Implementation of MDEV-28 LIMIT ROWS EXAMINED

https://mariadb.atlassian.net/browse/MDEV-28
  
This task implements a new clause LIMIT ROWS EXAMINED <num>
as an extention to the ANSI LIMIT clause. This extension
allows to limit the number of rows and/or keys a query
would access (read and/or write) during query execution.

mysql-test/r/limit_rows_examined.result

+set @save_join_cache_level = @@join_cache_level;
+create table t1 (c1 char(2));
+create table t2 (c2 char(2));
+insert into t1 values ('bb'), ('cc'), ('aa'), ('dd');
+insert into t2 values ('bb'), ('cc'), ('dd'), ('ff');
+create table t1i (c1 char(2) key);
+create table t2i (c2 char(2) key);
+insert into t1i values ('bb'), ('cc'), ('aa'), ('dd');
+insert into t2i values ('bb'), ('cc'), ('dd'), ('ff');
+=========================================================================
+Simple joins
+=========================================================================
+Simple nested loops join without blocking
+set @@join_cache_level=0;
+explain
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 2;
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 3 rows, which exceeds LIMIT ROWS EXAMINED (2). The query result may be incomplete.
+explain
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 4;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1i	index	PRIMARY	PRIMARY	2	NULL	4	Using index
+1	SIMPLE	t2i	eq_ref	PRIMARY	PRIMARY	2	test.t1i.c1	1	Using index
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 4;
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 5 rows, which exceeds LIMIT ROWS EXAMINED (4). The query result may be incomplete.
+Blocked nested loops join, empty result set because of blocking
+set @@join_cache_level=1;
+explain
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 6;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	4	Using where; Using join buffer (flat, BNL join)
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 6;
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 7 rows, which exceeds LIMIT ROWS EXAMINED (6). The query result may be incomplete.
+explain
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 6;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1i	index	PRIMARY	PRIMARY	2	NULL	4	Using index
+1	SIMPLE	t2i	index	PRIMARY	PRIMARY	2	NULL	4	Using where; Using index; Using join buffer (flat, BNL join)
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 6;
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 7 rows, which exceeds LIMIT ROWS EXAMINED (6). The query result may be incomplete.
+set @@join_cache_level=6;
+explain
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 3;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+1	SIMPLE	t2	hash_ALL	NULL	#hash#$hj	3	test.t1.c1	4	Using where; Using join buffer (flat, BNLH join)
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 3;
+c1	c2
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 4 rows, which exceeds LIMIT ROWS EXAMINED (3). The query result may be incomplete.
+explain
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 6;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1i	index	PRIMARY	PRIMARY	2	NULL	4	Using index
+1	SIMPLE	t2i	index	PRIMARY	PRIMARY	2	NULL	4	Using where; Using index; Using join buffer (flat, BNL join)
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 6;
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 7 rows, which exceeds LIMIT ROWS EXAMINED (6). The query result may be incomplete.
+Mix LIMIT ROWS EXAMINED with LIMIT
+set @@join_cache_level=0;
+explain
+select * from t1, t2 where c1 < c2 LIMIT 1 ROWS EXAMINED 4;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1, t2 where c1 < c2 LIMIT 1 ROWS EXAMINED 4;
+c1	c2
+bb	cc
+explain
+select * from t1, t2 where c1 < c2 LIMIT 1,1 ROWS EXAMINED 4;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1, t2 where c1 < c2 LIMIT 1,1 ROWS EXAMINED 4;
+c1	c2
+bb	dd
+Empty table optimized away during constant optimization
+create table t0 (c0 int);
+explain
+select * from t0 LIMIT ROWS EXAMINED 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t0	system	NULL	NULL	NULL	NULL	0	const row not found
+explain
+select * from t0 LIMIT ROWS EXAMINED 1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t0	system	NULL	NULL	NULL	NULL	0	const row not found
+select * from t0 LIMIT ROWS EXAMINED 1;
+c0
+drop table t0;
+create table t0 (c0 char(2) primary key);
+insert into t0 values  ('bb'), ('cc'), ('aa');
+explain
+select * from t0 where c0 = 'bb' LIMIT ROWS EXAMINED 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t0	const	PRIMARY	PRIMARY	2	const	1	Using index
+select * from t0 where c0 = 'bb' LIMIT ROWS EXAMINED 0;
+c0
+bb
+explain
+select * from t0, t1 where c0 = 'bb' and c1 > c0 LIMIT ROWS EXAMINED 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t0	const	PRIMARY	PRIMARY	2	const	1	Using index
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t0, t1 where c0 = 'bb' and c1 > c0 LIMIT ROWS EXAMINED 0;
+c0	c1
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 2 rows, which exceeds LIMIT ROWS EXAMINED (0). The query result may be incomplete.
+set @@join_cache_level = @save_join_cache_level;
+drop table t0;
+=========================================================================
+LIMIT ROWS EXAMINED with parameter argument
+=========================================================================
+set @@join_cache_level=0;
+set @l = 2;
+Prepared statement parameter
+prepare st1 from "select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED ?";
+execute st1 using @l;
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 3 rows, which exceeds LIMIT ROWS EXAMINED (2). The query result may be incomplete.
+deallocate prepare st1;
+User variable (not supported for LIMIT in MariaDB 5.3/MySQL 5.1)
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED @l;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '@l' at line 1
+Stored procedure parameter (not supported for LIMIT in MariaDB 5.3/MySQL 5.1)
+CREATE PROCEDURE test_limit_rows(l int)
+BEGIN
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED l;
+END|
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'l;
+END' at line 3
+set @@join_cache_level = @save_join_cache_level;
+=========================================================================
+UNIONs (with several LIMIT ROWS EXAMINED clauses)
+=========================================================================
+(select * from t1, t2 where c1 = c2)
+UNION
+(select * from t1, t2 where c1 < c2) LIMIT ROWS EXAMINED 6;
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 8 rows, which exceeds LIMIT ROWS EXAMINED (6). The query result may be incomplete.
+(select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 0)
+UNION
+(select * from t1, t2 where c1 < c2 LIMIT ROWS EXAMINED 6);
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 8 rows, which exceeds LIMIT ROWS EXAMINED (6). The query result may be incomplete.
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 0
+UNION
+select * from t1, t2 where c1 < c2 LIMIT ROWS EXAMINED 6;
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 8 rows, which exceeds LIMIT ROWS EXAMINED (6). The query result may be incomplete.
+(select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 0)
+UNION
+(select * from t1, t2 where c1 < c2 LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 6;
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 8 rows, which exceeds LIMIT ROWS EXAMINED (6). The query result may be incomplete.
+(select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 0)
+UNION
+(select * from t1, t2 where c1 < c2 LIMIT ROWS EXAMINED 0)
+LIMIT 1 ROWS EXAMINED 6;
+c1	c2
+bb	bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 8 rows, which exceeds LIMIT ROWS EXAMINED (6). The query result may be incomplete.
+(select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 0)
+UNION
+(select * from t1, t2 where c1 < c2 LIMIT ROWS EXAMINED 0)
+LIMIT 2 ROWS EXAMINED 10;
+c1	c2
+bb	bb
+cc	cc
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 12 rows, which exceeds LIMIT ROWS EXAMINED (10). The query result may be incomplete.
+=========================================================================
+Subqueries (with several LIMIT ROWS EXAMINED clauses)
+=========================================================================
+Subqueries, semi-join
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 11);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	2	func	1	
+2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 11);
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 12 rows, which exceeds LIMIT ROWS EXAMINED (11). The query result may be incomplete.
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ')
+LIMIT ROWS EXAMINED 11;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	2	func	1	
+2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ')
+LIMIT ROWS EXAMINED 11;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 12 rows, which exceeds LIMIT ROWS EXAMINED (11). The query result may be incomplete.
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 11;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	2	func	1	
+2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 11;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 12 rows, which exceeds LIMIT ROWS EXAMINED (11). The query result may be incomplete.
+explain
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ')
+LIMIT ROWS EXAMINED 6;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1i	index	PRIMARY	PRIMARY	2	NULL	4	Using where; Using index
+1	PRIMARY	t2i	index	PRIMARY	PRIMARY	2	NULL	4	Using where; Using index; Using join buffer (flat, BNL join)
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ')
+LIMIT ROWS EXAMINED 6;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 7 rows, which exceeds LIMIT ROWS EXAMINED (6). The query result may be incomplete.
+Subqueries with IN-TO-EXISTS
+set @@optimizer_switch='semijoin=off,in_to_exists=on,materialization=off';
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 4);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 4);
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 5 rows, which exceeds LIMIT ROWS EXAMINED (4). The query result may be incomplete.
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ')
+LIMIT ROWS EXAMINED 4;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ')
+LIMIT ROWS EXAMINED 4;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 5 rows, which exceeds LIMIT ROWS EXAMINED (4). The query result may be incomplete.
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 4;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 4;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 5 rows, which exceeds LIMIT ROWS EXAMINED (4). The query result may be incomplete.
+explain
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ')
+LIMIT ROWS EXAMINED 9;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1i	index	NULL	PRIMARY	2	NULL	4	Using where; Using index
+2	DEPENDENT SUBQUERY	t2i	unique_subquery	PRIMARY	PRIMARY	2	func	1	Using index; Using where
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ')
+LIMIT ROWS EXAMINED 9;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 10 rows, which exceeds LIMIT ROWS EXAMINED (9). The query result may be incomplete.
+Same as above, without subquery cache
+set @@optimizer_switch='subquery_cache=off';
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 2);
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 3 rows, which exceeds LIMIT ROWS EXAMINED (2). The query result may be incomplete.
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ')
+LIMIT ROWS EXAMINED 2;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 3 rows, which exceeds LIMIT ROWS EXAMINED (2). The query result may be incomplete.
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 2;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 3 rows, which exceeds LIMIT ROWS EXAMINED (2). The query result may be incomplete.
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ')
+LIMIT ROWS EXAMINED 5;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 6 rows, which exceeds LIMIT ROWS EXAMINED (5). The query result may be incomplete.
+Subqueries with materialization
+set @@optimizer_switch='semijoin=off,in_to_exists=off,materialization=on,subquery_cache=on';
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 13);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 13);
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 14 rows, which exceeds LIMIT ROWS EXAMINED (13). The query result may be incomplete.
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ') LIMIT ROWS EXAMINED 13;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ') LIMIT ROWS EXAMINED 13;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 14 rows, which exceeds LIMIT ROWS EXAMINED (13). The query result may be incomplete.
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 13;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+2	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 13;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 14 rows, which exceeds LIMIT ROWS EXAMINED (13). The query result may be incomplete.
+explain
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ') LIMIT ROWS EXAMINED 17;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1i	index	NULL	PRIMARY	2	NULL	4	Using where; Using index
+2	MATERIALIZED	t2i	index	PRIMARY	PRIMARY	2	NULL	4	Using where; Using index
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ') LIMIT ROWS EXAMINED 17;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 18 rows, which exceeds LIMIT ROWS EXAMINED (17). The query result may be incomplete.
+set @@optimizer_switch='default';
+=========================================================================
+Views and derived tables
+=========================================================================
+create view v1 as
+select * from t1 where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 13);
+ERROR 42000: This version of MySQL doesn't yet support 'LIMIT ROWS EXAMINED inside views'
+create view v1 as
+select * from t1 where c1 IN (select * from t2 where c2 > ' ');
+select * from v1;
+c1
+bb
+cc
+dd
+select * from v1 LIMIT ROWS EXAMINED 17;
+c1
+bb
+cc
+dd
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 18 rows, which exceeds LIMIT ROWS EXAMINED (17). The query result may be incomplete.
+select * from v1 LIMIT ROWS EXAMINED 16;
+c1
+bb
+cc
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 18 rows, which exceeds LIMIT ROWS EXAMINED (16). The query result may be incomplete.
+select * from v1 LIMIT ROWS EXAMINED 11;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 12 rows, which exceeds LIMIT ROWS EXAMINED (11). The query result may be incomplete.
+drop view v1;
+explain
+select *
+from (select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)) as tmp
+LIMIT ROWS EXAMINED 11;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+3	MATERIALIZED	t2	ALL	NULL	NULL	NULL	NULL	4	Using where
+select *
+from (select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)) as tmp
+LIMIT ROWS EXAMINED 11;
+c1
+bb
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 12 rows, which exceeds LIMIT ROWS EXAMINED (11). The query result may be incomplete.
