Make EXPLAIN better at displaying MRR/BKA:

- "Using MRR" is no longer shown with range access.
- Instead, both range and BKA accesses will show one of the following:
  = "Rowid-ordered scan"
  = "Key-ordered scan"
  = "Key-ordered Rowid-ordered scan"
depending on whether DS-MRR implementation will do scan keys in order, rowids in order,
or both.
- The patch also introduces a way for other storage engines/MRR implementations to
  pass information to EXPLAIN output about the properties of employed MRR scans.

mysql-test/r/ctype_collate.result

@@ -578,19 +578,19 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	s2	NULL	NULL	NULL	10	Using where
 EXPLAIN SELECT * FROM t1 WHERE s1 BETWEEN 'a' AND 'b' COLLATE latin1_german1_ci;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	s1	s1	11	NULL	2	Using index condition; Using MRR
+1	SIMPLE	t1	range	s1	s1	11	NULL	2	Using index condition; Rowid-ordered scan
 EXPLAIN SELECT * FROM t1 WHERE s2 BETWEEN 'a' AND 'b' COLLATE latin1_german1_ci;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	s2	NULL	NULL	NULL	10	Using where
 EXPLAIN SELECT * FROM t1 WHERE s1 IN  ('a','b' COLLATE latin1_german1_ci);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	s1	s1	11	NULL	2	Using index condition; Using MRR
+1	SIMPLE	t1	range	s1	s1	11	NULL	2	Using index condition; Rowid-ordered scan
 EXPLAIN SELECT * FROM t1 WHERE s2 IN  ('a','b' COLLATE latin1_german1_ci);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	s2	NULL	NULL	NULL	10	Using where
 EXPLAIN SELECT * FROM t1 WHERE s1 LIKE 'a' COLLATE latin1_german1_ci;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	s1	s1	11	NULL	1	Using index condition; Using MRR
+1	SIMPLE	t1	range	s1	s1	11	NULL	1	Using index condition; Rowid-ordered scan
 EXPLAIN SELECT * FROM t1 WHERE s2 LIKE 'a' COLLATE latin1_german1_ci;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	s2	NULL	NULL	NULL	10	Using where

mysql-test/r/index_intersect.result

@@ -74,12 +74,12 @@ EXPLAIN
 SELECT * FROM City 
 WHERE Name LIKE 'M%' AND Population > 300000;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	City	range	Population,Name	Name	35	NULL	#	Using index condition; Using where; Using MRR
+1	SIMPLE	City	range	Population,Name	Name	35	NULL	#	Using index condition; Using where; Rowid-ordered scan
 EXPLAIN
 SELECT * FROM City
 WHERE Name LIKE 'M%' AND Population > 7000000;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	City	range	Population,Name	Population	4	NULL	#	Using index condition; Using where; Using MRR
+1	SIMPLE	City	range	Population,Name	Population	4	NULL	#	Using index condition; Using where; Rowid-ordered scan
 SELECT * FROM City USE INDEX ()
 WHERE Name LIKE 'C%' AND Population > 1000000;
 ID	Name	Country	Population
@@ -371,7 +371,7 @@ EXPLAIN
 SELECT * FROM City 
 WHERE Name BETWEEN 'G' AND 'K' AND Population > 500000 AND Country LIKE 'C%';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	City	range	Population,Country,Name	Name	35	NULL	#	Using index condition; Using where; Using MRR
+1	SIMPLE	City	range	Population,Country,Name	Name	35	NULL	#	Using index condition; Using where; Rowid-ordered scan
 SELECT * FROM City USE INDEX ()
 WHERE Name BETWEEN 'M' AND 'N' AND Population > 1000000 AND Country LIKE 'C%';
 ID	Name	Country	Population
@@ -462,7 +462,7 @@ EXPLAIN
 SELECT * FROM City
 WHERE ID BETWEEN 501 AND 1000 AND Population > 700000 AND Country LIKE 'C%';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	City	range	PRIMARY,Population,Country	Population	4	NULL	#	Using index condition; Using where; Using MRR
+1	SIMPLE	City	range	PRIMARY,Population,Country	Population	4	NULL	#	Using index condition; Using where; Rowid-ordered scan
 EXPLAIN
 SELECT * FROM City
 WHERE ID BETWEEN 1 AND 500 AND Population > 1000000 AND Country LIKE 'A%';
@@ -472,7 +472,7 @@ EXPLAIN
 SELECT * FROM City 
 WHERE ID BETWEEN 2001 AND 2500 AND Population > 300000 AND Country LIKE 'H%';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	City	range	PRIMARY,Population,Country	Country	3	NULL	#	Using index condition; Using where; Using MRR
+1	SIMPLE	City	range	PRIMARY,Population,Country	Country	3	NULL	#	Using index condition; Using where; Rowid-ordered scan
 EXPLAIN
 SELECT * FROM City 
 WHERE ID BETWEEN 3701 AND 4000 AND Population > 1000000
@@ -484,7 +484,7 @@ SELECT * FROM City
 WHERE ID BETWEEN 3001 AND 4000 AND Population > 600000
 AND Country BETWEEN 'S' AND 'Z' ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	City	range	PRIMARY,Population,Country	Population	4	NULL	#	Using index condition; Using where; Using MRR
+1	SIMPLE	City	range	PRIMARY,Population,Country	Population	4	NULL	#	Using index condition; Using where; Rowid-ordered scan
 SELECT * FROM City USE INDEX ()
 WHERE ID BETWEEN 501 AND 1000 AND Population > 700000 AND Country LIKE 'C%';
 ID	Name	Country	Population
@@ -733,7 +733,7 @@ EXPLAIN
 SELECT * FROM City 
 WHERE  Name BETWEEN 'G' AND 'J' AND Population > 500000 AND Country LIKE 'C%';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	City	range	Population,Country,Name	Name	35	NULL	#	Using index condition; Using where; Using MRR
+1	SIMPLE	City	range	Population,Country,Name	Name	35	NULL	#	Using index condition; Using where; Rowid-ordered scan
 EXPLAIN
 SELECT * FROM City
 WHERE ID BETWEEN 1 AND 500 AND Population > 1000000 AND Country LIKE 'A%';
@@ -744,7 +744,7 @@ SELECT * FROM City
 WHERE ID BETWEEN 3001 AND 4000 AND Population > 600000
 AND Country BETWEEN 'S' AND 'Z';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	City	range	PRIMARY,Population,Country	Population	4	NULL	#	Using index condition; Using where; Using MRR
+1	SIMPLE	City	range	PRIMARY,Population,Country	Population	4	NULL	#	Using index condition; Using where; Rowid-ordered scan
 SELECT * FROM City WHERE
 Name LIKE 'C%' AND Population > 1000000;
 ID	Name	Country	Population
@@ -1028,7 +1028,7 @@ EXPLAIN
 SELECT * FROM t1
 WHERE (f1 < 535  OR  f1 > 985) AND ( f4='r' OR f4 LIKE 'a%' ) ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY,f4	f4	35	NULL	#	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY,f4	f4	35	NULL	#	Using index condition; Using where; Rowid-ordered scan
 SELECT * FROM t1
 WHERE (f1 < 535  OR  f1 > 985) AND ( f4='r' OR f4 LIKE 'a%' ) ;
 f1	f4	f5

mysql-test/r/index_merge_myisam.result

@@ -21,7 +21,7 @@ Table	Op	Msg_type	Msg_text
 test.t0	analyze	status	OK
 explain select * from t0 where key1 < 3 or key1 > 1020;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t0	range	i1	i1	4	NULL	78	Using index condition; Using MRR
+1	SIMPLE	t0	range	i1	i1	4	NULL	78	Using index condition; Rowid-ordered scan
 explain
 select * from t0 where key1 < 3 or key2 > 1020;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -74,7 +74,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t0	index_merge	i1,i2	i1,i2	4,4	NULL	17	Using sort_union(i1,i2); Using where
 explain select * from t0 where key2 = 45 or key1 <=> null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t0	range	i1,i2	i2	4	NULL	1	Using where; Using MRR
+1	SIMPLE	t0	range	i1,i2	i2	4	NULL	1	Using where; Rowid-ordered scan
 explain select * from t0 where key2 = 45 or key1 is not null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t0	ALL	i1,i2	NULL	NULL	NULL	1024	Using where
@@ -277,7 +277,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 explain select * from t0,t1 where t0.key1 < 3 and
 (t1.key1 = t0.key1 or t1.key8 = t0.key1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t0	range	i1	i1	4	NULL	3	Using index condition; Using MRR
+1	SIMPLE	t0	range	i1	i1	4	NULL	3	Using index condition; Rowid-ordered scan
 1	SIMPLE	t1	ALL	i1,i8	NULL	NULL	NULL	1024	Range checked for each record (index map: 0x81)
 explain select * from t1 where key1=3 or key2=4
 union select * from t1 where key1<4 or key3=5;
@@ -1379,7 +1379,7 @@ primary key (pk1, pk2)
 );
 explain select * from t1 where pk1 = 1 and pk2 < 80  and key1=0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY,key1	PRIMARY	8	NULL	7	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY,key1	PRIMARY	8	NULL	7	Using index condition; Using where; Rowid-ordered scan
 select * from t1 where pk1 = 1 and pk2 < 80  and key1=0;
 pk1	pk2	key1	key2	pktail1ok	pktail2ok	pktail3bad	pktail4bad	pktail5bad	pk2copy	badkey	filler1	filler2
 1	19	0	0	0	0	0	0	0	19	0	filler-data-19	filler2

mysql-test/r/innodb.result

@@ -1295,7 +1295,7 @@ count(*)
 623
 explain select * from t1 where c between 1 and 2500;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	c	c	5	NULL	#	Using index condition; Using MRR
+1	SIMPLE	t1	range	c	c	5	NULL	#	Using index condition; Rowid-ordered scan
 update t1 set c=a;
 explain select * from t1 where c between 1 and 2500;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

