WL#11322 SUPPORT LOOSE INDEX RANGE SCANS FOR LOW CARDINALITY.

mysql-test/include/skip_scan_data.inc

@@ -0,0 +1,43 @@
+eval CREATE TABLE t (a INT, b INT, c INT, d INT, e INT, PRIMARY KEY(a, b, c, d), KEY(b, d)) ENGINE=$engine;
+
+--disable_query_log
+CREATE TEMPORARY TABLE a (a INT);
+let $i=10;
+while ($i)
+{
+  --eval INSERT INTO a VALUES ($i)
+  dec $i;
+}
+
+CREATE TEMPORARY TABLE b (a INT);
+let $i=5;
+while ($i)
+{
+  --eval INSERT INTO b VALUES ($i)
+  dec $i;
+}
+
+CREATE TEMPORARY TABLE c (a INT);
+let $i=5;
+while ($i)
+{
+  --eval INSERT INTO c VALUES ($i)
+  dec $i;
+}
+
+CREATE TEMPORARY TABLE d (a INT);
+let $i=10;
+while ($i)
+{
+  --eval INSERT INTO d VALUES ($i)
+  dec $i;
+}
+
+INSERT INTO t SELECT a.a, b.a, c.a, d.a, d.a FROM a, b, c, d;
+
+DROP TEMPORARY TABLE a, b, c, d;
+
+--enable_query_log
+
+ANALYZE TABLE t;
+

mysql-test/include/skip_scan_query.inc

@@ -0,0 +1,41 @@
+set optimizer_switch = 'skip_scan=on';
+--eval EXPLAIN $query
+FLUSH STATUS;
+--disable_result_log
+--eval $query
+--enable_result_log
+SHOW STATUS LIKE 'handler_read%';
+--disable_query_log
+--eval CREATE TABLE skip_scan $query
+--enable_query_log
+
+set optimizer_switch = 'skip_scan=off';
+--eval EXPLAIN $query
+FLUSH STATUS;
+--disable_result_log
+--eval $query
+--enable_result_log
+SHOW STATUS LIKE 'handler_read%';
+--disable_query_log
+--eval CREATE TABLE no_skip_scan $query
+--enable_query_log
+
+--let $diff_tables= test.skip_scan, test.no_skip_scan
+--source include/diff_tables.inc
+
+--eval EXPLAIN $hint_query
+FLUSH STATUS;
+--disable_result_log
+--eval $hint_query
+--enable_result_log
+SHOW STATUS LIKE 'handler_read%';
+--disable_query_log
+--eval CREATE TABLE hint_skip_scan $hint_query
+--enable_query_log
+
+--let $diff_tables= test.hint_skip_scan, test.no_skip_scan
+--source include/diff_tables.inc
+
+--disable_query_log
+DROP TABLE skip_scan, no_skip_scan, hint_skip_scan;
+--enable_query_log