+=========================================================================
+Aggregation
+=========================================================================
+create table t3 (c1 char(2), c2 int);
+insert into t3 values
+('aa', 1), ('aa', 2),
+('bb', 3), ('bb', 4), ('bb', 5);
+explain
+select c1, sum(c2) from t3 group by c1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	5	Using temporary; Using filesort
+select c1, sum(c2) from t3 group by c1;
+c1	sum(c2)
+aa	3
+bb	12
+explain
+select c1, sum(c2) from t3 group by c1 LIMIT ROWS EXAMINED 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	5	Using temporary; Using filesort
+select c1, sum(c2) from t3 group by c1 LIMIT ROWS EXAMINED 0;
+c1	sum(c2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 2 rows, which exceeds LIMIT ROWS EXAMINED (0). The query result may be incomplete.
+select c1, sum(c2) from t3 group by c1 LIMIT ROWS EXAMINED 1;
+ERROR HY000: Sort aborted
+select c1, sum(c2) from t3 group by c1 LIMIT ROWS EXAMINED 20;
+c1	sum(c2)
+aa	3
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 21 rows, which exceeds LIMIT ROWS EXAMINED (20). The query result may be incomplete.
+select c1, sum(c2) from t3 group by c1 LIMIT ROWS EXAMINED 21;
+c1	sum(c2)
+aa	3
+bb	12
+create table t3i (c1 char(2), c2 int);
+create index it3i on t3i(c1);
+create index it3j on t3i(c2,c1);
+insert into t3i values
+('aa', 1), ('aa', 2),
+('bb', 3), ('bb', 4), ('bb', 5);
+explain
+select c1, sum(c2) from t3i group by c1 LIMIT ROWS EXAMINED 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3i	index	NULL	it3j	8	NULL	5	Using index; Using temporary; Using filesort
+select c1, sum(c2) from t3i group by c1 LIMIT ROWS EXAMINED 0;
+c1	sum(c2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 2 rows, which exceeds LIMIT ROWS EXAMINED (0). The query result may be incomplete.
+select c1, sum(c2) from t3i group by c1 LIMIT ROWS EXAMINED 1;
+ERROR HY000: Sort aborted
+select c1, sum(c2) from t3i group by c1 LIMIT ROWS EXAMINED 20;
+c1	sum(c2)
+aa	3
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 21 rows, which exceeds LIMIT ROWS EXAMINED (20). The query result may be incomplete.
+select c1, sum(c2) from t3i group by c1 LIMIT ROWS EXAMINED 21;
+c1	sum(c2)
+aa	3
+bb	12
+Aggregation without grouping
+explain
+select min(c2) from t3 LIMIT ROWS EXAMINED 5;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	5	
+select min(c2) from t3 LIMIT ROWS EXAMINED 5;
+min(c2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 6 rows, which exceeds LIMIT ROWS EXAMINED (5). The query result may be incomplete.
+select max(c2) from t3 LIMIT ROWS EXAMINED 6;
+max(c2)
+5
+select max(c2) from t3 LIMIT ROWS EXAMINED 0;
+max(c2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 1 rows, which exceeds LIMIT ROWS EXAMINED (0). The query result may be incomplete.
+explain
+select max(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 5;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	5	Using where
+select max(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 5;
+max(c2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 6 rows, which exceeds LIMIT ROWS EXAMINED (5). The query result may be incomplete.
+select max(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 6;
+max(c2)
+NULL
+select max(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 0;
+max(c2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 1 rows, which exceeds LIMIT ROWS EXAMINED (0). The query result may be incomplete.
+explain
+select count(c2) from t3 LIMIT ROWS EXAMINED 5;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	5	
+select count(c2) from t3 LIMIT ROWS EXAMINED 5;
+count(c2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 6 rows, which exceeds LIMIT ROWS EXAMINED (5). The query result may be incomplete.
+select count(c2) from t3 LIMIT ROWS EXAMINED 6;
+count(c2)
+5
+select count(c2) from t3 LIMIT ROWS EXAMINED 0;
+count(c2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 1 rows, which exceeds LIMIT ROWS EXAMINED (0). The query result may be incomplete.
+explain
+select count(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 5;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	5	Using where
+select count(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 5;
+count(c2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 6 rows, which exceeds LIMIT ROWS EXAMINED (5). The query result may be incomplete.
+select count(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 6;
+count(c2)
+0
+explain
+select sum(c2) from t3 LIMIT ROWS EXAMINED 5;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	5	
+select sum(c2) from t3 LIMIT ROWS EXAMINED 5;
+sum(c2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 6 rows, which exceeds LIMIT ROWS EXAMINED (5). The query result may be incomplete.
+select sum(c2) from t3 LIMIT ROWS EXAMINED 6;
+sum(c2)
+15
+The query result is found during optimization, LIMIT ROWS EXAMINED has no effect.
+explain
+select max(c1) from t3i LIMIT ROWS EXAMINED 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+select max(c1) from t3i LIMIT ROWS EXAMINED 0;
+max(c1)
+bb
+create table t3_empty like t3;
+explain
+select max(c1) from t3_empty LIMIT ROWS EXAMINED 0;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3_empty	system	NULL	NULL	NULL	NULL	0	const row not found
+select max(c1) from t3_empty LIMIT ROWS EXAMINED 0;
+max(c1)
+NULL
+drop table t3_empty;
+=========================================================================
+Sorting
+=========================================================================
+explain
+select c1, c2 from t3 order by c2, c1 LIMIT ROWS EXAMINED 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3	ALL	NULL	NULL	NULL	NULL	5	Using filesort
+select c1, c2 from t3 order by c2, c1 LIMIT ROWS EXAMINED 2;
+ERROR HY000: Sort aborted
+explain
+select c1, c2 from t3i order by c2, c1 LIMIT ROWS EXAMINED 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3i	index	NULL	it3j	8	NULL	5	Using index
+select c1, c2 from t3i order by c2, c1 LIMIT ROWS EXAMINED 2;
+c1	c2
+aa	1
+aa	2
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 3 rows, which exceeds LIMIT ROWS EXAMINED (2). The query result may be incomplete.
+explain
+select c1, c2 from t3i order by c2, c1 desc LIMIT ROWS EXAMINED 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t3i	index	NULL	it3j	8	NULL	5	Using index; Using filesort
+select c1, c2 from t3i order by c2, c1 desc LIMIT ROWS EXAMINED 2;
+ERROR HY000: Sort aborted
+drop table t3,t3i;
+=========================================================================
+INSERT/DELETE/UPDATE
+=========================================================================
+INSERT ... SELECT
+CREATE TABLE t4 (a int);
+INSERT INTO t4 values (1), (2);
+INSERT INTO t4 SELECT a + 2 FROM t4 LIMIT ROWS EXAMINED 0;
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 2 rows, which exceeds LIMIT ROWS EXAMINED (0). The query result may be incomplete.
+select * from t4;
+a
+1
+2
+INSERT INTO t4 SELECT a + 2 FROM t4 LIMIT ROWS EXAMINED 6;
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 8 rows, which exceeds LIMIT ROWS EXAMINED (6). The query result may be incomplete.
+select * from t4;
+a
+1
+2
+3
+drop table t4;
+DELETE - LIMIT ROWS EXAMINED not supported
+CREATE TABLE t4 (a int);
+INSERT INTO t4 values (1), (2);
+DELETE FROM t4 WHERE t4.a > 0 LIMIT ROWS EXAMINED 0;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'EXAMINED 0' at line 1
+DELETE FROM t4 WHERE t4.a > 0 LIMIT 0 ROWS EXAMINED 0;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'EXAMINED 0' at line 1
+drop table t4;
+UPDATE - LIMIT ROWS EXAMINED not supported
+CREATE TABLE t4 (a int);
+INSERT INTO t4 values (1), (2);
+update t4 set a=a+10 LIMIT ROWS EXAMINED 0;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'EXAMINED 0' at line 1
+update t4 set a=a+10 LIMIT 0 ROWS EXAMINED 0;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'EXAMINED 0' at line 1
+drop table t4;
+drop table t1,t2,t1i,t2i;
+=========================================================================
+Test cases for bugs
+=========================================================================
+
+MDEV-115
+
+SET @@optimizer_switch='in_to_exists=on,outer_join_with_cache=on';
+CREATE TABLE t1 ( a VARCHAR(3) ) ENGINE=MyISAM;
+INSERT INTO t1 VALUES ('USA');
+CREATE TABLE t2 ( b INT );
+INSERT INTO t2 VALUES (3899),(3914),(3888);
+CREATE TABLE t3 ( c VARCHAR(33), d INT );
+INSERT INTO t3 VALUES ('USASpanish',8),('USATagalog',0),('USAVietnamese',0);
+EXPLAIN
+SELECT DISTINCT a AS field1 FROM t1, t2 
+WHERE EXISTS (SELECT c FROM t3 LEFT JOIN t2 ON b = d) 
+HAVING field1 > 8 LIMIT ROWS EXAMINED 20;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	Using temporary
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	Distinct
+2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
+SELECT DISTINCT a AS field1 FROM t1, t2 
+WHERE EXISTS (SELECT c FROM t3 LEFT JOIN t2 ON b = d) 
+HAVING field1 > 8 LIMIT ROWS EXAMINED 20;
+field1
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 24 rows, which exceeds LIMIT ROWS EXAMINED (20). The query result may be incomplete.
+EXPLAIN
+SELECT DISTINCT a FROM t1, t2  HAVING a > ' ' LIMIT ROWS EXAMINED 14;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	system	NULL	NULL	NULL	NULL	1	Using temporary
+1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Distinct
+SELECT DISTINCT a FROM t1, t2  HAVING a > ' ' LIMIT ROWS EXAMINED 14;
+a
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 15 rows, which exceeds LIMIT ROWS EXAMINED (14). The query result may be incomplete.
+SELECT DISTINCT a FROM t1, t2  HAVING a > ' ' LIMIT ROWS EXAMINED 15;
+a
+USA
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 16 rows, which exceeds LIMIT ROWS EXAMINED (15). The query result may be incomplete.
+SELECT DISTINCT a FROM t1, t2  HAVING a > ' ' LIMIT ROWS EXAMINED 16;
+a
+USA
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 17 rows, which exceeds LIMIT ROWS EXAMINED (16). The query result may be incomplete.
+drop table t1,t2,t3;
+set @@optimizer_switch='default';
+
+MDEV-153
+
+CREATE TABLE t1 ( a TIME, b DATETIME, KEY(a), KEY(b) ) ENGINE=MyISAM;
+INSERT INTO t1 VALUES 
+('21:22:34.025509', '2002-02-13 17:30:06.013935'), 
+('10:50:38.059966', '2008-09-27 00:34:58.026613'), 
+('00:21:38.058143', '2007-05-28 00:00:00');
+CREATE TABLE t2 ( c INT, d TIME, e DATETIME, f VARCHAR(1), KEY(c) ) ENGINE=MyISAM;
+INSERT INTO t2 VALUES
+(0, '11:03:22.062907', '2007-06-02 11:16:01.053212', 'a'), 
+(0, '08:14:05.001407', '1900-01-01 00:00:00', 'm'), 
+(5, '19:03:16.024974', '1900-01-01 00:00:00', 'f'), 
+(1, '07:23:34.034234', '2000-11-26 05:01:11.054228', 'z'), 
+(6, '12:29:32.019411', '2006-02-13 00:00:00', 'f'), 
+(6, '06:07:10.010496', '2007-06-08 04:35:26.020373', 'a'), 
+(7, '22:55:09.020772', '2005-04-27 00:00:00', 'i');
+EXPLAIN
+SELECT a AS field1, alias2.d AS field2, alias2.f AS field3, alias2.e AS field4, b AS field5
+FROM t1, t2 AS alias2, t2 AS alias3 
+WHERE alias3.c IN ( SELECT 1 UNION SELECT 6 ) 
+GROUP BY field1, field2, field3, field4, field5
+LIMIT ROWS EXAMINED 120;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using temporary; Using filesort
+1	PRIMARY	alias2	ALL	NULL	NULL	NULL	NULL	7	Using join buffer (flat, BNL join)
+1	PRIMARY	alias3	index	NULL	c	5	NULL	7	Using where; Using index; Using join buffer (incremental, BNL join)
+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	
+FLUSH STATUS;
+SELECT a AS field1, alias2.d AS field2, alias2.f AS field3, alias2.e AS field4, b AS field5
+FROM t1, t2 AS alias2, t2 AS alias3 
+WHERE alias3.c IN ( SELECT 1 UNION SELECT 6 ) 
+GROUP BY field1, field2, field3, field4, field5
+LIMIT ROWS EXAMINED 120;
+ERROR HY000: Sort aborted
+SHOW STATUS LIKE 'Handler_read%';
+Variable_name	Value
+Handler_read_first	0
+Handler_read_key	4
+Handler_read_next	0
+Handler_read_prev	0
+Handler_read_rnd	0
+Handler_read_rnd_deleted	0
+Handler_read_rnd_next	52
+SHOW STATUS LIKE 'Handler_tmp%';
+Variable_name	Value
+Handler_tmp_update	0
+Handler_tmp_write	66
+FLUSH STATUS;
+SELECT a AS field1, alias2.d AS field2, alias2.f AS field3, alias2.e AS field4, b AS field5
+FROM t1, t2 AS alias2, t2 AS alias3 
+WHERE alias3.c IN ( SELECT 1 UNION SELECT 6 ) 
+GROUP BY field1, field2, field3, field4, field5
+LIMIT ROWS EXAMINED 250;
+field1	field2	field3	field4	field5
+00:21:38	06:07:10	a	2007-06-08 04:35:26	2007-05-28 00:00:00
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 251 rows, which exceeds LIMIT ROWS EXAMINED (250). The query result may be incomplete.
+SHOW STATUS LIKE 'Handler_read%';
+Variable_name	Value
+Handler_read_first	0
+Handler_read_key	5
+Handler_read_next	0
+Handler_read_prev	0
+Handler_read_rnd	2
+Handler_read_rnd_deleted	1
+Handler_read_rnd_next	110
+SHOW STATUS LIKE 'Handler_tmp%';
+Variable_name	Value
+Handler_tmp_update	0
+Handler_tmp_write	133
+drop table t1, t2;
+
+MDEV-161 LIMIT_ROWS EXAMINED: query with the limit and NOT EXISTS, without GROUP BY or aggregate,
+returns rows, while the same query without the limit returns empty set
+
+CREATE TABLE t1 ( a INT, b INT );
+INSERT INTO t1 VALUES (3911,17),(3847,33),(3857,26);
+CREATE TABLE t2 ( c VARCHAR(16) );
+INSERT INTO t2 VALUES ('English'),('French'),('German');
+CREATE TABLE t3 ( d INT, e VARCHAR(32) );
+INSERT INTO t3 VALUES (3813,'United States'),(3814,'United States');
+SELECT * FROM t1 AS alias1, t2 AS alias2 
+WHERE NOT EXISTS (
+SELECT * FROM t1 LEFT OUTER JOIN t3 
+ON (d = a) 
+WHERE b <= alias1.b OR e != alias2.c  
+);
+a	b	c
+SELECT * FROM t1 AS alias1, t2 AS alias2 
+WHERE NOT EXISTS ( 
+SELECT * FROM t1 LEFT OUTER JOIN t3 
+ON (d = a) 
+WHERE b <= alias1.b OR e != alias2.c  
+) LIMIT ROWS EXAMINED 20;
+a	b	c
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 25 rows, which exceeds LIMIT ROWS EXAMINED (20). The query result may be incomplete.
+drop table t1, t2, t3;
+
+MDEV-174: LIMIT ROWS EXAMINED: Assertion `0' failed in net_end_statement(THD*)
+with subquery in SELECT, constant table, aggregate function
+
+CREATE TABLE t1 ( a INT );
+CREATE TABLE t2 ( b INT, c INT, KEY(c) );
+INSERT INTO t2 VALUES 
+(5, 0),(3, 4),(6, 1),
+(5, 8),(4, 9),(8, 1);
+SELECT (SELECT MAX(c) FROM t1, t2)
+FROM t2
+WHERE c = (SELECT MAX(b) FROM t2)
+LIMIT ROWS EXAMINED 3;
+(SELECT MAX(c) FROM t1, t2)
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 10 rows, which exceeds LIMIT ROWS EXAMINED (3). The query result may be incomplete.
+drop table t1, t2;
+
+MDEV-178: LIMIT ROWS EXAMINED: Assertion `0' failed in net_end_statement(THD*) on the
+2nd PS execution, with DISTINCT, FROM subquery or view in SELECT, JOIN in nested subquery
+
+CREATE TABLE t1 ( a INT );
+INSERT INTO t1 VALUES (2),(3),(150);
+CREATE TABLE t2 ( b INT );
+INSERT INTO t2 VALUES (2),(17),(3),(6);
+CREATE VIEW v AS
+SELECT DISTINCT * FROM t1 WHERE a > (SELECT COUNT(*) FROM t1, t2 WHERE a = b);
+PREPARE ps FROM 'SELECT * FROM v LIMIT ROWS EXAMINED 21';
+EXECUTE ps;
+a
+3
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 22 rows, which exceeds LIMIT ROWS EXAMINED (21). The query result may be incomplete.
+EXECUTE ps;
+a
+3
+Warnings:
+Warning	1930	Query execution was interrupted. The query examined at least 22 rows, which exceeds LIMIT ROWS EXAMINED (21). The query result may be incomplete.
+drop view v;
+drop table t1, t2;