mysql-test/r/innodb_mrr.result

@@ -184,7 +184,7 @@ explain
 select * from t4 where a IS NULL and b IS NULL and (c IS NULL or c='no-such-row1'
                                                       or c='no-such-row2');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t4	range	idx1	idx1	29	NULL	16	Using index condition; Using MRR
+1	SIMPLE	t4	range	idx1	idx1	29	NULL	16	Using index condition; Rowid-ordered scan
 select * from t4 where a IS NULL and b IS NULL and (c IS NULL or c='no-such-row1'
                                                     or c='no-such-row2');
 a	b	c	filler
@@ -206,7 +206,7 @@ NULL	NULL	NULL	NULL-1
 explain 
 select * from t4 where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t4	range	idx1	idx1	29	NULL	32	Using index condition; Using MRR
+1	SIMPLE	t4	range	idx1	idx1	29	NULL	32	Using index condition; Rowid-ordered scan
 select * from t4 where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
 a	b	c	filler
 b-1	NULL	c-1	NULL-15
@@ -309,7 +309,7 @@ from t1 A, t1 B, t1 C;
 explain
 select count(length(a) + length(filler)) from t2 where a>='a-1000-a' and a <'a-1001-a';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	range	a	a	9	NULL	99	Using index condition; Using MRR
+1	SIMPLE	t2	range	a	a	9	NULL	99	Using index condition; Rowid-ordered scan
 select count(length(a) + length(filler)) from t2 where a>='a-1000-a' and a <'a-1001-a';
 count(length(a) + length(filler))
 100
@@ -319,7 +319,7 @@ filler char(10), key(d), primary key (a,b,c)) engine= innodb;
 insert into t2 select A.a, B.a, B.a, A.a, 'filler' from t1 A, t1 B;
 explain select * from t2 force index (d) where d < 10;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	range	d	d	5	NULL	#	Using index condition; Using MRR
+1	SIMPLE	t2	range	d	d	5	NULL	#	Using index condition; Rowid-ordered scan
 drop table t2;
 drop table t1;
 set @@mrr_buffer_size= @mrr_buffer_size_save;

mysql-test/r/innodb_mrr_cpk.result

@@ -25,7 +25,7 @@ This should use join buffer:
 explain select * from t1, t2 where t1.a=t2.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
-1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	8	test.t2.a	1	Using join buffer (flat, BKA join)
+1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	8	test.t2.a	1	Using join buffer (flat, BKA join); Key-ordered scan
 This output must be sorted by value of t1.a:
 select * from t1, t2 where t1.a=t2.a;
 a	b	filler	a
@@ -47,7 +47,7 @@ insert into t2 values ('a-1010=A', 1010), ('a-1030=A', 1030), ('a-1020=A', 1020)
 explain select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
-1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	28	test.t2.a,test.t2.b	1	Using join buffer (flat, BKA join)
+1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	28	test.t2.a,test.t2.b	1	Using join buffer (flat, BKA join); Key-ordered scan
 select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
 a	b	filler	a	b
 a-1010=A	1010	filler	a-1010=A	1010
@@ -57,7 +57,7 @@ insert into t2 values ('a-1030=A', 1030), ('a-1020=A', 1020);
 explain select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	5	Using where
-1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	28	test.t2.a,test.t2.b	1	Using join buffer (flat, BKA join)
+1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	28	test.t2.a,test.t2.b	1	Using join buffer (flat, BKA join); Key-ordered scan
 select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
 a	b	filler	a	b
 a-1010=A	1010	filler	a-1010=A	1010
@@ -80,7 +80,7 @@ insert into t2 values ('a-1010=A', 1010), ('a-1030=A', 1030), ('a-1020=A', 1020)
 explain select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
-1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	30	test.t2.a,test.t2.b	1	Using index condition(BKA); Using join buffer (flat, BKA join)
+1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	30	test.t2.a,test.t2.b	1	Using index condition(BKA); Using join buffer (flat, BKA join); Key-ordered scan
 select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
 a	b	filler	a	b
 a-1010=A	1010	filler	a-1010=A	1010
@@ -89,7 +89,7 @@ a-1030=A	1030	filler	a-1030=A	1030
 explain select * from t1, t2 where t1.a=t2.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
-1	SIMPLE	t1	ref	PRIMARY	PRIMARY	26	test.t2.a	1	Using index condition(BKA); Using join buffer (flat, BKA join)
+1	SIMPLE	t1	ref	PRIMARY	PRIMARY	26	test.t2.a	1	Using index condition(BKA); Using join buffer (flat, BKA join); Key-ordered scan
 select * from t1, t2 where t1.a=t2.a;
 a	b	filler	a	b
 a-1010=A	1010	filler	a-1010=A	1010
@@ -109,7 +109,7 @@ insert into t2 values (11,33), (11,22), (11,11);
 explain select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
-1	SIMPLE	t1	ref	PRIMARY	PRIMARY	8	test.t2.a,test.t2.b	1	Using join buffer (flat, BKA join)
+1	SIMPLE	t1	ref	PRIMARY	PRIMARY	8	test.t2.a,test.t2.b	1	Using join buffer (flat, BKA join); Key-ordered scan
 select * from t1, t2 where t1.a=t2.a and t1.b=t2.b;
 a	b	c	filler	a	b
 11	11	11	filler	11	11
@@ -131,14 +131,14 @@ set join_cache_level=6;
 explain select * from t1, t2 where t1.a=t2.a and t2.b + t1.b > 100;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
-1	SIMPLE	t1	ref	PRIMARY	PRIMARY	4	test.t2.a	1	Using index condition(BKA); Using join buffer (flat, BKA join)
+1	SIMPLE	t1	ref	PRIMARY	PRIMARY	4	test.t2.a	1	Using index condition(BKA); Using join buffer (flat, BKA join); Key-ordered scan
 select * from t1, t2 where t1.a=t2.a and t2.b + t1.b > 100;
 a	b	c	filler	a	b
 set optimizer_switch='index_condition_pushdown=off';
 explain select * from t1, t2 where t1.a=t2.a and t2.b + t1.b > 100;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
-1	SIMPLE	t1	ref	PRIMARY	PRIMARY	4	test.t2.a	1	Using where; Using join buffer (flat, BKA join)
+1	SIMPLE	t1	ref	PRIMARY	PRIMARY	4	test.t2.a	1	Using where; Using join buffer (flat, BKA join); Key-ordered scan
 select * from t1, t2 where t1.a=t2.a and t2.b + t1.b > 100;
 a	b	c	filler	a	b
 set optimizer_switch='index_condition_pushdown=on';

mysql-test/r/join_outer_jcl6.result

@@ -102,7 +102,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 explain select t1.*,t2.* from t1 left join t2 on t1.a=t2.a where isnull(t2.a)=1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	7	
-1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	8	test.t1.a	1	Using where; Using join buffer (flat, BKA join)
+1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	8	test.t1.a	1	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 select t1.*,t2.*,t3.a from t1 left join t2 on (t1.a=t2.a) left join t1 as t3 on (t2.a=t3.a);
 grp	a	c	id	a	c	d	a
 1	1	a	1	1	a	1	1
@@ -745,13 +745,13 @@ explain select s.*, '*', m.*, (s.match_1_h - m.home) UUX from
 order by m.match_id desc;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	s	ALL	NULL	NULL	NULL	NULL	10	Using temporary; Using filesort
-1	SIMPLE	m	const	match_id,match_id_2	match_id	1	const	1	Using join buffer (flat, BKA join)
+1	SIMPLE	m	const	match_id,match_id_2	match_id	1	const	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 explain select s.*, '*', m.*, (s.match_1_h - m.home) UUX from 
 (t2 s left join t1 m on m.match_id = 1) 
 order by UUX desc;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	s	ALL	NULL	NULL	NULL	NULL	10	Using temporary; Using filesort
-1	SIMPLE	m	const	match_id,match_id_2	match_id	1	const	1	Using join buffer (flat, BKA join)
+1	SIMPLE	m	const	match_id,match_id_2	match_id	1	const	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 select s.*, '*', m.*, (s.match_1_h - m.home) UUX from 
 (t2 s left join t1 m on m.match_id = 1) 
 order by UUX desc;
@@ -771,7 +771,7 @@ t2 s straight_join t1 m where m.match_id = 1
 order by UUX desc;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	s	ALL	NULL	NULL	NULL	NULL	10	Using temporary; Using filesort
-1	SIMPLE	m	const	match_id,match_id_2	match_id	1	const	1	Using join buffer (flat, BKA join)
+1	SIMPLE	m	const	match_id,match_id_2	match_id	1	const	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 select s.*, '*', m.*, (s.match_1_h - m.home) UUX from 
 t2 s straight_join t1 m where m.match_id = 1 
 order by UUX desc;
@@ -1134,15 +1134,15 @@ a	b	a	b
 EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a = t2.a OR t1.a = t2.b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	PRIMARY	NULL	NULL	NULL	4	
-1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.a	1	Using join buffer (flat, BKA join)
+1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.a	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a IN(t2.a, t2.b);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	PRIMARY	NULL	NULL	NULL	4	Using where
-1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.a	1	Using join buffer (flat, BKA join)
+1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.a	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 EXPLAIN SELECT * FROM t1 LEFT JOIN t2 ON t1.a = t2.a WHERE t1.a > IF(t1.a = t2.b-2, t2.b, t2.b-1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ALL	PRIMARY	NULL	NULL	NULL	4	Using where
-1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.a	1	Using join buffer (flat, BKA join)
+1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.a	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 DROP TABLE t1,t2;
 DROP VIEW IF EXISTS v1,v2;
 DROP TABLE IF EXISTS t1,t2;
@@ -1231,7 +1231,7 @@ EXPLAIN
 SELECT t1.id, a FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.b IS NULL;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	
-1	SIMPLE	t2	ref	idx	idx	4	test.t1.id	2	Using where; Not exists; Using join buffer (flat, BKA join)
+1	SIMPLE	t2	ref	idx	idx	4	test.t1.id	2	Using where; Not exists; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 flush status;
 SELECT t1.id, a FROM t1 LEFT JOIN t2 ON t1.id=t2.id WHERE t2.b IS NULL;
 id	a

mysql-test/r/key_cache.result

@@ -628,7 +628,7 @@ select p from t1 where p between 1010 and 1020;
 p
 explain select i from t2 where p between 1010 and 1020;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	range	PRIMARY	PRIMARY	4	NULL	28	Using index condition; Using MRR
+1	SIMPLE	t2	range	PRIMARY	PRIMARY	4	NULL	28	Using index condition; Rowid-ordered scan
 select i from t2 where p between 1010 and 1020;
 i
 1

