;
drop table t0;