mysql-test/suite/rpl/r/rpl_stop_slave.result

@@ -14,7 +14,7 @@ include/stop_slave.inc
 # Suspend the INSERT statement in current transaction on SQL thread.
 # It guarantees that SQL thread is applying the transaction when
 # STOP SLAVE command launchs.
-SET GLOBAL debug= 'd,after_mysql_insert';
+SET GLOBAL debug= '+d,after_mysql_insert,*';
 include/start_slave.inc
 
 # CREATE TEMPORARY TABLE with InnoDB engine
@@ -131,7 +131,6 @@ include/diff_tables.inc [master:t1, slave:t1]
 START SLAVE SQL_THREAD;
 include/wait_for_slave_sql_to_start.inc
 # Test end
-SET GLOBAL debug= '$debug_save';
 include/restart_slave.inc
 [connection master]
 DROP TABLE t1, t2;
@@ -151,7 +150,7 @@ CREATE TABLE t1 (c1 INT KEY, c2 INT) ENGINE=InnoDB;
 CREATE TABLE t2 (c1 INT) ENGINE=MyISAM;
 INSERT INTO t1 VALUES(1, 1);
 [connection master]
-SET GLOBAL debug= 'd,dump_thread_wait_before_send_xid';
+SET GLOBAL debug= '+d,dump_thread_wait_before_send_xid,*';
 [connection slave]
 include/restart_slave.inc
 BEGIN;
@@ -176,5 +175,4 @@ include/wait_for_slave_to_stop.inc
 include/start_slave.inc
 [connection master]
 DROP TABLE t1, t2;
-SET GLOBAL debug= $debug_save;
 include/rpl_end.inc

mysql-test/suite/rpl/t/rpl_stop_slave.test

@@ -23,7 +23,7 @@ source include/stop_slave.inc;
 --echo # It guarantees that SQL thread is applying the transaction when
 --echo # STOP SLAVE command launchs.
 let $debug_save= `SELECT @@GLOBAL.debug`;
-SET GLOBAL debug= 'd,after_mysql_insert';
+SET GLOBAL debug= '+d,after_mysql_insert,*';
 source include/start_slave.inc;
 
 --echo
@@ -53,7 +53,9 @@ let $tmp_table_stm= CREATE TEMPORARY TABLE tt1(c1 INT) ENGINE = MyISAM
 source extra/rpl_tests/rpl_stop_slave.test;
 
 --echo # Test end
-SET GLOBAL debug= '$debug_save';
+--disable_query_log
+eval SET GLOBAL debug= '$debug_save';
+--enable_query_log
 source include/restart_slave_sql.inc;
 
 --source include/rpl_connection_master.inc
@@ -81,7 +83,7 @@ sync_slave_with_master;
 --source include/rpl_connection_master.inc
 
 let $debug_save= `SELECT @@GLOBAL.debug`;
-SET GLOBAL debug= 'd,dump_thread_wait_before_send_xid';
+SET GLOBAL debug= '+d,dump_thread_wait_before_send_xid,*';
 
 --source include/rpl_connection_slave.inc
 source include/restart_slave_sql.inc;
@@ -121,5 +123,7 @@ source include/start_slave.inc;
 
 --source include/rpl_connection_master.inc
 DROP TABLE t1, t2;
-SET GLOBAL debug= $debug_save;
+--disable_query_log
+eval SET GLOBAL debug= '$debug_save';
+--enable_query_log
 --source include/rpl_end.inc