mysql-test/r/maria_mrr.result

@@ -185,7 +185,7 @@ explain
 select * from t4 where a IS NULL and b IS NULL and (c IS NULL or c='no-such-row1'
                                                       or c='no-such-row2');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t4	range	idx1	idx1	29	NULL	16	Using index condition; Using MRR
+1	SIMPLE	t4	range	idx1	idx1	29	NULL	16	Using index condition; Rowid-ordered scan
 select * from t4 where a IS NULL and b IS NULL and (c IS NULL or c='no-such-row1'
                                                     or c='no-such-row2');
 a	b	c	filler
@@ -207,7 +207,7 @@ NULL	NULL	NULL	NULL-1
 explain 
 select * from t4 where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t4	range	idx1	idx1	29	NULL	32	Using index condition; Using MRR
+1	SIMPLE	t4	range	idx1	idx1	29	NULL	32	Using index condition; Rowid-ordered scan
 select * from t4 where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
 a	b	c	filler
 b-1	NULL	c-1	NULL-15
@@ -395,7 +395,7 @@ WHERE
 table1.col_varchar_1024_latin1_key = table2.col_varchar_10_latin1 AND table1.pk<>0 ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	table2	ALL	NULL	NULL	NULL	NULL	2	Using where
-1	SIMPLE	table1	ref	PRIMARY,col_varchar_1024_latin1_key	col_varchar_1024_latin1_key	1027	test.table2.col_varchar_10_latin1	2	Using index condition(BKA); Using where; Using join buffer (flat, BKA join)
+1	SIMPLE	table1	ref	PRIMARY,col_varchar_1024_latin1_key	col_varchar_1024_latin1_key	1027	test.table2.col_varchar_10_latin1	2	Using index condition(BKA); Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 SELECT count(*)
 FROM t1 AS table1, t2 AS table2
 WHERE

mysql-test/r/merge.result

@@ -673,7 +673,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 EXPLAIN SELECT * FROM t1 WHERE fileset_id = 2
 AND file_code BETWEEN '0000000115' AND '0000000120' LIMIT 1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY,files	PRIMARY	35	NULL	5	Using index condition; Using MRR
+1	SIMPLE	t1	range	PRIMARY,files	PRIMARY	35	NULL	5	Using index condition; Rowid-ordered scan
 EXPLAIN SELECT * FROM t2 WHERE fileset_id = 2
 AND file_code = '0000000115' LIMIT 1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

mysql-test/r/mix2_myisam.result

@@ -1114,11 +1114,11 @@ count(*)
 29267
 explain select * from t1 where c between 1 and 2500;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	c	c	5	NULL	#	Using index condition; Using MRR
+1	SIMPLE	t1	range	c	c	5	NULL	#	Using index condition; Rowid-ordered scan
 update t1 set c=a;
 explain select * from t1 where c between 1 and 2500;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	c	c	5	NULL	#	Using index condition; Using MRR
+1	SIMPLE	t1	range	c	c	5	NULL	#	Using index condition; Rowid-ordered scan
 drop table t1,t2;
 create table t1 (id int primary key auto_increment, fk int, index index_fk (fk)) engine=MyISAM;
 insert into t1 (id) values (null),(null),(null),(null),(null);

mysql-test/r/myisam.result

@@ -368,7 +368,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	a	NULL	NULL	NULL	5	Using where
 explain select * from t1 force index (a) where a=0 or a=2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	4	NULL	4	Using index condition; Using MRR
+1	SIMPLE	t1	range	a	a	4	NULL	4	Using index condition; Rowid-ordered scan
 explain select * from t1 where c=1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	c,c_2	c	5	const	1	

mysql-test/r/myisam_mrr.result

@@ -186,7 +186,7 @@ explain
 select * from t4 where a IS NULL and b IS NULL and (c IS NULL or c='no-such-row1'
                                                       or c='no-such-row2');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t4	range	idx1	idx1	29	NULL	10	Using index condition; Using MRR
+1	SIMPLE	t4	range	idx1	idx1	29	NULL	10	Using index condition; Rowid-ordered scan
 select * from t4 where a IS NULL and b IS NULL and (c IS NULL or c='no-such-row1'
                                                     or c='no-such-row2');
 a	b	c	filler
@@ -208,7 +208,7 @@ NULL	NULL	NULL	NULL-1
 explain 
 select * from t4 where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t4	range	idx1	idx1	29	NULL	21	Using index condition; Using MRR
+1	SIMPLE	t4	range	idx1	idx1	29	NULL	21	Using index condition; Rowid-ordered scan
 select * from t4 where (a ='b-1' or a='bb-1') and b IS NULL and (c='c-1' or c='cc-2');
 a	b	c	filler
 b-1	NULL	c-1	NULL-15
@@ -403,16 +403,16 @@ insert into t1 select A.a + 10 *(B.a + 10*C.a), A.a + 10 *(B.a + 10*C.a) from t0
 A query that will use ICP: 
 explain select * from t1 where a < 20;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	5	NULL	20	Using index condition; Using MRR
+1	SIMPLE	t1	range	a	a	5	NULL	20	Using index condition; Rowid-ordered scan
 set @save_optimizer_switch=@@optimizer_switch;
 set optimizer_switch='index_condition_pushdown=off';
 explain select * from t1 where a < 20;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	5	NULL	20	Using where; Using MRR
+1	SIMPLE	t1	range	a	a	5	NULL	20	Using where; Rowid-ordered scan
 set optimizer_switch='index_condition_pushdown=on';
 explain select * from t1 where a < 20;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	5	NULL	20	Using index condition; Using MRR
+1	SIMPLE	t1	range	a	a	5	NULL	20	Using index condition; Rowid-ordered scan
 set optimizer_switch=@save_optimizer_switch;
 # 
 # BUG#629684: Unreachable code in multi_range_read.cc in maria-5.3-dsmrr-cpk
@@ -426,7 +426,7 @@ explain
 select * from t0, t1 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	5	
-1	SIMPLE	t1	ref	a	a	5	test.t0.a	1	Using index condition(BKA); Using join buffer (flat, BKA join)
+1	SIMPLE	t1	ref	a	a	5	test.t0.a	1	Using index condition(BKA); Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 select * from t0, t1 where t0.a<=>t1.a;
 a	a	b
 0	0	0
@@ -504,7 +504,7 @@ table3.col_varchar_key = table2.col_varchar_nokey AND
 table3.pk<>0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	table2	ALL	col_varchar_key	NULL	NULL	NULL	20	Using where
-1	SIMPLE	table3	ref	PRIMARY,col_varchar_key	col_varchar_key	3	test.table2.col_varchar_key	3	Using where; Using join buffer (flat, BKA join)
+1	SIMPLE	table3	ref	PRIMARY,col_varchar_key	col_varchar_key	3	test.table2.col_varchar_key	3	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 set join_cache_level= @save_join_cache_level;
 set join_buffer_size= @save_join_buffer_size;
 drop table t1;

mysql-test/r/null.result

@@ -148,10 +148,10 @@ insert into t1 values
 (7,7), (8,8), (9,9), (10,10), (11,11), (12,12);
 explain select * from t1 where a between 2 and 3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	idx	idx	4	NULL	2	Using index condition; Using MRR
+1	SIMPLE	t1	range	idx	idx	4	NULL	2	Using index condition; Rowid-ordered scan
 explain select * from t1 where a between 2 and 3 or b is null;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	idx	idx	4	NULL	2	Using index condition; Using MRR
+1	SIMPLE	t1	range	idx	idx	4	NULL	2	Using index condition; Rowid-ordered scan
 drop table t1;
 select cast(NULL as signed);
 cast(NULL as signed)

mysql-test/r/order_by.result

@@ -611,7 +611,7 @@ DS-MRR: use two IGNORE INDEX queries, otherwise we get cost races, because
 DS-MRR: records_in_range/read_time return the same numbers for all three indexes
 EXPLAIN SELECT * FROM t1 IGNORE INDEX (LongField, StringField) WHERE FieldKey > '2' ORDER BY LongVal;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	FieldKey	FieldKey	38	NULL	4	Using index condition; Using MRR; Using filesort
+1	SIMPLE	t1	range	FieldKey	FieldKey	38	NULL	4	Using index condition; Rowid-ordered scan; Using filesort
 EXPLAIN SELECT * FROM t1 IGNORE INDEX (FieldKey, LongField) WHERE FieldKey > '2' ORDER BY LongVal;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	StringField	StringField	38	NULL	4	Using where; Using filesort
@@ -1112,7 +1112,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	index	k2	k3	5	NULL	73	Using where
 EXPLAIN SELECT id,c3 FROM t2 WHERE c2 BETWEEN 20 AND 30 ORDER BY c3 LIMIT 4000;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	range	k2	k2	5	NULL	386	Using index condition; Using where; Using MRR; Using filesort
+1	SIMPLE	t2	range	k2	k2	5	NULL	386	Using index condition; Using where; Rowid-ordered scan; Using filesort
 SELECT id,c3 FROM t2 WHERE c2=11 ORDER BY c3 LIMIT 20;
 id	c3
 6	14
@@ -1607,19 +1607,19 @@ INSERT INTO t2 SELECT a+4, b FROM t2;
 EXPLAIN 
 SELECT * FROM t1 FORCE INDEX FOR ORDER BY (a), t2 WHERE t1.a < 2 ORDER BY t1.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	5	NULL	2	Using index condition; Using MRR; Using temporary; Using filesort
+1	SIMPLE	t1	range	a	a	5	NULL	2	Using index condition; Rowid-ordered scan; Using temporary; Using filesort
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
 # should have "using filesort"
 EXPLAIN 
 SELECT * FROM t1 USE INDEX FOR ORDER BY (a), t2 WHERE t1.a < 2 ORDER BY t1.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	5	NULL	2	Using index condition; Using MRR; Using temporary; Using filesort
+1	SIMPLE	t1	range	a	a	5	NULL	2	Using index condition; Rowid-ordered scan; Using temporary; Using filesort
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
 # should have "using filesort"
 EXPLAIN 
 SELECT * FROM t1 FORCE INDEX FOR JOIN (a), t2 WHERE t1.a < 2 ORDER BY t1.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	5	NULL	2	Using index condition; Using MRR; Using temporary; Using filesort
+1	SIMPLE	t1	range	a	a	5	NULL	2	Using index condition; Rowid-ordered scan; Using temporary; Using filesort
 1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	10	Using join buffer (flat, BNL join)
 DROP TABLE t1, t2;
 #

mysql-test/r/ps_1general.result

@@ -465,9 +465,9 @@ def					key	253	64	7	Y	0	31	8
 def					key_len	253	4096	1	Y	0	31	8
 def					ref	253	2048	0	Y	0	31	8
 def					rows	8	10	1	Y	32928	0	63
-def					Extra	253	255	48	N	1	31	8
+def					Extra	253	255	57	N	1	31	8
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	3	Using index condition; Using MRR; Using filesort
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	3	Using index condition; Rowid-ordered scan; Using filesort
 drop table if exists t2;
 create table t2 (id smallint, name varchar(20)) ;
 prepare stmt1 from ' insert into t2 values(?, ?) ' ;