mysql-test/include/skip_scan_test.inc

@@ -0,0 +1,183 @@
+--source include/skip_scan_data.inc
+
+# These queries should do loose index scans.
+
+# Skip scan is used if 'skip_scan=on'
+--let $query= SELECT b, d FROM t WHERE d < 2
+--let $hint_query= SELECT /*+ SKIP_SCAN(t) */ b, d FROM t WHERE d < 2
+--source include/skip_scan_query.inc
+
+# Skip scan is used if 'skip_scan=on'
+--let $query = SELECT b, d FROM t WHERE d > 4
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, d FROM t WHERE d > 4
+--source include/skip_scan_query.inc
+
+# Skip scan is not used if 'skip_scan=on' due to cost
+--let $query = SELECT a, b, c, d FROM t WHERE a = 5 AND d <= 3
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a, b, c, d FROM t WHERE a = 5 AND d <= 3
+--source include/skip_scan_query.inc
+
+# Skip scan is not used if 'skip_scan=on' due to cost
+--let $query = SELECT a, b, c, d FROM t WHERE a = 5 AND d >= 98
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a, b, c, d FROM t WHERE a = 5 AND d >= 98
+--source include/skip_scan_query.inc
+
+# Skip scan is not used if 'skip_scan=on' due to cost
+--let $query = SELECT a, b, c, d FROM t WHERE a IN (1, 5) AND d >= 98
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a, b, c, d FROM t WHERE a IN (1, 5) AND d >= 98
+--source include/skip_scan_query.inc
+
+# Skip scan is not used if 'skip_scan=on' due to cost
+--let $query = SELECT a, b, c, d FROM t WHERE a IN (1, 3, 5) AND d >= 98
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a, b, c, d FROM t WHERE a IN (1, 3, 5) AND d >= 98
+--source include/skip_scan_query.inc
+
+# Skip scan is not used if 'skip_scan=on' due to cost
+--let $query = SELECT a, b, c, d FROM t WHERE a IN (1, 5) AND b IN (1, 2) AND d >= 98
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a, b, c, d FROM t WHERE a IN (1, 5) AND b IN (1, 2) AND d >= 98
+--source include/skip_scan_query.inc
+
+# Skip scan is not used if 'skip_scan=on' due to cost
+--let $query = SELECT a, b, c, d FROM t WHERE a IN (1, 2, 3, 4, 5) AND b IN (1, 2, 3) AND d >= 98
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a, b, c, d FROM t WHERE a IN (1, 2, 3, 4, 5) AND b IN (1, 2, 3) AND d >= 98
+--source include/skip_scan_query.inc
+
+# Skip scan is not used if 'skip_scan=on' due to cost
+--let $query = SELECT a, b, c, d FROM t WHERE a = 5 AND b = 2 AND d >= 98
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a, b, c, d FROM t WHERE a = 5 AND b = 2 AND d >= 98
+--source include/skip_scan_query.inc
+
+# Skip scan is used if 'skip_scan=on'
+--let $query = SELECT a+1, b, c, d FROM t WHERE a = 5 AND d < 3
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a+1, b, c, d FROM t WHERE a = 5 AND d < 3
+--source include/skip_scan_query.inc
+
+# Skip scan is not used if 'skip_scan=on' due to cost
+--let $query = SELECT b, c, d FROM t WHERE a = 5 AND d < 3
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE a = 5 AND d < 3
+--source include/skip_scan_query.inc
+
+# Skip scan is used if 'skip_scan=on'
+--let $query = SELECT a, b, c, d FROM t WHERE a = b AND d >= 98
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a, b, c, d FROM t WHERE a = b AND d >= 98
+--source include/skip_scan_query.inc
+
+# Skip scan is used if 'skip_scan=on'
+--let $query = SELECT b, c, d FROM t WHERE a = 5 AND c > 10 AND d < 3
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE a = 5 AND c > 10 AND d < 3
+--source include/skip_scan_query.inc
+
+# Skip scan is used if 'skip_scan=on'
+--let $query = SELECT b, c, d FROM t WHERE a = 5 AND c > 10 AND d < 3 ORDER BY d, c
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE a = 5 AND c > 10 AND d < 3 ORDER BY d, c
+--source include/skip_scan_query.inc
+
+# Skip scan is used if 'skip_scan=on'
+--let $query = SELECT b, c, d FROM t WHERE a = 5 AND c > 1 AND d < 3 ORDER BY d, c * -1
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE a = 5 AND c > 1 AND d < 3 ORDER BY d, c * -1
+--source include/skip_scan_query.inc
+
+# Skip scan is not used since field 'e' is not part of the index.
+--let $query = SELECT e FROM t WHERE a = 5 AND d <= 3
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ e FROM t WHERE a = 5 AND d <= 3
+--source include/skip_scan_query.inc
+
+# Skip scan is not used since field 'e' is not part of the index.
+--let $query = SELECT b, c, d FROM t WHERE a = 5 AND c > 10 AND d < 3 ORDER BY d, c, e
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE a = 5 AND c > 10 AND d < 3 ORDER BY d, c, e
+--source include/skip_scan_query.inc
+
+# Testing aggregate functions.
+--let $query = SELECT count(a), count(b), count(c)  FROM t WHERE a = 5 AND c > 10 AND d < 3
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ count(a), count(b), count(c) FROM t WHERE a = 5 AND c > 10 AND d < 3