mysql-test/t/limit_rows_examined.test

+#
+# Tests for LIMIT ROWS EXAMINED, MDEV-28
+#
+
+set @save_join_cache_level = @@join_cache_level;
+
+create table t1 (c1 char(2));
+create table t2 (c2 char(2));
+
+insert into t1 values ('bb'), ('cc'), ('aa'), ('dd');
+insert into t2 values ('bb'), ('cc'), ('dd'), ('ff');
+
+create table t1i (c1 char(2) key);
+create table t2i (c2 char(2) key);
+
+insert into t1i values ('bb'), ('cc'), ('aa'), ('dd');
+insert into t2i values ('bb'), ('cc'), ('dd'), ('ff');
+
+--echo =========================================================================
+--echo Simple joins
+--echo =========================================================================
+
+--echo Simple nested loops join without blocking
+set @@join_cache_level=0;
+explain
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 2;
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 2;
+
+explain
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 4;
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 4;
+
+--echo Blocked nested loops join, empty result set because of blocking
+set @@join_cache_level=1;
+explain
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 6;
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 6;
+
+explain
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 6;
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 6;
+
+set @@join_cache_level=6;
+explain
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 3;
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 3;
+
+explain
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 6;
+select * from t1i, t2i where c1 = c2 LIMIT ROWS EXAMINED 6;
+
+--echo Mix LIMIT ROWS EXAMINED with LIMIT
+set @@join_cache_level=0;
+explain
+select * from t1, t2 where c1 < c2 LIMIT 1 ROWS EXAMINED 4;
+select * from t1, t2 where c1 < c2 LIMIT 1 ROWS EXAMINED 4;
+
+explain
+select * from t1, t2 where c1 < c2 LIMIT 1,1 ROWS EXAMINED 4;
+select * from t1, t2 where c1 < c2 LIMIT 1,1 ROWS EXAMINED 4;
+
+--echo Empty table optimized away during constant optimization
+create table t0 (c0 int);
+explain
+select * from t0 LIMIT ROWS EXAMINED 0;
+explain
+select * from t0 LIMIT ROWS EXAMINED 1;
+select * from t0 LIMIT ROWS EXAMINED 1;
+drop table t0;
+
+create table t0 (c0 char(2) primary key);
+insert into t0 values  ('bb'), ('cc'), ('aa');
+
+explain
+select * from t0 where c0 = 'bb' LIMIT ROWS EXAMINED 0;
+select * from t0 where c0 = 'bb' LIMIT ROWS EXAMINED 0;
+
+explain
+select * from t0, t1 where c0 = 'bb' and c1 > c0 LIMIT ROWS EXAMINED 0;
+select * from t0, t1 where c0 = 'bb' and c1 > c0 LIMIT ROWS EXAMINED 0;
+
+set @@join_cache_level = @save_join_cache_level;
+drop table t0;
+
+--echo =========================================================================
+--echo LIMIT ROWS EXAMINED with parameter argument
+--echo =========================================================================
+
+set @@join_cache_level=0;
+set @l = 2;
+
+--echo Prepared statement parameter
+
+prepare st1 from "select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED ?";
+execute st1 using @l;
+deallocate prepare st1;
+
+--echo User variable (not supported for LIMIT in MariaDB 5.3/MySQL 5.1)
+--error 1064
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED @l;
+
+--echo Stored procedure parameter (not supported for LIMIT in MariaDB 5.3/MySQL 5.1)
+
+DELIMITER |;
+--error 1064
+CREATE PROCEDURE test_limit_rows(l int)
+BEGIN
+  select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED l;
+END|
+
+DELIMITER ;|
+
+set @@join_cache_level = @save_join_cache_level;
+
+--echo =========================================================================
+--echo UNIONs (with several LIMIT ROWS EXAMINED clauses)
+--echo =========================================================================
+(select * from t1, t2 where c1 = c2)
+UNION
+(select * from t1, t2 where c1 < c2) LIMIT ROWS EXAMINED 6;
+
+(select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 0)
+UNION
+(select * from t1, t2 where c1 < c2 LIMIT ROWS EXAMINED 6);
+
+select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 0
+UNION
+select * from t1, t2 where c1 < c2 LIMIT ROWS EXAMINED 6;
+
+(select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 0)
+UNION
+(select * from t1, t2 where c1 < c2 LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 6;
+
+(select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 0)
+UNION
+(select * from t1, t2 where c1 < c2 LIMIT ROWS EXAMINED 0)
+LIMIT 1 ROWS EXAMINED 6;
+
+(select * from t1, t2 where c1 = c2 LIMIT ROWS EXAMINED 0)
+UNION
+(select * from t1, t2 where c1 < c2 LIMIT ROWS EXAMINED 0)
+LIMIT 2 ROWS EXAMINED 10;
+
+
+--echo =========================================================================
+--echo Subqueries (with several LIMIT ROWS EXAMINED clauses)
+--echo =========================================================================
+
+--echo Subqueries, semi-join
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 11);
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 11);
+
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ')
+LIMIT ROWS EXAMINED 11;
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ')
+LIMIT ROWS EXAMINED 11;
+
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 11;
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 11;
+
+explain
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ')
+LIMIT ROWS EXAMINED 6;
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ')
+LIMIT ROWS EXAMINED 6;
+
+--echo Subqueries with IN-TO-EXISTS
+set @@optimizer_switch='semijoin=off,in_to_exists=on,materialization=off';
+
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 4);
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 4);
+
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ')
+LIMIT ROWS EXAMINED 4;
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ')
+LIMIT ROWS EXAMINED 4;
+
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 4;
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 4;
+
+explain
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ')
+LIMIT ROWS EXAMINED 9;
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ')
+LIMIT ROWS EXAMINED 9;
+
+--echo Same as above, without subquery cache
+set @@optimizer_switch='subquery_cache=off';
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 2);
+
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ')
+LIMIT ROWS EXAMINED 2;
+
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 2;
+
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ')
+LIMIT ROWS EXAMINED 5;
+
+--echo Subqueries with materialization
+set @@optimizer_switch='semijoin=off,in_to_exists=off,materialization=on,subquery_cache=on';
+
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 13);
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 13);
+
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ') LIMIT ROWS EXAMINED 13;
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ') LIMIT ROWS EXAMINED 13;
+
+explain
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 13;
+select * from t1
+where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)
+LIMIT ROWS EXAMINED 13;
+
+explain
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ') LIMIT ROWS EXAMINED 17;
+select * from t1i
+where c1 IN (select * from t2i where c2 > ' ') LIMIT ROWS EXAMINED 17;
+
+set @@optimizer_switch='default';
+
+--echo =========================================================================
+--echo Views and derived tables
+--echo =========================================================================
+
+--error 1235
+create view v1 as
+select * from t1 where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 13);
+
+create view v1 as
+select * from t1 where c1 IN (select * from t2 where c2 > ' ');
+
+select * from v1;
+select * from v1 LIMIT ROWS EXAMINED 17;
+select * from v1 LIMIT ROWS EXAMINED 16;
+select * from v1 LIMIT ROWS EXAMINED 11;
+
+drop view v1;
+
+explain
+select *
+from (select * from t1
+      where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)) as tmp
+LIMIT ROWS EXAMINED 11;
+select *
+from (select * from t1
+      where c1 IN (select * from t2 where c2 > ' ' LIMIT ROWS EXAMINED 0)) as tmp
+LIMIT ROWS EXAMINED 11;
+
+--echo =========================================================================
+--echo Aggregation
+--echo =========================================================================
+create table t3 (c1 char(2), c2 int);
+
+insert into t3 values
+('aa', 1), ('aa', 2),
+('bb', 3), ('bb', 4), ('bb', 5);
+
+explain
+select c1, sum(c2) from t3 group by c1;
+select c1, sum(c2) from t3 group by c1;
+
+explain
+select c1, sum(c2) from t3 group by c1 LIMIT ROWS EXAMINED 0;
+select c1, sum(c2) from t3 group by c1 LIMIT ROWS EXAMINED 0;
+--error 1028