mysql-test/r/range.result

@@ -221,27 +221,27 @@ update t1 set y=x;
 explain select * from t1, t1 t2 where t1.y = 8 and t2.x between 7 and t1.y+0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	y	y	5	const	1	
-1	SIMPLE	t2	range	x	x	5	NULL	2	Using index condition; Using MRR; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	range	x	x	5	NULL	2	Using index condition; Rowid-ordered scan; Using join buffer (flat, BNL join)
 explain select * from t1, t1 t2 where t1.y = 8 and t2.x >= 7 and t2.x <= t1.y+0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	y	y	5	const	1	
-1	SIMPLE	t2	range	x	x	5	NULL	2	Using index condition; Using MRR; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	range	x	x	5	NULL	2	Using index condition; Rowid-ordered scan; Using join buffer (flat, BNL join)
 explain select * from t1, t1 t2 where t1.y = 2 and t2.x between t1.y-1 and t1.y+1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	y	y	5	const	1	
-1	SIMPLE	t2	range	x	x	5	NULL	3	Using index condition; Using MRR; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	range	x	x	5	NULL	3	Using index condition; Rowid-ordered scan; Using join buffer (flat, BNL join)
 explain select * from t1, t1 t2 where t1.y = 2 and t2.x >= t1.y-1 and t2.x <= t1.y+1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	y	y	5	const	1	
-1	SIMPLE	t2	range	x	x	5	NULL	3	Using index condition; Using MRR; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	range	x	x	5	NULL	3	Using index condition; Rowid-ordered scan; Using join buffer (flat, BNL join)
 explain select * from t1, t1 t2 where t1.y = 2 and t2.x between 0 and t1.y;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	y	y	5	const	1	
-1	SIMPLE	t2	range	x	x	5	NULL	2	Using index condition; Using MRR; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	range	x	x	5	NULL	2	Using index condition; Rowid-ordered scan; Using join buffer (flat, BNL join)
 explain select * from t1, t1 t2 where t1.y = 2 and t2.x >= 0 and t2.x <= t1.y;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	y	y	5	const	1	
-1	SIMPLE	t2	range	x	x	5	NULL	2	Using index condition; Using MRR; Using join buffer (flat, BNL join)
+1	SIMPLE	t2	range	x	x	5	NULL	2	Using index condition; Rowid-ordered scan; Using join buffer (flat, BNL join)
 explain select count(*) from t1 where x in (1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	x	x	5	const	1	Using index
@@ -276,7 +276,7 @@ INSERT INTO t1 VALUES
 (33,5),(33,5),(33,5),(33,5),(34,5),(35,5);
 EXPLAIN SELECT * FROM t1 WHERE a IN(1,2) AND b=5;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a,b	a	5	NULL	2	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	a,b	a	5	NULL	2	Using index condition; Using where; Rowid-ordered scan
 SELECT * FROM t1 WHERE a IN(1,2) AND b=5;
 a	b
 DROP TABLE t1;
@@ -421,19 +421,19 @@ test.t1	analyze	status	OK
 test.t2	analyze	status	Table is already up to date
 explain select * from t1, t2  where t1.uid=t2.uid AND t1.uid > 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	uid_index	uid_index	4	NULL	112	Using index condition; Using MRR
+1	SIMPLE	t1	range	uid_index	uid_index	4	NULL	112	Using index condition; Rowid-ordered scan
 1	SIMPLE	t2	ref	uid_index	uid_index	4	test.t1.uid	38	
 explain select * from t1, t2  where t1.uid=t2.uid AND t2.uid > 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	uid_index	uid_index	4	NULL	112	Using index condition; Using MRR
+1	SIMPLE	t1	range	uid_index	uid_index	4	NULL	112	Using index condition; Rowid-ordered scan
 1	SIMPLE	t2	ref	uid_index	uid_index	4	test.t1.uid	38	
 explain select * from t1, t2  where t1.uid=t2.uid AND t1.uid != 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	uid_index	uid_index	4	NULL	113	Using index condition; Using MRR
+1	SIMPLE	t1	range	uid_index	uid_index	4	NULL	113	Using index condition; Rowid-ordered scan
 1	SIMPLE	t2	ref	uid_index	uid_index	4	test.t1.uid	38	
 explain select * from t1, t2  where t1.uid=t2.uid AND t2.uid != 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	uid_index	uid_index	4	NULL	113	Using index condition; Using MRR
+1	SIMPLE	t1	range	uid_index	uid_index	4	NULL	113	Using index condition; Rowid-ordered scan
 1	SIMPLE	t2	ref	uid_index	uid_index	4	test.t1.uid	38	
 select * from t1, t2  where t1.uid=t2.uid AND t1.uid > 0;
 id	name	uid	id	name	uid
@@ -618,10 +618,10 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ref	a	a	11	const	2	Using index condition
 explain select * from t1 where a=binary 'aaa';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	11	NULL	2	Using index condition; Using MRR
+1	SIMPLE	t1	range	a	a	11	NULL	2	Using index condition; Rowid-ordered scan
 explain select * from t1 where a='aaa' collate latin1_bin;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	11	NULL	2	Using index condition; Using MRR
+1	SIMPLE	t1	range	a	a	11	NULL	2	Using index condition; Rowid-ordered scan
 explain select * from t1 where a='aaa' collate latin1_german1_ci;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	ALL	a	NULL	NULL	NULL	9	Using where
@@ -878,10 +878,10 @@ INSERT INTO t1 VALUES
 (55,'C'), (56,'C'), (57,'C'), (58,'C'), (59,'C'), (60,'C');
 EXPLAIN SELECT * FROM t1 WHERE status <> 'A' AND status <> 'B';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	status	status	23	NULL	11	Using index condition; Using MRR
+1	SIMPLE	t1	range	status	status	23	NULL	11	Using index condition; Rowid-ordered scan
 EXPLAIN SELECT * FROM t1 WHERE status NOT IN ('A','B');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	status	status	23	NULL	11	Using index condition; Using MRR
+1	SIMPLE	t1	range	status	status	23	NULL	11	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE status <> 'A' AND status <> 'B';
 id	status
 53	C
@@ -910,10 +910,10 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	range	status	status	23	NULL	11	Using where; Using index
 EXPLAIN SELECT * FROM t1 WHERE status NOT BETWEEN 'A' AND 'B';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	status	status	23	NULL	10	Using index condition; Using MRR
+1	SIMPLE	t1	range	status	status	23	NULL	10	Using index condition; Rowid-ordered scan
 EXPLAIN SELECT * FROM t1 WHERE status < 'A' OR status > 'B';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	status	status	23	NULL	10	Using index condition; Using MRR
+1	SIMPLE	t1	range	status	status	23	NULL	10	Using index condition; Rowid-ordered scan
 SELECT * FROM t1 WHERE status NOT BETWEEN 'A' AND 'B';
 id	status
 53	C
@@ -1014,10 +1014,10 @@ create table t2 (a varchar(10), filler char(200), key(a));
 insert into t2 select * from t1;
 explain select * from t1 where a between 'a' and 'a ';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	13	NULL	#	Using index condition; Using MRR
+1	SIMPLE	t1	range	a	a	13	NULL	#	Using index condition; Rowid-ordered scan
 explain select * from t1 where a = 'a' or a='a ';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	13	NULL	#	Using index condition; Using MRR
+1	SIMPLE	t1	range	a	a	13	NULL	#	Using index condition; Rowid-ordered scan
 explain select * from t2 where a between 'a' and 'a ';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	ref	a	a	13	const	#	Using index condition
@@ -1027,7 +1027,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 update t1 set a='b' where a<>'a';
 explain select * from t1 where a not between 'b' and 'b';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	a	a	13	NULL	#	Using index condition; Using MRR
+1	SIMPLE	t1	range	a	a	13	NULL	#	Using index condition; Rowid-ordered scan
 select a, hex(filler) from t1 where a not between 'b' and 'b';
 a	hex(filler)
 a	0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
@@ -1071,10 +1071,10 @@ id	b	c
 0	3	4
 EXPLAIN  SELECT * FROM t1 WHERE b<=3 AND 3<=c;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	idx1,idx2	idx2	4	NULL	3	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	idx1,idx2	idx2	4	NULL	3	Using index condition; Using where; Rowid-ordered scan
 EXPLAIN  SELECT * FROM t1 WHERE 3 BETWEEN b AND c;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	idx1,idx2	idx2	4	NULL	3	Using where; Using MRR
+1	SIMPLE	t1	range	idx1,idx2	idx2	4	NULL	3	Using where; Rowid-ordered scan
 SELECT * FROM t1 WHERE 0 < b OR 0 > c;
 id	b	c
 0	3	4
@@ -1151,7 +1151,7 @@ INSERT INTO t1 VALUES
 This must use range access:
 explain select * from t1 where dateval >= '2007-01-01 00:00:00' and dateval <= '2007-01-02 23:59:59';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	dateval	dateval	4	NULL	2	Using index condition; Using MRR
+1	SIMPLE	t1	range	dateval	dateval	4	NULL	2	Using index condition; Rowid-ordered scan
 drop table t1;
 CREATE TABLE t1 (
 a varchar(32), index (a)