+--source include/skip_scan_query.inc
+
+--let $query = SELECT min(a), max(b), min(c)  FROM t WHERE a = 5 AND c > 10 AND d < 3
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ min(a), max(b), min(c) FROM t WHERE a = 5 AND c > 10 AND d < 3
+--source include/skip_scan_query.inc
+
+--let $query = SELECT sum(a), sum(b), sum(c)  FROM t WHERE a = 5 AND c > 10 AND d < 3
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ sum(a), avg(b), sum(c) FROM t WHERE a = 5 AND c > 10 AND d < 3
+--source include/skip_scan_query.inc
+
+--let $query = SELECT count(*) FROM t WHERE d < 2;
+--let $hint_query = SELECT /*+ SKIP_SCAN(t) */ count(*) FROM t WHERE d < 2;
+--source include/skip_scan_query.inc
+
+if ($engine == 'innodb' )
+{
+  --echo Testing DESC index with skip scan.
+  ALTER TABLE t DROP PRIMARY KEY;
+  ALTER TABLE t DROP KEY b;
+  ALTER TABLE t ADD PRIMARY KEY(a DESC, b, c DESC, d);
+  ANALYZE TABLE t;
+
+  --let $query = SELECT b, c, d FROM t WHERE a = 5 AND c > 3 AND d < 3;
+  --let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE a = 5 AND c > 3 AND d < 3;
+  --source include/skip_scan_query.inc
+
+  --let $query = SELECT b, c, d FROM t WHERE a = 5 AND c < 3 AND d < 3;
+  --let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE a = 5 AND c < 3 AND d < 3;
+  --source include/skip_scan_query.inc
+
+  --let $query = SELECT b, c, d FROM t WHERE a = 5 AND c = 3 AND d < 3;
+  --let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE a = 5 AND c = 3 AND d < 3;
+  --source include/skip_scan_query.inc
+
+  --let $query = SELECT b, c, d FROM t WHERE a = 5 AND c BETWEEN 3 AND 5 AND d < 3;
+  --let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE a = 5 AND c BETWEEN 3 AND 5 AND d < 3;
+  --source include/skip_scan_query.inc
+
+  --let $query = SELECT b, c, d FROM t WHERE c BETWEEN 3 AND 5 AND d < 3;
+  --let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE c BETWEEN 3 AND 5 AND d < 3;
+  --source include/skip_scan_query.inc
+
+  --let $query = SELECT b, c, d FROM t WHERE d < 3;
+  --let $hint_query = SELECT /*+ SKIP_SCAN(t) */ b, c, d FROM t WHERE d < 3;
+  --source include/skip_scan_query.inc
+
+  --let $query = SELECT a, b, c, d FROM t WHERE a IN (1, 3, 5) AND d >= 5
+  --let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a, b, c, d FROM t WHERE a IN (1, 3, 5) AND d >= 5
+  --source include/skip_scan_query.inc
+
+ --let $query = SELECT a, b, c, d FROM t WHERE a IN (1, 5, 3) AND b IN (1, 2) AND d >= 5
+ --let $hint_query = SELECT /*+ SKIP_SCAN(t) */ a, b, c, d FROM t WHERE a IN (1, 5, 3) AND b in (1, 2) AND d >= 5
+ --source include/skip_scan_query.inc
+}
+
+set optimizer_switch = default;
+DROP TABLE t;
+
+if ($engine == 'innodb' )
+{
+  --echo Testing DESC index with skip scan and NULL range.
+  CREATE TABLE t1 (a INT, b INT, c INT, d INT, e INT);
+
+  INSERT INTO t1 VALUES
+  (NULL, 1, 1, 3, 4), (NULL, 2, 1, 4, 5),
+  (1, 2, 1, 3, 4), (2, 2, 1, 4, 5),
+  (5, 2, 3, 3, 4), (2, 2, 1, 4, 11),
+  (8, 2, 1, 3, 4), (7, 2, 1, 4, 9);
+
+  INSERT INTO t1 SELECT * FROM t1;
+  INSERT INTO t1 SELECT * FROM t1;
+  INSERT INTO t1 SELECT * FROM t1;
+
+  ALTER TABLE t1 ADD KEY k1(a DESC, b, c DESC, d, e DESC);
+  ANALYZE TABLE t1;
+
+  --let $query = SELECT a, b, c, d FROM t1 WHERE (a IN (1, 5) or a IS NULL) AND b in (1, 2) AND d BETWEEN 2 AND 5
+  --let $hint_query = SELECT /*+ SKIP_SCAN(t1) */ a, b, c, d FROM t1 WHERE (a IN (1, 5) or a IS NULL) AND b in (1, 2) AND d BETWEEN 2 AND 5
+  --source include/skip_scan_query.inc
+
+  ALTER TABLE t1 DROP KEY k1;
+  ALTER TABLE t1 ADD KEY k1(a, b DESC, c, d DESC, e);
+  ANALYZE TABLE t1;
+
+  --let $query = SELECT a, b, c, d FROM t1 WHERE (a IN (1, 5) or a IS NULL) AND b in (1, 2) AND d BETWEEN 2 AND 5
+  --let $hint_query = SELECT /*+ SKIP_SCAN(t1) */ a, b, c, d FROM t1 WHERE (a IN (1, 5) or a IS NULL) AND b in (1, 2) AND d BETWEEN 2 AND 5
+  --source include/skip_scan_query.inc
+
+  set optimizer_switch = default;
+  DROP TABLE t1;
+}

mysql-test/r/group_min_max.result

@@ -1532,7 +1532,7 @@ where exists ( select * from t2 where t2.c > 'b1' )
 group by a1,a2,b;
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	NULL	range	idx_t1_1,idx_t1_2	idx_t1_1	147	NULL	17	100.00	Using index for group-by
-2	SUBQUERY	t2	NULL	index	NULL	idx_t2_1	163	NULL	164	33.33	Using where; Using index
+2	SUBQUERY	t2	NULL	index	idx_t2_1	idx_t2_1	163	NULL	164	33.33	Using where; Using index
 Warnings:
 Note	1003	/* select#1 */ select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2`,`test`.`t1`.`b` AS `b`,min(`test`.`t1`.`c`) AS `min(c)`,max(`test`.`t1`.`c`) AS `max(c)` from `test`.`t1` where 1 group by `test`.`t1`.`a1`,`test`.`t1`.`a2`,`test`.`t1`.`b`
 explain select a1,a2,b,min(c),max(c) from t1 where (a1 >= 'c' or a2 < 'b') and (b > 'a') group by a1,a2,b;