+select c1, sum(c2) from t3 group by c1 LIMIT ROWS EXAMINED 1;
+select c1, sum(c2) from t3 group by c1 LIMIT ROWS EXAMINED 20;
+select c1, sum(c2) from t3 group by c1 LIMIT ROWS EXAMINED 21;
+
+create table t3i (c1 char(2), c2 int);
+create index it3i on t3i(c1);
+create index it3j on t3i(c2,c1);
+
+insert into t3i values
+('aa', 1), ('aa', 2),
+('bb', 3), ('bb', 4), ('bb', 5);
+
+explain
+select c1, sum(c2) from t3i group by c1 LIMIT ROWS EXAMINED 0;
+select c1, sum(c2) from t3i group by c1 LIMIT ROWS EXAMINED 0;
+--error 1028
+select c1, sum(c2) from t3i group by c1 LIMIT ROWS EXAMINED 1;
+select c1, sum(c2) from t3i group by c1 LIMIT ROWS EXAMINED 20;
+select c1, sum(c2) from t3i group by c1 LIMIT ROWS EXAMINED 21;
+
+--echo Aggregation without grouping
+
+explain
+select min(c2) from t3 LIMIT ROWS EXAMINED 5;
+select min(c2) from t3 LIMIT ROWS EXAMINED 5;
+select max(c2) from t3 LIMIT ROWS EXAMINED 6;
+select max(c2) from t3 LIMIT ROWS EXAMINED 0;
+
+explain
+select max(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 5;
+select max(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 5;
+select max(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 6;
+select max(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 0;
+
+explain
+select count(c2) from t3 LIMIT ROWS EXAMINED 5;
+select count(c2) from t3 LIMIT ROWS EXAMINED 5;
+select count(c2) from t3 LIMIT ROWS EXAMINED 6;
+select count(c2) from t3 LIMIT ROWS EXAMINED 0;
+
+explain
+select count(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 5;
+select count(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 5;
+select count(c2) from t3 where c2 > 10 LIMIT ROWS EXAMINED 6;
+
+explain
+select sum(c2) from t3 LIMIT ROWS EXAMINED 5;
+select sum(c2) from t3 LIMIT ROWS EXAMINED 5;
+select sum(c2) from t3 LIMIT ROWS EXAMINED 6;
+
+--echo The query result is found during optimization, LIMIT ROWS EXAMINED has no effect.
+explain
+select max(c1) from t3i LIMIT ROWS EXAMINED 0;
+select max(c1) from t3i LIMIT ROWS EXAMINED 0;
+
+create table t3_empty like t3;
+explain
+select max(c1) from t3_empty LIMIT ROWS EXAMINED 0;
+select max(c1) from t3_empty LIMIT ROWS EXAMINED 0;
+drop table t3_empty;
+
+--echo =========================================================================
+--echo Sorting
+--echo =========================================================================
+
+explain
+select c1, c2 from t3 order by c2, c1 LIMIT ROWS EXAMINED 2;
+--error 1028
+select c1, c2 from t3 order by c2, c1 LIMIT ROWS EXAMINED 2;
+
+explain
+select c1, c2 from t3i order by c2, c1 LIMIT ROWS EXAMINED 2;
+select c1, c2 from t3i order by c2, c1 LIMIT ROWS EXAMINED 2;
+
+explain
+select c1, c2 from t3i order by c2, c1 desc LIMIT ROWS EXAMINED 2;
+--error 1028
+select c1, c2 from t3i order by c2, c1 desc LIMIT ROWS EXAMINED 2;
+
+drop table t3,t3i;
+
+--echo =========================================================================
+--echo INSERT/DELETE/UPDATE
+--echo =========================================================================
+
+--echo INSERT ... SELECT
+CREATE TABLE t4 (a int);
+INSERT INTO t4 values (1), (2);
+INSERT INTO t4 SELECT a + 2 FROM t4 LIMIT ROWS EXAMINED 0;
+select * from t4;
+INSERT INTO t4 SELECT a + 2 FROM t4 LIMIT ROWS EXAMINED 6;
+select * from t4;
+drop table t4;
+
+--echo DELETE - LIMIT ROWS EXAMINED not supported
+CREATE TABLE t4 (a int);
+INSERT INTO t4 values (1), (2);
+--error 1064
+DELETE FROM t4 WHERE t4.a > 0 LIMIT ROWS EXAMINED 0;
+--error 1064
+DELETE FROM t4 WHERE t4.a > 0 LIMIT 0 ROWS EXAMINED 0;
+drop table t4;
+
+--echo UPDATE - LIMIT ROWS EXAMINED not supported
+CREATE TABLE t4 (a int);
+INSERT INTO t4 values (1), (2);
+--error 1064
+update t4 set a=a+10 LIMIT ROWS EXAMINED 0;
+--error 1064
+update t4 set a=a+10 LIMIT 0 ROWS EXAMINED 0;
+drop table t4;
+
+drop table t1,t2,t1i,t2i;
+
+
+--echo =========================================================================
+--echo Test cases for bugs
+--echo =========================================================================
+
+--echo
+--echo MDEV-115
+--echo
+
+SET @@optimizer_switch='in_to_exists=on,outer_join_with_cache=on';
+
+CREATE TABLE t1 ( a VARCHAR(3) ) ENGINE=MyISAM;
+INSERT INTO t1 VALUES ('USA');
+
+CREATE TABLE t2 ( b INT );
+INSERT INTO t2 VALUES (3899),(3914),(3888);
+
+CREATE TABLE t3 ( c VARCHAR(33), d INT );
+INSERT INTO t3 VALUES ('USASpanish',8),('USATagalog',0),('USAVietnamese',0);
+
+EXPLAIN
+SELECT DISTINCT a AS field1 FROM t1, t2 
+WHERE EXISTS (SELECT c FROM t3 LEFT JOIN t2 ON b = d) 
+HAVING field1 > 8 LIMIT ROWS EXAMINED 20;
+
+SELECT DISTINCT a AS field1 FROM t1, t2 
+WHERE EXISTS (SELECT c FROM t3 LEFT JOIN t2 ON b = d) 
+HAVING field1 > 8 LIMIT ROWS EXAMINED 20;
+
+EXPLAIN
+SELECT DISTINCT a FROM t1, t2  HAVING a > ' ' LIMIT ROWS EXAMINED 14;
+SELECT DISTINCT a FROM t1, t2  HAVING a > ' ' LIMIT ROWS EXAMINED 14;
+
+SELECT DISTINCT a FROM t1, t2  HAVING a > ' ' LIMIT ROWS EXAMINED 15;
+SELECT DISTINCT a FROM t1, t2  HAVING a > ' ' LIMIT ROWS EXAMINED 16;
+
+drop table t1,t2,t3;
+
+set @@optimizer_switch='default';
+
+--echo
+--echo MDEV-153
+--echo
+
+CREATE TABLE t1 ( a TIME, b DATETIME, KEY(a), KEY(b) ) ENGINE=MyISAM;
+INSERT INTO t1 VALUES 
+  ('21:22:34.025509', '2002-02-13 17:30:06.013935'), 
+  ('10:50:38.059966', '2008-09-27 00:34:58.026613'), 
+  ('00:21:38.058143', '2007-05-28 00:00:00');
+
+CREATE TABLE t2 ( c INT, d TIME, e DATETIME, f VARCHAR(1), KEY(c) ) ENGINE=MyISAM;
+INSERT INTO t2 VALUES
+  (0, '11:03:22.062907', '2007-06-02 11:16:01.053212', 'a'), 
+  (0, '08:14:05.001407', '1900-01-01 00:00:00', 'm'), 
+  (5, '19:03:16.024974', '1900-01-01 00:00:00', 'f'), 
+  (1, '07:23:34.034234', '2000-11-26 05:01:11.054228', 'z'), 
+  (6, '12:29:32.019411', '2006-02-13 00:00:00', 'f'), 
+  (6, '06:07:10.010496', '2007-06-08 04:35:26.020373', 'a'), 
+  (7, '22:55:09.020772', '2005-04-27 00:00:00', 'i');
+
+EXPLAIN
+SELECT a AS field1, alias2.d AS field2, alias2.f AS field3, alias2.e AS field4, b AS field5
+FROM t1, t2 AS alias2, t2 AS alias3 
+WHERE alias3.c IN ( SELECT 1 UNION SELECT 6 ) 
+GROUP BY field1, field2, field3, field4, field5
+LIMIT ROWS EXAMINED 120;
+
+FLUSH STATUS;
+--error 1028
+SELECT a AS field1, alias2.d AS field2, alias2.f AS field3, alias2.e AS field4, b AS field5
+FROM t1, t2 AS alias2, t2 AS alias3 
+WHERE alias3.c IN ( SELECT 1 UNION SELECT 6 ) 
+GROUP BY field1, field2, field3, field4, field5
+LIMIT ROWS EXAMINED 120;
+SHOW STATUS LIKE 'Handler_read%';
+SHOW STATUS LIKE 'Handler_tmp%';
+
+FLUSH STATUS;
+SELECT a AS field1, alias2.d AS field2, alias2.f AS field3, alias2.e AS field4, b AS field5
+FROM t1, t2 AS alias2, t2 AS alias3 
+WHERE alias3.c IN ( SELECT 1 UNION SELECT 6 ) 
+GROUP BY field1, field2, field3, field4, field5
+LIMIT ROWS EXAMINED 250;
+SHOW STATUS LIKE 'Handler_read%';
+SHOW STATUS LIKE 'Handler_tmp%';
+
+drop table t1, t2;
+
+--echo
+--echo MDEV-161 LIMIT_ROWS EXAMINED: query with the limit and NOT EXISTS, without GROUP BY or aggregate,
+--echo returns rows, while the same query without the limit returns empty set
+--echo
+
+CREATE TABLE t1 ( a INT, b INT );
+INSERT INTO t1 VALUES (3911,17),(3847,33),(3857,26);
+
+CREATE TABLE t2 ( c VARCHAR(16) );
+INSERT INTO t2 VALUES ('English'),('French'),('German');
+
+CREATE TABLE t3 ( d INT, e VARCHAR(32) );
+INSERT INTO t3 VALUES (3813,'United States'),(3814,'United States');
+
+SELECT * FROM t1 AS alias1, t2 AS alias2 
+WHERE NOT EXISTS (
+  SELECT * FROM t1 LEFT OUTER JOIN t3 
+    ON (d = a) 
+  WHERE b <= alias1.b OR e != alias2.c  
+);
+
+SELECT * FROM t1 AS alias1, t2 AS alias2 
+WHERE NOT EXISTS ( 
+  SELECT * FROM t1 LEFT OUTER JOIN t3 
+    ON (d = a) 
+  WHERE b <= alias1.b OR e != alias2.c  
+) LIMIT ROWS EXAMINED 20;
+
+drop table t1, t2, t3;
+
+--echo
+--echo MDEV-174: LIMIT ROWS EXAMINED: Assertion `0' failed in net_end_statement(THD*)
+--echo with subquery in SELECT, constant table, aggregate function
+--echo
+
+CREATE TABLE t1 ( a INT );
+CREATE TABLE t2 ( b INT, c INT, KEY(c) );
+INSERT INTO t2 VALUES 
+  (5, 0),(3, 4),(6, 1),
+  (5, 8),(4, 9),(8, 1);
+
+SELECT (SELECT MAX(c) FROM t1, t2)
+FROM t2
+WHERE c = (SELECT MAX(b) FROM t2)
+LIMIT ROWS EXAMINED 3;
+
+drop table t1, t2;
+
+--echo
+--echo MDEV-178: LIMIT ROWS EXAMINED: Assertion `0' failed in net_end_statement(THD*) on the
+--echo 2nd PS execution, with DISTINCT, FROM subquery or view in SELECT, JOIN in nested subquery
+--echo
+
+CREATE TABLE t1 ( a INT );
+INSERT INTO t1 VALUES (2),(3),(150);
+CREATE TABLE t2 ( b INT );
+INSERT INTO t2 VALUES (2),(17),(3),(6);
+
+CREATE VIEW v AS
+SELECT DISTINCT * FROM t1 WHERE a > (SELECT COUNT(*) FROM t1, t2 WHERE a = b);
+
+PREPARE ps FROM 'SELECT * FROM v LIMIT ROWS EXAMINED 21';
+
+EXECUTE ps;
+EXECUTE ps;
+
+drop view v;
+drop table t1, t2;