mysql-test/r/select.result

@@ -3417,7 +3417,7 @@ SELECT t2.sku, t2.sppr, t2.name, t1.sku, t1.pr
 FROM t2, t1 WHERE t2.sku=20 AND (t2.sku=t1.sku OR t2.sppr=t1.sku);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	2	Using index condition; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	2	Using index condition; Rowid-ordered scan
 DROP TABLE t1,t2;
 CREATE TABLE t1 (i TINYINT UNSIGNED NOT NULL);
 INSERT t1 SET i = 0;
@@ -3453,7 +3453,7 @@ In next EXPLAIN, B.rows must be exactly 10:
 explain select * from t2 A, t2 B where A.a=5 and A.b=5 and A.C<5
 and B.a=5 and B.b=A.e and (B.b =1 or B.b = 3 or B.b=5);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	A	range	PRIMARY	PRIMARY	12	NULL	4	Using index condition; Using where; Using MRR
+1	SIMPLE	A	range	PRIMARY	PRIMARY	12	NULL	4	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	B	ref	PRIMARY	PRIMARY	8	const,test.A.e	10	
 drop table t1, t2;
 CREATE TABLE t1 (a int PRIMARY KEY, b int, INDEX(b));
@@ -3467,12 +3467,12 @@ INSERT INTO t2 VALUES
 EXPLAIN
 SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY,b	b	5	NULL	3	Using index condition; Using MRR
+1	SIMPLE	t1	range	PRIMARY,b	b	5	NULL	3	Using index condition; Rowid-ordered scan
 1	SIMPLE	t2	ref	c	c	5	test.t1.a	2	
 EXPLAIN
 SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6 AND a > 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY,b	b	5	NULL	3	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY,b	b	5	NULL	3	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t2	ref	c	c	5	test.t1.a	2	
 DROP TABLE t1, t2;
 create table t1 (
@@ -3562,19 +3562,19 @@ EXPLAIN SELECT t2.*
 FROM t1 JOIN t2 ON t2.fk=t1.pk
 WHERE t2.fk < 'c' AND t2.pk=t1.fk;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	3	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	3	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	18	test.t1.fk	1	Using where
 EXPLAIN SELECT t2.* 
 FROM t1 JOIN t2 ON t2.fk=t1.pk 
 WHERE t2.fk BETWEEN 'a' AND 'b' AND t2.pk=t1.fk;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	2	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	2	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	18	test.t1.fk	1	Using where
 EXPLAIN SELECT t2.* 
 FROM t1 JOIN t2 ON t2.fk=t1.pk 
 WHERE t2.fk IN ('a','b') AND t2.pk=t1.fk;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	2	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	2	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	18	test.t1.fk	1	Using where
 DROP TABLE t1,t2;
 CREATE TABLE t1 (a int, b varchar(20) NOT NULL, PRIMARY KEY(a));
@@ -3608,7 +3608,7 @@ WHERE t1.id = 8 AND t2.i BETWEEN t1.b AND t1.e AND
 t3.a=t2.a AND t3.c IN ('bb','ee');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t2	range	si	si	5	NULL	4	Using index condition; Using where; Using MRR
+1	SIMPLE	t2	range	si	si	5	NULL	4	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t3	eq_ref	PRIMARY,ci	PRIMARY	4	test.t2.a	1	Using where
 EXPLAIN
 SELECT t3.a FROM t1,t2,t3
@@ -3616,7 +3616,7 @@ WHERE t1.id = 8 AND t2.i BETWEEN t1.b AND t1.e AND
 t3.a=t2.a AND t3.c IN ('bb','ee') ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t2	range	si,ai	si	5	NULL	4	Using index condition; Using where; Using MRR
+1	SIMPLE	t2	range	si,ai	si	5	NULL	4	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t3	eq_ref	PRIMARY,ci	PRIMARY	4	test.t2.a	1	Using where
 EXPLAIN 
 SELECT t3.a FROM t1,t2 FORCE INDEX (si),t3
@@ -3624,7 +3624,7 @@ WHERE t1.id = 8 AND (t2.i=t1.b OR t2.i=t1.e) AND t3.a=t2.a AND
 t3.c IN ('bb','ee');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t2	range	si	si	5	NULL	2	Using index condition; Using where; Using MRR
+1	SIMPLE	t2	range	si	si	5	NULL	2	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t3	eq_ref	PRIMARY,ci	PRIMARY	4	test.t2.a	1	Using where
 EXPLAIN 
 SELECT t3.a FROM t1,t2,t3
@@ -3632,7 +3632,7 @@ WHERE t1.id = 8 AND (t2.i=t1.b OR t2.i=t1.e) AND t3.a=t2.a AND
 t3.c IN ('bb','ee');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t2	range	si,ai	si	5	NULL	2	Using index condition; Using where; Using MRR
+1	SIMPLE	t2	range	si,ai	si	5	NULL	2	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t3	eq_ref	PRIMARY,ci	PRIMARY	4	test.t2.a	1	Using where
 DROP TABLE t1,t2,t3;
 CREATE TABLE t1 ( f1 int primary key, f2 int, f3 int, f4 int, f5 int, f6 int, checked_out int);
@@ -3752,7 +3752,7 @@ AND t1.ts BETWEEN t2.dt1 AND t2.dt2
 AND t1.ts BETWEEN "2006-01-01" AND "2006-12-31";
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t1	range	ts	ts	4	NULL	1	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	ts	ts	4	NULL	1	Using index condition; Using where; Rowid-ordered scan
 Warnings:
 Warning	1292	Incorrect datetime value: '2999-12-31 00:00:00' for column 'ts' at row 1
 SELECT * FROM t1 LEFT JOIN t2 ON (t1.a=t2.a) WHERE t1.a=30
@@ -4376,12 +4376,12 @@ CREATE TABLE t1 (a INT KEY, b INT);
 INSERT INTO t1 VALUES (1,1), (2,2), (3,3), (4,4);
 EXPLAIN EXTENDED SELECT a, b FROM t1 WHERE a > 1 AND a = b LIMIT 2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	3	100.00	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	3	100.00	Using index condition; Using where; Rowid-ordered scan
 Warnings:
 Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = `test`.`t1`.`a`) and (`test`.`t1`.`a` > 1)) limit 2
 EXPLAIN EXTENDED SELECT a, b FROM t1 WHERE a > 1 AND b = a LIMIT 2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	3	100.00	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	3	100.00	Using index condition; Using where; Rowid-ordered scan
 Warnings:
 Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = `test`.`t1`.`a`) and (`test`.`t1`.`a` > 1)) limit 2
 DROP TABLE t1;

mysql-test/r/select_pkeycache.result

@@ -3417,7 +3417,7 @@ SELECT t2.sku, t2.sppr, t2.name, t1.sku, t1.pr
 FROM t2, t1 WHERE t2.sku=20 AND (t2.sku=t1.sku OR t2.sppr=t1.sku);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	2	Using index condition; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	2	Using index condition; Rowid-ordered scan
 DROP TABLE t1,t2;
 CREATE TABLE t1 (i TINYINT UNSIGNED NOT NULL);
 INSERT t1 SET i = 0;
@@ -3453,7 +3453,7 @@ In next EXPLAIN, B.rows must be exactly 10:
 explain select * from t2 A, t2 B where A.a=5 and A.b=5 and A.C<5
 and B.a=5 and B.b=A.e and (B.b =1 or B.b = 3 or B.b=5);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	A	range	PRIMARY	PRIMARY	12	NULL	4	Using index condition; Using where; Using MRR
+1	SIMPLE	A	range	PRIMARY	PRIMARY	12	NULL	4	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	B	ref	PRIMARY	PRIMARY	8	const,test.A.e	10	
 drop table t1, t2;
 CREATE TABLE t1 (a int PRIMARY KEY, b int, INDEX(b));
@@ -3467,12 +3467,12 @@ INSERT INTO t2 VALUES
 EXPLAIN
 SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY,b	b	5	NULL	3	Using index condition; Using MRR
+1	SIMPLE	t1	range	PRIMARY,b	b	5	NULL	3	Using index condition; Rowid-ordered scan
 1	SIMPLE	t2	ref	c	c	5	test.t1.a	2	
 EXPLAIN
 SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6 AND a > 0;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY,b	b	5	NULL	3	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY,b	b	5	NULL	3	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t2	ref	c	c	5	test.t1.a	2	
 DROP TABLE t1, t2;
 create table t1 (
@@ -3562,19 +3562,19 @@ EXPLAIN SELECT t2.*
 FROM t1 JOIN t2 ON t2.fk=t1.pk
 WHERE t2.fk < 'c' AND t2.pk=t1.fk;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	3	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	3	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	18	test.t1.fk	1	Using where
 EXPLAIN SELECT t2.* 
 FROM t1 JOIN t2 ON t2.fk=t1.pk 
 WHERE t2.fk BETWEEN 'a' AND 'b' AND t2.pk=t1.fk;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	2	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	2	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	18	test.t1.fk	1	Using where
 EXPLAIN SELECT t2.* 
 FROM t1 JOIN t2 ON t2.fk=t1.pk 
 WHERE t2.fk IN ('a','b') AND t2.pk=t1.fk;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	2	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	12	NULL	2	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t2	eq_ref	PRIMARY	PRIMARY	18	test.t1.fk	1	Using where
 DROP TABLE t1,t2;
 CREATE TABLE t1 (a int, b varchar(20) NOT NULL, PRIMARY KEY(a));
@@ -3608,7 +3608,7 @@ WHERE t1.id = 8 AND t2.i BETWEEN t1.b AND t1.e AND
 t3.a=t2.a AND t3.c IN ('bb','ee');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t2	range	si	si	5	NULL	4	Using index condition; Using where; Using MRR
+1	SIMPLE	t2	range	si	si	5	NULL	4	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t3	eq_ref	PRIMARY,ci	PRIMARY	4	test.t2.a	1	Using where
 EXPLAIN
 SELECT t3.a FROM t1,t2,t3
@@ -3616,7 +3616,7 @@ WHERE t1.id = 8 AND t2.i BETWEEN t1.b AND t1.e AND
 t3.a=t2.a AND t3.c IN ('bb','ee') ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t2	range	si,ai	si	5	NULL	4	Using index condition; Using where; Using MRR
+1	SIMPLE	t2	range	si,ai	si	5	NULL	4	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t3	eq_ref	PRIMARY,ci	PRIMARY	4	test.t2.a	1	Using where
 EXPLAIN 
 SELECT t3.a FROM t1,t2 FORCE INDEX (si),t3
@@ -3624,7 +3624,7 @@ WHERE t1.id = 8 AND (t2.i=t1.b OR t2.i=t1.e) AND t3.a=t2.a AND
 t3.c IN ('bb','ee');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t2	range	si	si	5	NULL	2	Using index condition; Using where; Using MRR
+1	SIMPLE	t2	range	si	si	5	NULL	2	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t3	eq_ref	PRIMARY,ci	PRIMARY	4	test.t2.a	1	Using where
 EXPLAIN 
 SELECT t3.a FROM t1,t2,t3
@@ -3632,7 +3632,7 @@ WHERE t1.id = 8 AND (t2.i=t1.b OR t2.i=t1.e) AND t3.a=t2.a AND
 t3.c IN ('bb','ee');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t2	range	si,ai	si	5	NULL	2	Using index condition; Using where; Using MRR
+1	SIMPLE	t2	range	si,ai	si	5	NULL	2	Using index condition; Using where; Rowid-ordered scan
 1	SIMPLE	t3	eq_ref	PRIMARY,ci	PRIMARY	4	test.t2.a	1	Using where
 DROP TABLE t1,t2,t3;
 CREATE TABLE t1 ( f1 int primary key, f2 int, f3 int, f4 int, f5 int, f6 int, checked_out int);
@@ -3752,7 +3752,7 @@ AND t1.ts BETWEEN t2.dt1 AND t2.dt2
 AND t1.ts BETWEEN "2006-01-01" AND "2006-12-31";
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	const	PRIMARY	PRIMARY	4	const	1	
-1	SIMPLE	t1	range	ts	ts	4	NULL	1	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	ts	ts	4	NULL	1	Using index condition; Using where; Rowid-ordered scan
 Warnings:
 Warning	1292	Incorrect datetime value: '2999-12-31 00:00:00' for column 'ts' at row 1
 SELECT * FROM t1 LEFT JOIN t2 ON (t1.a=t2.a) WHERE t1.a=30
@@ -4376,12 +4376,12 @@ CREATE TABLE t1 (a INT KEY, b INT);
 INSERT INTO t1 VALUES (1,1), (2,2), (3,3), (4,4);
 EXPLAIN EXTENDED SELECT a, b FROM t1 WHERE a > 1 AND a = b LIMIT 2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	3	100.00	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	3	100.00	Using index condition; Using where; Rowid-ordered scan
 Warnings:
 Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = `test`.`t1`.`a`) and (`test`.`t1`.`a` > 1)) limit 2
 EXPLAIN EXTENDED SELECT a, b FROM t1 WHERE a > 1 AND b = a LIMIT 2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	3	100.00	Using index condition; Using where; Using MRR
+1	SIMPLE	t1	range	PRIMARY	PRIMARY	4	NULL	3	100.00	Using index condition; Using where; Rowid-ordered scan
 Warnings:
 Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b` from `test`.`t1` where ((`test`.`t1`.`b` = `test`.`t1`.`a`) and (`test`.`t1`.`a` > 1)) limit 2
 DROP TABLE t1;

