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.

1 files changed, 5 insertions, 5 deletions

diff --git a/mysql-test/r/table_elim.result b/mysql-test/r/table_elim.result
index 06135e28efb..5c39abfc483 100644
--- a/mysql-test/r/table_elim.result
+++ b/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