sql/lex.h

@@ -204,6 +204,7 @@ static SYMBOL symbols[] = {
   { "EVENT",		SYM(EVENT_SYM)},
   { "EVENTS",		SYM(EVENTS_SYM)},
   { "EVERY",		SYM(EVERY_SYM)},
+  { "EXAMINED",         SYM(EXAMINED_SYM)},
   { "EXECUTE",		SYM(EXECUTE_SYM)},
   { "EXISTS",		SYM(EXISTS)},
   { "EXIT",             SYM(EXIT_SYM)},

sql/share/errmsg.txt

@@ -6296,4 +6296,5 @@ ER_INTERNAL_ERROR
         eng "Internal error: '%-.192s'"
 ER_SPATIAL_MUST_HAVE_GEOM_COL 42000
   eng "A SPATIAL index may only contain a geometrical type column"
-
+ER_QUERY_EXCEEDED_ROWS_EXAMINED_LIMIT
+        eng "Query execution was interrupted. The query examined at least %llu rows, which exceeds LIMIT ROWS EXAMINED (%llu). The query result may be incomplete."

sql/signal_handler.cc

@@ -191,6 +191,10 @@ extern "C" sig_handler handle_fatal_signal(int sig)
     case KILL_SERVER_HARD:
       kreason= "KILL_SERVER";
       break;
+    case ABORT_QUERY:
+    case ABORT_QUERY_HARD:
+      kreason= "ABORT_QUERY";
+      break;
     }
     my_safe_printf_stderr("%s", "\n"
       "Trying to get some variables.\n"

sql/sql_class.cc

@@ -675,6 +675,7 @@ THD::THD()
    first_successful_insert_id_in_cur_stmt(0),
    stmt_depends_on_first_successful_insert_id_in_prev_stmt(FALSE),
    examined_row_count(0),
+   accessed_rows_and_keys(0),
    global_read_lock(0),
    global_disable_checkpoint(0),
    is_fatal_error(0),
@@ -1373,26 +1374,31 @@ void THD::awake(killed_state state_to_set)
 
 int killed_errno(killed_state killed)
 {
+  DBUG_ENTER("killed_errno");
+  DBUG_PRINT("enter", ("killed: %d", killed));
+
   switch (killed) {
   case NOT_KILLED:
   case KILL_HARD_BIT:
-    return 0;                                   // Probably wrong usage
+    DBUG_RETURN(0);                            // Probably wrong usage
   case KILL_BAD_DATA:
   case KILL_BAD_DATA_HARD:
-    return 0;                                   // Not a real error
+  case ABORT_QUERY_HARD:
+  case ABORT_QUERY:
+    DBUG_RETURN(0);                             // Not a real error
   case KILL_CONNECTION:
   case KILL_CONNECTION_HARD:
   case KILL_SYSTEM_THREAD:
   case KILL_SYSTEM_THREAD_HARD:
-    return ER_CONNECTION_KILLED;
+    DBUG_RETURN(ER_CONNECTION_KILLED);
   case KILL_QUERY:
   case KILL_QUERY_HARD:
-    return ER_QUERY_INTERRUPTED;
+    DBUG_RETURN(ER_QUERY_INTERRUPTED);
   case KILL_SERVER:
   case KILL_SERVER_HARD:
-    return ER_SERVER_SHUTDOWN;
+    DBUG_RETURN(ER_SERVER_SHUTDOWN);
   }
-  return 0;                                     // Keep compiler happy
+  DBUG_RETURN(0);                               // Keep compiler happy
 }
 
 
@@ -1975,6 +1981,8 @@ int select_send::send_data(List<Item> &items)
     unit->offset_limit_cnt--;
     return 0;
   }
+  if (thd->killed == ABORT_QUERY)
+    return 0;
 
   /*
     We may be passing the control from mysqld to the client: release the
@@ -2293,6 +2301,8 @@ int select_export::send_data(List<Item> &items)
     unit->offset_limit_cnt--;
     DBUG_RETURN(0);
   }
+  if (thd->killed == ABORT_QUERY)
+    DBUG_RETURN(0);
   row_count++;
   Item *item;
   uint used_length=0,items_left=items.elements;
@@ -2548,6 +2558,9 @@ int select_dump::send_data(List<Item> &items)
     unit->offset_limit_cnt--;
     DBUG_RETURN(0);
   }
+  if (thd->killed == ABORT_QUERY)
+    DBUG_RETURN(0);
+
   if (row_count++ > 1) 
   {
     my_message(ER_TOO_MANY_ROWS, ER(ER_TOO_MANY_ROWS), MYF(0));
@@ -2594,6 +2607,8 @@ int select_singlerow_subselect::send_data(List<Item> &items)
     unit->offset_limit_cnt--;
     DBUG_RETURN(0);
   }
+  if (thd->killed == ABORT_QUERY)
+    DBUG_RETURN(0);
   List_iterator_fast<Item> li(items);
   Item *val_item;
   for (uint i= 0; (val_item= li++); i++)
@@ -2737,6 +2752,8 @@ int select_exists_subselect::send_data(List<Item> &items)
     unit->offset_limit_cnt--;
     DBUG_RETURN(0);
   }
+  if (thd->killed == ABORT_QUERY)
+    DBUG_RETURN(0);
   it->value= 1;
   it->assigned(1);
   DBUG_RETURN(0);

sql/sql_class.h

@@ -365,7 +365,10 @@ public:
 };
 