mysql-test/r/subselect3.result

@@ -1135,7 +1135,7 @@ and t4.pk=t1.c);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	
 1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t1	range	kp1	kp1	5	NULL	48	Using index condition; Using where; Using MRR
+2	SUBQUERY	t1	range	kp1	kp1	5	NULL	48	Using index condition; Using where; Rowid-ordered scan
 2	SUBQUERY	t4	eq_ref	PRIMARY	PRIMARY	4	test.t1.c	1	Using index
 drop table t1, t3, t4;
 create table t1 (a int) as select * from t0 where a < 5;

mysql-test/r/subselect3_jcl6.result

@@ -167,7 +167,7 @@ from t3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	DEPENDENT SUBQUERY	t1	ref_or_null	a	a	5	func	4	100.00	Using where; Full scan on NULL key
-2	DEPENDENT SUBQUERY	t2	ref	a	a	5	test.t1.b	1	100.00	Using where; Using join buffer (flat, BKA join)
+2	DEPENDENT SUBQUERY	t2	ref	a	a	5	test.t1.b	1	100.00	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 Warnings:
 Note	1276	Field or reference 'test.t3.oref' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<expr_cache><`test`.`t3`.`a`,`test`.`t3`.`oref`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select 1 from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond(((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`) or isnull(`test`.`t1`.`a`)))) having trigcond(<is_not_null_test>(`test`.`t1`.`a`))))) AS `Z` from `test`.`t3`
@@ -195,7 +195,7 @@ from t3;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	
 2	DEPENDENT SUBQUERY	t1	ref	a	a	4	func	2	100.00	Using where; Full scan on NULL key
-2	DEPENDENT SUBQUERY	t2	ref	a	a	4	test.t1.b	1	100.00	Using where; Using join buffer (flat, BKA join)
+2	DEPENDENT SUBQUERY	t2	ref	a	a	4	test.t1.b	1	100.00	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 Warnings:
 Note	1276	Field or reference 'test.t3.oref' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t3`.`a` AS `a`,`test`.`t3`.`oref` AS `oref`,<expr_cache><`test`.`t3`.`a`,`test`.`t3`.`oref`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select 1 from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`a` = `test`.`t1`.`b`) and (`test`.`t2`.`b` = `test`.`t3`.`oref`) and trigcond((<cache>(`test`.`t3`.`a`) = `test`.`t1`.`a`)))))) AS `Z` from `test`.`t3`
@@ -739,7 +739,7 @@ WHERE t3.name='xxx' AND t2.id=t3.id);
 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	eq_ref	PRIMARY	PRIMARY	4	func	1	Using where; Using index; Full scan on NULL key
-2	DEPENDENT SUBQUERY	t3	eq_ref	PRIMARY	PRIMARY	4	func	1	Using index condition(BKA); Using where; Full scan on NULL key; Using join buffer (flat, BKA join)
+2	DEPENDENT SUBQUERY	t3	eq_ref	PRIMARY	PRIMARY	4	func	1	Using index condition(BKA); Using where; Full scan on NULL key; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 SELECT * FROM t1
 WHERE t1.id NOT IN (SELECT t2.id FROM t2,t3 
 WHERE t3.name='xxx' AND t2.id=t3.id);
@@ -1142,7 +1142,7 @@ and t4.pk=t1.c);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	
 1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t1	range	kp1	kp1	5	NULL	48	Using index condition; Using where; Using MRR
+2	SUBQUERY	t1	range	kp1	kp1	5	NULL	48	Using index condition; Using where; Rowid-ordered scan
 2	SUBQUERY	t4	eq_ref	PRIMARY	PRIMARY	4	test.t1.c	1	Using index
 drop table t1, t3, t4;
 create table t1 (a int) as select * from t0 where a < 5;
@@ -1175,7 +1175,7 @@ insert into t3 select A.a + 10*B.a, 'filler' from t0 A, t0 B;
 explain select * from t3 where a in (select a from t2) and (a > 5 or a < 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	2	
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	Using join buffer (flat, BKA join)
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
 select * from t3 where a in (select a from t2);
 a	filler
@@ -1224,7 +1224,7 @@ explain select * from t1, t3 where t3.a in (select a from t2) and (t3.a < 10 or
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	Using join buffer (flat, BKA join)
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
 explain select straight_join * from t1 A, t1 B where A.a in (select a from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -1254,14 +1254,14 @@ explain select * from t0, t3 where t3.a in (select a from t2) and (t3.a < 10 or
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	system	NULL	NULL	NULL	NULL	1	
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	Using join buffer (flat, BKA join)
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	10	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	10	Using where
 create table t4 as select a as x, a as y from t1;
 explain select * from t0, t3 where (t3.a, t3.b) in (select x,y from t4) and (t3.a < 10 or t3.a >30);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	system	NULL	NULL	NULL	NULL	1	
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	a	a	5	test.t4.x	10	Using where; Using join buffer (flat, BKA join)
+1	PRIMARY	t3	ref	a	a	5	test.t4.x	10	Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 2	SUBQUERY	t4	ALL	NULL	NULL	NULL	NULL	10	Using where
 drop table t0,t1,t2,t3,t4;
 create table t0 (a int);
@@ -1412,7 +1412,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	2	1.00	
 1	PRIMARY	a	index	PRIMARY	PRIMARY	4	NULL	2	100.00	Using where; Using index; Using join buffer (flat, BNL join)
 2	SUBQUERY	cona	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-2	SUBQUERY	c	eq_ref	PRIMARY	PRIMARY	4	test.cona.idContact	1	100.00	Using join buffer (flat, BKA join)
+2	SUBQUERY	c	eq_ref	PRIMARY	PRIMARY	4	test.cona.idContact	1	100.00	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 Warnings:
 Note	1003	select `test`.`a`.`idIndividual` AS `idIndividual` from `test`.`t1` `a` semi join (`test`.`t3` `cona` join `test`.`t2` `c`) where ((`test`.`c`.`idContact` = `test`.`cona`.`idContact`) and (`test`.`a`.`idIndividual` = `test`.`c`.`idObj`) and (`test`.`cona`.`postalStripped` = 'T2H3B2'))
 drop table t1,t2,t3;

mysql-test/r/subselect_mat.result

@@ -1213,7 +1213,7 @@ EXPLAIN SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	Using index condition; Using MRR
+2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	Using index condition; Rowid-ordered scan
 SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 pk
 2
@@ -1363,7 +1363,7 @@ EXPLAIN SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	5	func	1	
-2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	Using index condition; Using MRR
+2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	Using index condition; Rowid-ordered scan
 SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
 pk
 2

mysql-test/r/subselect_sj.result

@@ -812,7 +812,7 @@ EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
 1	PRIMARY	subselect2	eq_ref	unique_key	unique_key	13	func	1	1.00	
-2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using MRR
+2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Rowid-ordered scan
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
@@ -821,7 +821,7 @@ pk
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, c) IN (SELECT b, c FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Using MRR; FirstMatch(t1)
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`c` = `test`.`t1`.`c`) and (`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (b, c) IN (SELECT b, c FROM t2 WHERE pk > 0);
@@ -831,7 +831,7 @@ pk
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, d) IN (SELECT b, d FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Using MRR; FirstMatch(t1)
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`d` = `test`.`t1`.`d`) and (`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (b, d) IN (SELECT b, d FROM t2 WHERE pk > 0);
@@ -840,7 +840,7 @@ pk
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, e) IN (SELECT b, e FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Using MRR; FirstMatch(t1)
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`e` = `test`.`t1`.`e`) and (`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (b, e) IN (SELECT b, e FROM t2 WHERE pk > 0);
@@ -850,7 +850,7 @@ pk
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, f) IN (SELECT b, f FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Using MRR; FirstMatch(t1)
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`f` = `test`.`t1`.`f`) and (`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (b, f) IN (SELECT b, f FROM t2 WHERE pk > 0);
@@ -860,7 +860,7 @@ pk
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, g) IN (SELECT b, g FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Using MRR; FirstMatch(t1)
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`g` = `test`.`t1`.`g`) and (`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (b, g) IN (SELECT b, g FROM t2 WHERE pk > 0);
@@ -870,7 +870,7 @@ pk
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, h) IN (SELECT b, h FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Using MRR; FirstMatch(t1)
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`h` = `test`.`t1`.`h`) and (`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (b, h) IN (SELECT b, h FROM t2 WHERE pk > 0);
@@ -880,7 +880,7 @@ pk
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, i) IN (SELECT b, i FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Using MRR; FirstMatch(t1)
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`i` = `test`.`t1`.`i`) and (`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (b, i) IN (SELECT b, i FROM t2 WHERE pk > 0);
@@ -890,7 +890,7 @@ pk
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, j) IN (SELECT b, j FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Using MRR; FirstMatch(t1)
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`j` = `test`.`t1`.`j`) and (`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (b, j) IN (SELECT b, j FROM t2 WHERE pk > 0);
@@ -900,7 +900,7 @@ pk
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (b, k) IN (SELECT b, k FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Using MRR; FirstMatch(t1)
+1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
 Warnings:
 Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`k` = `test`.`t1`.`k`) and (`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (b, k) IN (SELECT b, k FROM t2 WHERE pk > 0);

