SHOW EXPLAIN for MariaDB

- Support [SHOW] EXPLAIN UPDATE (needs code cleanup).

1 files changed, 52 insertions, 1 deletions

diff --git a/mysql-test/r/explain_non_select.result b/mysql-test/r/explain_non_select.result
index aa592f0b198..1c8e444c4b9 100644
--- a/mysql-test/r/explain_non_select.result
+++ b/mysql-test/r/explain_non_select.result
@@ -38,7 +38,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 explain delete from t1 where a < (select max(a) from t0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	range	a	a	5	NULL	1	Using where
-2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Query plan already deleted
+2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	8	
 explain delete from t1 where a < (select max(a) from t0 where a < t1.b);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	512	Using where
@@ -51,3 +51,54 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	8	Using where
 1	SIMPLE	t1	ref	a	a	5	test.t0.a	4	Using index
 drop table t0, t1;
+# ###################################################################
+# ## EXPLAIN UPDATE tests
+# ###################################################################
+create table t0 (a int) engine=myisam;
+insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
+explain update t0 set a=3 where a=4;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	8	Using where
+create table t1 (a int, b int, filler char(100), key(a), key(b));
+insert into t1 
+select A.a+10*B.a + 10*C.a, A.a+10*B.a + 10*C.a, 'filler' 
+from t0 A, t0 B, t0 C;
+explain update t1 set a=a+1 where 3>4;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible where
+explain update t1 set a=a+1 where a=3 and a=4;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible where
+# This should use an index,  possible_keys=NULL because there is no WHERE
+explain update t1 set a=a+1 order by a limit 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	512	
+# This should use range, possible_keys={a,b}
+explain update t1 set filler='fooo' where a<20 and b < 10;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	a,b	a	5	NULL	1	Using where
+# This should use ALL + filesort
+explain update t1 set filler='fooo' order by a+1 limit 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	512	
+# This should use range + using filesort
+explain update t1 set filler='fooo' where a<20 order by b limit 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	range	a	a	5	NULL	1	Using where
+# Try some subqueries:
+explain update t1 set filler='fooo' where a < (select max(a) from t0);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	range	a	a	5	NULL	1	Using where
+2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	8	
+explain update t1 set filler='fooo' where a < (select max(a) from t0 where a < t1.b);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	512	Using where
+2	DEPENDENT SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	8	Using where
+#
+#  Tests for multi-table UPDATE
+# 
+explain update t0, t1 set t1.a=t1.a+1 where t0.a = t1.a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	8	Using where
+1	SIMPLE	t1	ref	a	a	5	test.t0.a	4	Using index
+drop table t0, t1;