 
-/* Note: these states are actually bit coded with HARD */
+/**
+  These states are bit coded with HARD. For each state there must be a pair
+  <state_even_num>, and <state_odd_num>_HARD.
+*/
 enum killed_state
 {
   NOT_KILLED= 0,
@@ -374,16 +377,24 @@ enum killed_state
   KILL_BAD_DATA_HARD= 3,
   KILL_QUERY= 4,
   KILL_QUERY_HARD= 5,
+  /*
+    ABORT_QUERY signals to the query processor to stop execution ASAP without
+    issuing an error. Instead a warning is issued, and when possible a partial
+    query result is returned to the client.
+  */
+  ABORT_QUERY= 6,
+  ABORT_QUERY_HARD= 7,
   /*
     All of the following killed states will kill the connection
-    KILL_CONNECTION must be the first of these!
-  */
-  KILL_CONNECTION= 6,
-  KILL_CONNECTION_HARD= 7,
-  KILL_SYSTEM_THREAD= 8,
-  KILL_SYSTEM_THREAD_HARD= 9,
-  KILL_SERVER= 10,
-  KILL_SERVER_HARD= 11
+    KILL_CONNECTION must be the first of these and it must start with
+    an even number (becasue of HARD bit)!
+  */
+  KILL_CONNECTION= 8,
+  KILL_CONNECTION_HARD= 9,
+  KILL_SYSTEM_THREAD= 10,
+  KILL_SYSTEM_THREAD_HARD= 11,
+  KILL_SERVER= 12,
+  KILL_SERVER_HARD= 13
 };
 
 extern int killed_errno(killed_state killed);
@@ -1951,6 +1962,20 @@ public:
     filesort() before reading it for e.g. update.
   */
   ha_rows    examined_row_count;
+  /**
+    The number of rows and/or keys examined by the query, both read,
+    changed or written.
+  */
+  ulonglong accessed_rows_and_keys;
+  /**
+    Check if the number of rows accessed by a statement exceeded
+    LIMIT ROWS EXAMINED. If so, signal the query engine to stop execution.
+  */
+  void check_limit_rows_examined()
+  {
+    if (++accessed_rows_and_keys > lex->limit_rows_examined_cnt)
+      killed= ABORT_QUERY;
+  }
 
   USER_CONN *user_connect;
   CHARSET_INFO *db_charset;
@@ -3643,6 +3668,7 @@ void mark_transaction_to_rollback(THD *thd, bool all);
 inline void handler::increment_statistics(ulong SSV::*offset) const
 {
   status_var_increment(table->in_use->status_var.*offset);
+  table->in_use->check_limit_rows_examined();
 }
 
 inline void handler::decrement_statistics(ulong SSV::*offset) const

sql/sql_insert.cc

@@ -3280,6 +3280,8 @@ int select_insert::send_data(List<Item> &values)
     unit->offset_limit_cnt--;
     DBUG_RETURN(0);
   }
+  if (thd->killed == ABORT_QUERY)
+    DBUG_RETURN(0);
 
   thd->count_cuted_fields= CHECK_FIELD_WARN;	// Calculate cuted fields
   store_values(values);

sql/sql_lex.cc

@@ -363,6 +363,8 @@ void lex_start(THD *thd)
 
   lex->is_lex_started= TRUE;
   lex->used_tables= 0;
+  lex->limit_rows_examined= 0;
+  lex->limit_rows_examined_cnt= ULONGLONG_MAX;
   DBUG_VOID_RETURN;
 }
 

sql/sql_lex.h

@@ -1947,6 +1947,22 @@ typedef struct st_lex : public Query_tables_list
     into the select_lex.
   */
   table_map  used_tables;
+  /**
+    Maximum number of rows and/or keys examined by the query, both read,
+    changed or written. This is the argument of LIMIT ROWS EXAMINED.
+    The limit is represented by two variables - the Item is needed because
+    in case of parameters we have to delay its evaluation until execution.
+    Once evaluated, its value is stored in examined_rows_limit_cnt.
+  */
+  Item *limit_rows_examined;
+  ulonglong limit_rows_examined_cnt;
+  inline void set_limit_rows_examined()
+  {
+    if (limit_rows_examined)
+      limit_rows_examined_cnt= limit_rows_examined->val_uint();
+    else
+      limit_rows_examined_cnt= ULONGLONG_MAX;
+  }
 
   st_lex();
 

sql/sql_parse.cc

@@ -5876,6 +5876,7 @@ void mysql_reset_thd_for_next_command(THD *thd, my_bool calculate_userstat)
   thd->total_warn_count=0;			// Warnings for this query
   thd->rand_used= 0;
   thd->sent_row_count= thd->examined_row_count= 0;
+  thd->accessed_rows_and_keys= 0;
 
   /* Copy data for user stats */
   if ((thd->userstat_running= calculate_userstat))

sql/sql_select.cc

@@ -289,6 +289,21 @@ bool handle_select(THD *thd, LEX *lex, select_result *result,
   res|= thd->is_error();
   if (unlikely(res))
     result->abort();
+  if (thd->killed == ABORT_QUERY)
+  {
+    /*
+      If LIMIT ROWS EXAMINED interrupted query execution, issue a warning,
+      continue with normal processing and produce an incomplete query result.
+    */
+    push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                        ER_QUERY_EXCEEDED_ROWS_EXAMINED_LIMIT,
+                        ER(ER_QUERY_EXCEEDED_ROWS_EXAMINED_LIMIT),
+                        thd->accessed_rows_and_keys,
+                        thd->lex->limit_rows_examined->val_uint());
+    thd->killed= NOT_KILLED;
+  }
+  /* Disable LIMIT ROWS EXAMINED after query execution. */
+  thd->lex->limit_rows_examined_cnt= ULONGLONG_MAX;
 
   DBUG_RETURN(res);
 }
@@ -1682,6 +1697,19 @@ int JOIN::init_execution()
   DBUG_ASSERT(!(select_options & SELECT_DESCRIBE));
   initialized= true;
 
+  /*
+    Enable LIMIT ROWS EXAMINED during query execution if:
+    (1) This JOIN is the outermost query (not a subquery or derived table)
+        This ensures that the limit is enabled when actual execution begins, and
+        not if a subquery is evaluated during optimization of the outer query.
+    (2) This JOIN is not the result of a UNION. In this case do not apply the
+        limit in order to produce the partial query result stored in the
+        UNION temp table.
+  */
+  if (!select_lex->outer_select() &&                            // (1)
+      select_lex != select_lex->master_unit()->fake_select_lex) // (2)
+    thd->lex->set_limit_rows_examined();
+
   /* Create a tmp table if distinct or if the sort is too complicated */
   if (need_tmp)
   {
@@ -15091,14 +15119,14 @@ do_select(JOIN *join,List<Item> *fields,TABLE *table,Procedure *procedure)
       error= NESTED_LOOP_NO_MORE_ROWS;
     else
       error= sub_select(join,join_tab,0);
-    if (error == NESTED_LOOP_OK || error == NESTED_LOOP_NO_MORE_ROWS)
+    if ((error == NESTED_LOOP_OK || error == NESTED_LOOP_NO_MORE_ROWS) &&
+        join->thd->killed != ABORT_QUERY)
       error= sub_select(join,join_tab,1);
     if (error == NESTED_LOOP_QUERY_LIMIT)
       error= NESTED_LOOP_OK;                    /* select_limit used */
   }
-  if (error == NESTED_LOOP_NO_MORE_ROWS)
+  if (error == NESTED_LOOP_NO_MORE_ROWS || join->thd->killed == ABORT_QUERY)
     error= NESTED_LOOP_OK;
-
   if (table == NULL)                      	// If sending data to client
   {
     /*
@@ -16652,11 +16680,6 @@ end_write(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
   TABLE *table=join->tmp_table;
   DBUG_ENTER("end_write");
 
-  if (join->thd->killed)			// Aborted by user
-  {
-    join->thd->send_kill_message();
-    DBUG_RETURN(NESTED_LOOP_KILLED);             /* purecov: inspected */
-  }
   if (!end_of_records)
   {
     copy_fields(&join->tmp_table_param);
@@ -16701,11 +16724,15 @@ end_write(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
 	  DBUG_RETURN(NESTED_LOOP_QUERY_LIMIT);
 	join->do_send_rows=0;
 	join->unit->select_limit_cnt = HA_POS_ERROR;
-	DBUG_RETURN(NESTED_LOOP_OK);
       }
     }
   }
 end:
+  if (join->thd->killed)
+  {
+    join->thd->send_kill_message();
+    DBUG_RETURN(NESTED_LOOP_KILLED);             /* purecov: inspected */
+  }
   DBUG_RETURN(NESTED_LOOP_OK);
 }
 
@@ -16723,11 +16750,6 @@ end_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
 
   if (end_of_records)
     DBUG_RETURN(NESTED_LOOP_OK);
-  if (join->thd->killed)			// Aborted by user
-  {
-    join->thd->send_kill_message();
-    DBUG_RETURN(NESTED_LOOP_KILLED);             /* purecov: inspected */
-  }
 
   join->found_records++;
   copy_fields(&join->tmp_table_param);		// Groups are copied twice.
@@ -16753,7 +16775,7 @@ end_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
       table->file->print_error(error,MYF(0));	/* purecov: inspected */
       DBUG_RETURN(NESTED_LOOP_ERROR);            /* purecov: inspected */
     }
-    DBUG_RETURN(NESTED_LOOP_OK);
+    goto end;
   }
 