mysql-test/r/subselect_sj2.result

@@ -311,7 +311,7 @@ t2.Code IN (SELECT Country FROM t3
 WHERE Language='English' AND Percentage > 10 AND
 t2.Population > 100000);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	range	Population,Country	Population	4	NULL	1	Using index condition; Using MRR
+1	PRIMARY	t1	range	Population,Country	Population	4	NULL	1	Using index condition; Rowid-ordered scan
 1	PRIMARY	t3	eq_ref	PRIMARY,Percentage	PRIMARY	33	test.t1.Country,const	1	Using index condition; Using where
 1	PRIMARY	t2	eq_ref	PRIMARY,Population	PRIMARY	3	test.t1.Country	1	Using where
 DROP TABLE t1,t2,t3;

mysql-test/r/subselect_sj2_jcl6.result

@@ -40,7 +40,7 @@ a	b
 explain select * from t2 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	3	
-1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	Using join buffer (flat, BKA join)
+1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
 select * from t2 where b in (select a from t1);
 a	b
@@ -83,7 +83,7 @@ from t0 A, t0 B where B.a <5;
 explain select * from t3 where b in (select a from t0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	subselect2	ALL	unique_key	NULL	NULL	NULL	10	
-1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	Using join buffer (flat, BKA join)
+1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
 2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where
 set @save_ecp= @@engine_condition_pushdown;
 set engine_condition_pushdown=0;
@@ -318,9 +318,9 @@ t2.Code IN (SELECT Country FROM t3
 WHERE Language='English' AND Percentage > 10 AND
 t2.Population > 100000);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	range	Population,Country	Population	4	NULL	1	Using index condition; Using MRR
-1	PRIMARY	t3	eq_ref	PRIMARY,Percentage	PRIMARY	33	test.t1.Country,const	1	Using index condition; Using where; Using join buffer (flat, BKA join)
-1	PRIMARY	t2	eq_ref	PRIMARY,Population	PRIMARY	3	test.t1.Country	1	Using where; Using join buffer (incremental, BKA join)
+1	PRIMARY	t1	range	Population,Country	Population	4	NULL	1	Using index condition; Rowid-ordered scan
+1	PRIMARY	t3	eq_ref	PRIMARY,Percentage	PRIMARY	33	test.t1.Country,const	1	Using index condition; Using where; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	t2	eq_ref	PRIMARY,Population	PRIMARY	3	test.t1.Country	1	Using where; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
 DROP TABLE t1,t2,t3;
 CREATE TABLE t1 (
 Code char(3) NOT NULL DEFAULT '',
@@ -434,8 +434,8 @@ where t0.a in ( select t1.a from t1,t2 where t2.a=t0.a and
 t1.b=t2.b);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where; Start temporary
-1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Using join buffer (flat, BKA join)
-1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	100.00	Using where; End temporary; Using join buffer (incremental, BKA join)
+1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	100.00	Using where; End temporary; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
 Warnings:
 Note	1276	Field or reference 'test.t0.a' of SELECT #2 was resolved in SELECT #1
 Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where ((`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t1`.`a` = `test`.`t0`.`a`) and (`test`.`t2`.`a` = `test`.`t0`.`a`))

mysql-test/r/table_elim.result

@@ -128,7 +128,7 @@ Note	1003	select `f`.`id` AS `id` from `test`.`t0` `f` where (`f`.`id` in (1,2,3
 This should use facts and a1 tables:
 explain extended select id from v1 where attr1 between 12 and 14;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	a1	range	PRIMARY,attr1	attr1	5	NULL	2	100.00	Using index condition; Using MRR
+1	PRIMARY	a1	range	PRIMARY,attr1	attr1	5	NULL	2	100.00	Using index condition; Rowid-ordered scan
 1	PRIMARY	f	eq_ref	PRIMARY	PRIMARY	4	test.a1.id	1	100.00	Using index
 Warnings:
 Note	1276	Field or reference 'test.a2.id' of SELECT #3 was resolved in SELECT #1
@@ -136,7 +136,7 @@ Note	1003	select `f`.`id` AS `id` from `test`.`t0` `f` join `test`.`t1` `a1` whe
 This should use facts, a2 and its subquery:
 explain extended select id from v1 where attr2 between 12 and 14;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	a2	range	PRIMARY,attr2	attr2	5	NULL	5	100.00	Using index condition; Using where; Using MRR
+1	PRIMARY	a2	range	PRIMARY,attr2	attr2	5	NULL	5	100.00	Using index condition; Using where; Rowid-ordered scan
 1	PRIMARY	f	eq_ref	PRIMARY	PRIMARY	4	test.a2.id	1	100.00	Using index
 3	DEPENDENT SUBQUERY	t2	ref	PRIMARY	PRIMARY	4	test.a2.id	2	100.00	Using index
 Warnings:
@@ -156,7 +156,7 @@ Note	1003	select `f`.`id` AS `id` from `test`.`t0` `f` where (`f`.`id` in (1,2,3
 This should use facts and a1 tables:
 explain extended select id from v2 where attr1 between 12 and 14;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	a1	range	PRIMARY,attr1	attr1	5	NULL	2	100.00	Using index condition; Using MRR
+1	PRIMARY	a1	range	PRIMARY,attr1	attr1	5	NULL	2	100.00	Using index condition; Rowid-ordered scan
 1	PRIMARY	f	eq_ref	PRIMARY	PRIMARY	4	test.a1.id	1	100.00	Using index
 Warnings:
 Note	1276	Field or reference 'test.f.id' of SELECT #3 was resolved in SELECT #1
@@ -164,7 +164,7 @@ Note	1003	select `f`.`id` AS `id` from `test`.`t0` `f` join `test`.`t1` `a1` whe
 This should use facts, a2 and its subquery:
 explain extended select id from v2 where attr2 between 12 and 14;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	a2	range	PRIMARY,attr2	attr2	5	NULL	5	100.00	Using index condition; Using MRR
+1	PRIMARY	a2	range	PRIMARY,attr2	attr2	5	NULL	5	100.00	Using index condition; Rowid-ordered scan
 1	PRIMARY	f	eq_ref	PRIMARY	PRIMARY	4	test.a2.id	1	100.00	Using where; Using index
 3	DEPENDENT SUBQUERY	t2	ref	PRIMARY	PRIMARY	4	test.f.id	2	100.00	Using index
 Warnings:
@@ -416,7 +416,7 @@ select t1.*
 from t1 left join t2 on (t2.pk=3 and t2.b=3) or (t2.pk= 4 and t2.b=3);
 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	range	PRIMARY	PRIMARY	4	NULL	2	Using where; Using MRR
+1	SIMPLE	t2	range	PRIMARY	PRIMARY	4	NULL	2	Using where; Rowid-ordered scan
 drop table t1, t2;
 #
 # LPBUG#523593: Running RQG optimizer_no_subquery crashes MariaDB

sql/handler.h

@@ -1358,6 +1358,15 @@ void get_sweep_read_cost(TABLE *table, ha_rows nrows, bool interrupted,
 */
 #define HA_MRR_MATERIALIZED_KEYS 256
 
+#define HA_MRR_IMPLEMENTATION_FLAG1 512
+#define HA_MRR_IMPLEMENTATION_FLAG2 1024
+#define HA_MRR_IMPLEMENTATION_FLAG3 2048
+#define HA_MRR_IMPLEMENTATION_FLAG4 4096
+#define HA_MRR_IMPLEMENTATION_FLAG5 8192
+#define HA_MRR_IMPLEMENTATION_FLAG6 16384
+
+#define HA_MRR_IMPLEMENTATION_FLAGS \
+  (512 | 1024 | 2048 | 4096 | 8192 | 16384)
 
 /*
   This is a buffer area that the handler can use to store rows.
@@ -1863,14 +1872,40 @@ public:
   virtual ha_rows multi_range_read_info_const(uint keyno, RANGE_SEQ_IF *seq,
                                               void *seq_init_param, 
                                               uint n_ranges, uint *bufsz,
-                                              uint *flags, COST_VECT *cost);
+                                              uint *mrr_mode, COST_VECT *cost);
   virtual ha_rows multi_range_read_info(uint keyno, uint n_ranges, uint keys,
                                         uint key_parts, uint *bufsz, 
-                                        uint *flags, COST_VECT *cost);
+                                        uint *mrr_mode, COST_VECT *cost);
   virtual int multi_range_read_init(RANGE_SEQ_IF *seq, void *seq_init_param,
-                                    uint n_ranges, uint mode, 
+                                    uint n_ranges, uint mrr_mode, 
                                     HANDLER_BUFFER *buf);
   virtual int multi_range_read_next(range_id_t *range_info);
+  /*
+    Return string representation of the MRR plan.
+
+    This is intended to be used for EXPLAIN, via the following scenario:
+    1. SQL layer calls handler->multi_range_read_info().
+    1.1. Storage engine figures out whether it will use some non-default
+         MRR strategy, sets appropritate bits in *mrr_mode, and returns 
+         control to SQL layer
+    2. SQL layer remembers the returned mrr_mode
+    3. SQL layer compares various options and choses the final query plan. As
+       a part of that, it makes a choice of whether to use the MRR strategy
+       picked in 1.1
+    4. EXPLAIN code converts the query plan to its text representation. If MRR
+       strategy is part of the plan, it calls
+       multi_range_read_explain_info(mrr_mode) to get a text representation of
+       the picked MRR strategy.
+
+    @param mrr_mode   Mode which was returned by multi_range_read_info[_const]
+    @param str        INOUT string to be printed for EXPLAIN
+    @param str_end    End of the string buffer. The function is free to put the 
+                      string into [str..str_end] memory range.
+  */
+  virtual int multi_range_read_explain_info(uint mrr_mode, char *str, 
+                                            size_t size)
+  { return 0; }
+
   virtual int read_range_first(const key_range *start_key,
                                const key_range *end_key,
                                bool eq_range, bool sorted);

sql/multi_range_read.cc

@@ -1372,7 +1372,7 @@ ha_rows DsMrr_impl::dsmrr_info(uint keyno, uint n_ranges, uint rows,
   DBUG_ASSERT(!res);
 
   if ((*flags & HA_MRR_USE_DEFAULT_IMPL) || 
-      choose_mrr_impl(keyno, rows, &def_flags, &def_bufsz, cost))
+      choose_mrr_impl(keyno, rows, flags, bufsz, cost))
   {
     /* Default implementation is choosen */
     DBUG_PRINT("info", ("Default MRR implementation choosen"));
@@ -1517,11 +1517,13 @@ bool DsMrr_impl::choose_mrr_impl(uint keyno, ha_rows rows, uint *flags,
   bool doing_cpk_scan= check_cpk_scan(thd, keyno, *flags); 
   bool using_cpk= test(keyno == table->s->primary_key &&
                        primary_file->primary_key_is_clustered());
+  *flags &= ~HA_MRR_IMPLEMENTATION_FLAGS;
   if (thd->variables.optimizer_use_mrr == 2 || *flags & HA_MRR_INDEX_ONLY ||
       (using_cpk && !doing_cpk_scan) || key_uses_partial_cols(table, keyno))
   {
     /* Use the default implementation */
     *flags |= HA_MRR_USE_DEFAULT_IMPL;
+    *flags &= ~HA_MRR_IMPLEMENTATION_FLAGS;
     return TRUE;
   }
 