   /*
@@ -16788,6 +16810,12 @@ end_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
     join->join_tab[join->top_join_tab_count-1].next_select=end_unique_update;
   }
   join->send_records++;
+end:
+  if (join->thd->killed)
+  {
+    join->thd->send_kill_message();
+    DBUG_RETURN(NESTED_LOOP_KILLED);             /* purecov: inspected */
+  }
   DBUG_RETURN(NESTED_LOOP_OK);
 }
 
@@ -16804,11 +16832,6 @@ end_unique_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
 
   if (end_of_records)
     DBUG_RETURN(NESTED_LOOP_OK);
-  if (join->thd->killed)			// Aborted by user
-  {
-    join->thd->send_kill_message();
-    DBUG_RETURN(NESTED_LOOP_KILLED);             /* purecov: inspected */
-  }
 
   init_tmptable_sum_functions(join->sum_funcs);
   copy_fields(&join->tmp_table_param);		// Groups are copied twice.
@@ -16838,6 +16861,11 @@ end_unique_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
       DBUG_RETURN(NESTED_LOOP_ERROR);            /* purecov: inspected */
     }
   }
+  if (join->thd->killed)
+  {
+    join->thd->send_kill_message();
+    DBUG_RETURN(NESTED_LOOP_KILLED);             /* purecov: inspected */
+  }
   DBUG_RETURN(NESTED_LOOP_OK);
 }
 
@@ -16851,11 +16879,6 @@ end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
   int	  idx= -1;
   DBUG_ENTER("end_write_group");
 
-  if (join->thd->killed)
-  {						// Aborted by user
-    join->thd->send_kill_message();
-    DBUG_RETURN(NESTED_LOOP_KILLED);             /* purecov: inspected */
-  }
   if (!join->first_record || end_of_records ||
       (idx=test_if_group_changed(join->group_fields)) >= 0)
   {
@@ -16889,13 +16912,13 @@ end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
 	    DBUG_RETURN(NESTED_LOOP_ERROR);
 	}
 	if (end_of_records)
-	  DBUG_RETURN(NESTED_LOOP_OK);
+	  goto end;
       }
     }
     else
     {
       if (end_of_records)
-	DBUG_RETURN(NESTED_LOOP_OK);
+        goto end;
       join->first_record=1;
       VOID(test_if_group_changed(join->group_fields));
     }
@@ -16908,13 +16931,19 @@ end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
 	DBUG_RETURN(NESTED_LOOP_ERROR);
       if (join->procedure)
 	join->procedure->add();
-      DBUG_RETURN(NESTED_LOOP_OK);
+      goto end;
     }
   }
   if (update_sum_func(join->sum_funcs))
     DBUG_RETURN(NESTED_LOOP_ERROR);
   if (join->procedure)
     join->procedure->add();
+end:
+  if (join->thd->killed)
+  {
+    join->thd->send_kill_message();
+    DBUG_RETURN(NESTED_LOOP_KILLED);             /* purecov: inspected */
+  }
   DBUG_RETURN(NESTED_LOOP_OK);
 }
 
@@ -18561,6 +18590,7 @@ remove_duplicates(JOIN *join, TABLE *entry,List<Item> &fields, Item *having)
   ulong reclength,offset;
   uint field_count;
   THD *thd= join->thd;
+
   DBUG_ENTER("remove_duplicates");
 
   entry->reginfo.lock_type=TL_WRITE;
@@ -18586,6 +18616,13 @@ remove_duplicates(JOIN *join, TABLE *entry,List<Item> &fields, Item *having)
            offset(entry->record[0]) : 0);
   reclength=entry->s->reclength-offset;
 
+  /*
+    Disable LIMIT ROWS EXAMINED in order to avoid interrupting prematurely
+    duplicate removal, and produce a possibly incomplete query result.
+  */
+  thd->lex->limit_rows_examined_cnt= ULONGLONG_MAX;
+  if (thd->killed == ABORT_QUERY)
+    thd->killed= NOT_KILLED;
   free_io_cache(entry);				// Safety
   entry->file->info(HA_STATUS_VARIABLE);
   if (entry->s->db_type() == heap_hton ||
@@ -18599,6 +18636,8 @@ remove_duplicates(JOIN *join, TABLE *entry,List<Item> &fields, Item *having)
     error=remove_dup_with_compare(join->thd, entry, first_field, offset,
 				  having);
 
+  if (join->select_lex != join->select_lex->master_unit()->fake_select_lex)
+    thd->lex->set_limit_rows_examined();
   free_blobs(first_field);
   DBUG_RETURN(error);
 }

sql/sql_union.cc

@@ -57,6 +57,8 @@ int select_union::send_data(List<Item> &values)
     unit->offset_limit_cnt--;
     return 0;
   }
+  if (thd->killed == ABORT_QUERY)
+    return 0;
   if (table->no_rows_with_nulls)
     table->null_catch_flags= CHECK_ROW_FOR_NULLS_TO_REJECT;
   fill_record(thd, table->field, values, TRUE, FALSE);
@@ -698,6 +700,20 @@ bool st_select_lex_unit::exec()
 	add_rows+= (ulonglong) (thd->limit_found_rows - (ulonglong)
 			      ((table->file->stats.records -  records_at_start)));
       }
+      if (thd->killed == ABORT_QUERY)
+      {
+        /*
+          Stop execution of the remaining queries in the UNIONS, and produce
+          the current result.
+        */
+        push_warning_printf(thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                            ER_QUERY_EXCEEDED_ROWS_EXAMINED_LIMIT,
+                            ER(ER_QUERY_EXCEEDED_ROWS_EXAMINED_LIMIT),
+                            thd->accessed_rows_and_keys,
+                            thd->lex->limit_rows_examined->val_uint());
+        thd->killed= NOT_KILLED;
+        break;
+      }
     }
   }
 
@@ -706,6 +722,11 @@ bool st_select_lex_unit::exec()
   {
     List<Item_func_match> empty_list;
     empty_list.empty();
+    /*
+      Disable LIMIT ROWS EXAMINED in order to produce the possibly incomplete
+      result of the UNION without interruption due to exceeding the limit.
+    */
+    thd->lex->limit_rows_examined_cnt= ULONGLONG_MAX;
 
     if (!thd->is_fatal_error)				// Check if EOM
     {
@@ -726,7 +747,7 @@ bool st_select_lex_unit::exec()
 					      fake_select_lex->options, result)))
 	{
 	  fake_select_lex->table_list.empty();
-	  DBUG_RETURN(TRUE);
+	  goto err;
 	}
         fake_select_lex->join->no_const_tables= TRUE;
 
@@ -798,6 +819,8 @@ bool st_select_lex_unit::exec()
     }
   }
   thd->lex->current_select= lex_select_save;
+err:
+  thd->lex->set_limit_rows_examined();
   DBUG_RETURN(saved_error);
 }
 

sql/sql_view.cc

@@ -435,6 +435,17 @@ bool mysql_create_view(THD *thd, TABLE_LIST *views,
     goto err;
   }
 
+  if (lex->limit_rows_examined)
+  {
+    /*
+      LIMIT ROWS EXAMINED is not supported inside views to avoid complicated
+      side-effects and semantics of the clause.
+    */
+    my_error(ER_NOT_SUPPORTED_YET, MYF(0), "LIMIT ROWS EXAMINED inside views");
+    res= TRUE;
+    goto err;
+  }
+
   sp_cache_invalidate();
 
   if (!lex->definer)

sql/sql_yacc.yy

@@ -865,6 +865,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
 %token  EVENTS_SYM
 %token  EVENT_SYM
 %token  EVERY_SYM                     /* SQL-2003-N */
+%token  EXAMINED_SYM
 %token  EXECUTE_SYM                   /* SQL-2003-R */
 %token  EXISTS                        /* SQL-2003-R */
 %token  EXIT_SYM
@@ -9620,6 +9621,7 @@ opt_limit_clause_init:
             SELECT_LEX *sel= lex->current_select;
             sel->offset_limit= 0;
             sel->select_limit= 0;
+	    lex->limit_rows_examined= 0;
           }
         | limit_clause {}
         ;
@@ -9631,6 +9633,8 @@ opt_limit_clause:
 
 limit_clause:
           LIMIT limit_options {}
+        | LIMIT limit_options ROWS_SYM EXAMINED_SYM limit_rows_option {}
+        | LIMIT ROWS_SYM EXAMINED_SYM limit_rows_option {}
         ;
 
 limit_options:
@@ -9682,6 +9686,13 @@ limit_option:
           }
         ;
 
+limit_rows_option:
+          limit_option
+          { 
+            LEX *lex=Lex;
+            lex->limit_rows_examined= $1;
+          }
+
 delete_limit_clause:
           /* empty */
           {
@@ -9694,6 +9705,8 @@ delete_limit_clause:
             sel->select_limit= $2;
             sel->explicit_limit= 1;
           }
+       | LIMIT ROWS_SYM EXAMINED_SYM { my_parse_error(ER(ER_SYNTAX_ERROR)); MYSQL_YYABORT; }
+       | LIMIT limit_option ROWS_SYM EXAMINED_SYM { my_parse_error(ER(ER_SYNTAX_ERROR)); MYSQL_YYABORT; }
         ;
 
 int_num:
@@ -12131,6 +12144,7 @@ keyword:
         | DO_SYM                {}
         | END                   {}
         | EXECUTE_SYM           {}
+        | EXAMINED_SYM          {}
         | FLUSH_SYM             {}
         | HANDLER_SYM           {}
         | HELP_SYM              {}
@@ -13011,6 +13025,7 @@ handler:
               MYSQL_YYABORT;
             lex->current_select->select_limit= one;
             lex->current_select->offset_limit= 0;
+            lex->limit_rows_examined= 0;
             if (!lex->current_select->add_table_to_list(lex->thd, $2, 0, 0))
               MYSQL_YYABORT;
           }