@@ -1549,9 +1551,24 @@ bool DsMrr_impl::choose_mrr_impl(uint keyno, ha_rows rows, uint *flags,
     *cost= dsmrr_cost;
     res= FALSE;
 
+
+    if ((using_cpk && doing_cpk_scan) ||
+        (optimizer_flag(thd, OPTIMIZER_SWITCH_MRR_SORT_KEYS) &&
+         *flags & HA_MRR_SINGLE_POINT))
+    {
+      *flags |= DSMRR_IMPL_SORT_KEYS;
+    }
+    
+    if (!(using_cpk && doing_cpk_scan) &&
+        !(*flags & HA_MRR_INDEX_ONLY))
+    {
+      *flags |= DSMRR_IMPL_SORT_ROWIDS;
+    }
+    /*
     if ((*flags & HA_MRR_SINGLE_POINT) && 
          optimizer_flag(thd, OPTIMIZER_SWITCH_MRR_SORT_KEYS))
       *flags |= HA_MRR_MATERIALIZED_KEYS;
+    */
   }
   else
   {
@@ -1561,6 +1578,38 @@ bool DsMrr_impl::choose_mrr_impl(uint keyno, ha_rows rows, uint *flags,
   return res;
 }
 
+/*
+  Take the flags we've returned previously and print one of
+  - Key-ordered scan
+  - Rowid-ordered scan
+  - Key-ordered Rowid-ordered scan
+*/
+
+int DsMrr_impl::dsmrr_explain_info(uint mrr_mode, char *str, size_t size)
+{
+  const char *key_ordered=   "Key-ordered scan";
+  const char *rowid_ordered= "Rowid-ordered scan";
+  const char *both_ordered=  "Key-ordered Rowid-ordered scan";
+  const char *used_str="";
+  const uint BOTH_FLAGS= (DSMRR_IMPL_SORT_KEYS | DSMRR_IMPL_SORT_ROWIDS);
+
+  if (!(mrr_mode & HA_MRR_USE_DEFAULT_IMPL))
+  {
+    if ((mrr_mode & BOTH_FLAGS) == BOTH_FLAGS)
+      used_str= both_ordered;
+    else if (mrr_mode & DSMRR_IMPL_SORT_KEYS)
+      used_str= key_ordered;
+    else if (mrr_mode & DSMRR_IMPL_SORT_ROWIDS)
+      used_str= rowid_ordered;
+
+    uint used_str_len= strlen(used_str);
+    uint copy_len= min(used_str_len, size);
+    memcpy(str, used_str, size);
+    return copy_len;
+  }
+  return 0;
+}
+
 
 static void get_sort_and_sweep_cost(TABLE *table, ha_rows nrows, COST_VECT *cost);
 

sql/multi_range_read.h

@@ -395,6 +395,9 @@ public:
 };
 
 
+#define DSMRR_IMPL_SORT_KEYS   HA_MRR_IMPLEMENTATION_FLAG1
+#define DSMRR_IMPL_SORT_ROWIDS HA_MRR_IMPLEMENTATION_FLAG2
+
 /*
   DS-MRR implementation for one table. Create/use one object of this class for
   each ha_{myisam/innobase/etc} object. That object will be further referred to
@@ -548,6 +551,8 @@ public:
   ha_rows dsmrr_info_const(uint keyno, RANGE_SEQ_IF *seq, 
                             void *seq_init_param, uint n_ranges, uint *bufsz,
                             uint *flags, COST_VECT *cost);
+
+  int dsmrr_explain_info(uint mrr_mode, char *str, size_t size);
 private:
   /* Buffer to store (key, range_id) pairs */
   Lifo_buffer *key_buffer;

sql/sql_join_cache.cc

@@ -2491,8 +2491,36 @@ void JOIN_CACHE::print_explain_comment(String *str)
   str->append(join_alg);
   str->append(STRING_WITH_LEN(" join"));
   str->append(STRING_WITH_LEN(")"));
- }
-   
+}
+
+
+static void add_mrr_explain_info(String *str, uint mrr_mode, handler *file)
+{
+  char mrr_str_buf[128]={0};
+  int len;
+  len= file->multi_range_read_explain_info(mrr_mode, mrr_str_buf,
+                                           sizeof(mrr_str_buf));
+  if (len > 0)
+  {
+    str->append(STRING_WITH_LEN("; "));
+    str->append(mrr_str_buf, len);
+  }
+}
+
+
+void JOIN_CACHE_BKA::print_explain_comment(String *str)
+{
+  JOIN_CACHE::print_explain_comment(str); 
+  add_mrr_explain_info(str, mrr_mode, join_tab->table->file);
+}
+
+
+void JOIN_CACHE_BKAH::print_explain_comment(String *str)
+{
+  JOIN_CACHE::print_explain_comment(str); 
+  add_mrr_explain_info(str, mrr_mode, join_tab->table->file);
+}
+
 
 /* 
   Initialize a hashed join cache       

sql/sql_join_cache.h

@@ -637,7 +637,7 @@ public:
   enum_nested_loop_state join_records(bool skip_last);
 
   /* Add a comment on the join algorithm employed by the join cache */
-  void print_explain_comment(String *str);
+  virtual void print_explain_comment(String *str);
 
   virtual ~JOIN_CACHE() {}
   void reset_join(JOIN *j) { join= j; }
@@ -1315,6 +1315,7 @@ public:
   /* Check index condition of the joined table for a record from BKA cache */
   bool skip_index_tuple(range_id_t range_info);
 
+  void print_explain_comment(String *str);
 };
 
 
@@ -1404,4 +1405,6 @@ public:
 
   /* Check index condition of the joined table for a record from BKAH cache */
   bool skip_index_tuple(range_id_t range_info);
+
+  void print_explain_comment(String *str);
 };

sql/sql_select.cc

@@ -19638,12 +19638,30 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
 	if (table->reginfo.not_exists_optimize)
 	  extra.append(STRING_WITH_LEN("; Not exists"));
 
+        /*
         if (quick_type == QUICK_SELECT_I::QS_TYPE_RANGE &&
             !(((QUICK_RANGE_SELECT*)(tab->select->quick))->mrr_flags &
              HA_MRR_USE_DEFAULT_IMPL))
         {
 	  extra.append(STRING_WITH_LEN("; Using MRR"));
         }
+        */
+        if (quick_type == QUICK_SELECT_I::QS_TYPE_RANGE)
+        {
+          char mrr_str_buf[128];
+          mrr_str_buf[0]=0;
+          int len;
+          uint mrr_flags= 
+            ((QUICK_RANGE_SELECT*)(tab->select->quick))->mrr_flags;
+          len= table->file->multi_range_read_explain_info(mrr_flags,
+                                                          mrr_str_buf,
+                                                          sizeof(mrr_str_buf));
+          if (len > 0)
+          {
+            extra.append(STRING_WITH_LEN("; "));
+            extra.append(mrr_str_buf, len);
+          }
+        }
 
 	if (need_tmp_table)
 	{

storage/maria/ha_maria.cc

@@ -3665,6 +3665,11 @@ ha_rows ha_maria::multi_range_read_info(uint keyno, uint n_ranges, uint keys,
   return ds_mrr.dsmrr_info(keyno, n_ranges, keys, key_parts, bufsz, flags, cost);
 }
 
+int ha_maria::multi_range_read_explain_info(uint mrr_mode, char *str, 
+                                            size_t size)
+{
+  return ds_mrr.dsmrr_explain_info(mrr_mode, str, size);
+}
 /* MyISAM MRR implementation ends */
 
 

storage/maria/ha_maria.h

@@ -186,6 +186,7 @@ public:
   ha_rows multi_range_read_info(uint keyno, uint n_ranges, uint keys,
                                 uint key_parts, uint *bufsz, 
                                 uint *flags, COST_VECT *cost);
+  int multi_range_read_explain_info(uint mrr_mode, char *str, size_t size);
   
   /* Index condition pushdown implementation */
   Item *idx_cond_push(uint keyno, Item* idx_cond);

storage/myisam/ha_myisam.cc

@@ -2281,6 +2281,13 @@ ha_rows ha_myisam::multi_range_read_info(uint keyno, uint n_ranges, uint keys,
   return ds_mrr.dsmrr_info(keyno, n_ranges, keys, key_parts, bufsz, flags, cost);
 }
 
+
+int ha_myisam::multi_range_read_explain_info(uint mrr_mode, char *str, 
+                                             size_t size)
+{
+  return ds_mrr.dsmrr_explain_info(mrr_mode, str, size);
+}
+
 /* MyISAM MRR implementation ends */
 
 

storage/myisam/ha_myisam.h

@@ -170,7 +170,8 @@ public:
   ha_rows multi_range_read_info(uint keyno, uint n_ranges, uint keys,
                                 uint key_parts, uint *bufsz, 
                                 uint *flags, COST_VECT *cost);
-  
+  int multi_range_read_explain_info(uint mrr_mode, char *str, size_t size);
+
   /* Index condition pushdown implementation */
   Item *idx_cond_push(uint keyno, Item* idx_cond);
 private:

storage/xtradb/handler/ha_innodb.cc

@@ -12139,6 +12139,10 @@ ha_rows ha_innobase::multi_range_read_info(uint keyno, uint n_ranges, uint keys,
   return res;
 }
 
+int ha_innobase::multi_range_read_explain_info(uint mrr_mode, char *str, size_t size)
+{
+  return ds_mrr.dsmrr_explain_info(mrr_mode, str, size);
+}
 
 /* 
   A helper function used only in index_cond_func_innodb

storage/xtradb/handler/ha_innodb.h

@@ -237,6 +237,7 @@ public:
   ha_rows multi_range_read_info(uint keyno, uint n_ranges, uint keys,
                                 uint key_parts, uint *bufsz, 
                                 uint *flags, COST_VECT *cost);
+  int multi_range_read_explain_info(uint mrr_mode, char *str, size_t size);
   DsMrr_impl ds_mrr;
 
   Item *idx_cond_push(uint keyno, Item* idx_cond);