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Nimita Joshi
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Merge branch 'mysql-8.0' into mysql-trunk
2 parents 721baaf + 2010aeb commit 0934c1f

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‎mysql-test/r/myisam_explain_json_non_select_all.result

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4264,6 +4264,7 @@ EXPLAIN
42644264
"filtered": "100.00",
42654265
"index_condition": "((`test`.`t2`.`i` > 10) and (`test`.`t2`.`i` <= 18))",
42664266
"backward_index_scan": true,
4267+
"using_MRR": true,
42674268
"cost_info": {
42684269
"read_cost": "1.46",
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"eval_cost": "0.80",
@@ -5301,6 +5302,7 @@ EXPLAIN
53015302
"filtered": "100.00",
53025303
"index_condition": "((`test`.`t2`.`i` > 10) and (`test`.`t2`.`i` <= 18))",
53035304
"backward_index_scan": true,
5305+
"using_MRR": true,
53045306
"cost_info": {
53055307
"read_cost": "1.46",
53065308
"eval_cost": "0.80",

‎mysql-test/r/order_by_limit.result

Lines changed: 85 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -555,3 +555,88 @@ Warnings:
555555
Note 1003 /* select#1 */ select `test`.`test`.`a` AS `a`,`test`.`test`.`b` AS `b`,`test`.`test`.`c` AS `c`,`test`.`test`.`d` AS `d` from `test`.`test` where ((`test`.`test`.`c` = DATE'2022-06-13') and (`test`.`test`.`a` > 222)) order by `test`.`test`.`c`,`test`.`test`.`a` limit 10
556556
DROP PROCEDURE insertProc;
557557
DROP TABLE test;
558+
#
559+
# Bug#34306497 - Low limit heuristic used unnecessarily with descending scans
560+
#
561+
CREATE TABLE t1 (f1 INTEGER, f2 INTEGER, PRIMARY KEY (f1), KEY(f2, f1));
562+
INSERT INTO t1 (
563+
WITH RECURSIVE
564+
a(i) AS (SELECT 0 UNION ALL SELECT i+1 FROM a WHERE i < 9 ),
565+
b(i) AS (SELECT x.i + y.i * 10 + z.i * 100 FROM a x, a y, a z)
566+
SELECT b.i, b.i %2 FROM b ORDER BY i);
567+
ANALYZE TABLE t1;
568+
Table Op Msg_type Msg_text
569+
test.t1 analyze status OK
570+
EXPLAIN SELECT * FROM t1 WHERE f2 = 1 AND f1 <= 100 ORDER BY f1 DESC LIMIT 1;
571+
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
572+
1 SIMPLE t1 NULL range PRIMARY,f2 f2 9 NULL 50 100.00 Using where; Backward index scan; Using index
573+
Warnings:
574+
Note 1003 /* select#1 */ select `test`.`t1`.`f1` AS `f1`,`test`.`t1`.`f2` AS `f2` from `test`.`t1` where ((`test`.`t1`.`f2` = 1) and (`test`.`t1`.`f1` <= 100)) order by `test`.`t1`.`f1` desc limit 1
575+
SELECT * FROM t1 WHERE f2 = 1 AND f1 <= 100 ORDER BY f1 DESC LIMIT 1;
576+
f1 f2
577+
99 1
578+
CREATE TABLE t2 (
579+
f1 INTEGER,
580+
f2 INTEGER,
581+
f3 INTEGER,
582+
f4 INTEGER,
583+
f5 INTEGER,
584+
PRIMARY KEY (f1), KEY(f2,f3,f4,f5,f1));
585+
INSERT INTO t2 (
586+
WITH RECURSIVE a (i) AS (SELECT 0 UNION ALL SELECT i+1 FROM a WHERE i < 9 ),
587+
b (i) AS (SELECT x.i + y.i * 10 + z.i * 100 FROM a x, a y, a z)
588+
SELECT b.i, b.i%2, b.i%3, b.i%4, b.i%5 FROM b ORDER BY i);
589+
ANALYZE TABLE t2;
590+
Table Op Msg_type Msg_text
591+
test.t2 analyze status OK
592+
EXPLAIN SELECT * FROM t2
593+
WHERE f3 = 1 AND f2 = 1 AND f4 = 3 AND f5 IN(2,3) ORDER BY f4 DESC LIMIT 1;
594+
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
595+
1 SIMPLE t2 NULL range f2 f2 20 NULL 33 100.00 Using where; Backward index scan; Using index
596+
Warnings:
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Note 1003 /* select#1 */ select `test`.`t2`.`f1` AS `f1`,`test`.`t2`.`f2` AS `f2`,`test`.`t2`.`f3` AS `f3`,`test`.`t2`.`f4` AS `f4`,`test`.`t2`.`f5` AS `f5` from `test`.`t2` where ((`test`.`t2`.`f4` = 3) and (`test`.`t2`.`f2` = 1) and (`test`.`t2`.`f3` = 1) and (`test`.`t2`.`f5` in (2,3))) order by `test`.`t2`.`f4` desc limit 1
598+
SELECT * FROM t2
599+
WHERE f3 = 1 AND f2 = 1 AND f4 = 3 AND f5 IN(2,3) ORDER BY f4 DESC LIMIT 1;
600+
f1 f2 f3 f4 f5
601+
943 1 1 3 3
602+
EXPLAIN SELECT * FROM t2
603+
WHERE f2 = 1 AND f3 = 2 AND f4 = 3 AND f5 IN(2,3) ORDER BY f3,f4 DESC LIMIT 1;
604+
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
605+
1 SIMPLE t2 NULL range f2 f2 20 NULL 33 100.00 Using where; Using index
606+
Warnings:
607+
Note 1003 /* select#1 */ select `test`.`t2`.`f1` AS `f1`,`test`.`t2`.`f2` AS `f2`,`test`.`t2`.`f3` AS `f3`,`test`.`t2`.`f4` AS `f4`,`test`.`t2`.`f5` AS `f5` from `test`.`t2` where ((`test`.`t2`.`f4` = 3) and (`test`.`t2`.`f3` = 2) and (`test`.`t2`.`f2` = 1) and (`test`.`t2`.`f5` in (2,3))) order by `test`.`t2`.`f3`,`test`.`t2`.`f4` desc limit 1
608+
SELECT * FROM t2
609+
WHERE f2 = 1 AND f3 = 2 AND f4 = 3 AND f5 IN(2,3) ORDER BY f3,f4 DESC LIMIT 1;
610+
f1 f2 f3 f4 f5
611+
47 1 2 3 2
612+
EXPLAIN SELECT * FROM t2
613+
WHERE f2 = 1 AND f3 > 1 AND f4 = 3 AND f5 IN(2,3) ORDER BY f2,f3 DESC LIMIT 1;
614+
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
615+
1 SIMPLE t2 NULL range f2 f2 10 NULL 166 2.00 Using where; Backward index scan; Using index
616+
Warnings:
617+
Note 1003 /* select#1 */ select `test`.`t2`.`f1` AS `f1`,`test`.`t2`.`f2` AS `f2`,`test`.`t2`.`f3` AS `f3`,`test`.`t2`.`f4` AS `f4`,`test`.`t2`.`f5` AS `f5` from `test`.`t2` where ((`test`.`t2`.`f4` = 3) and (`test`.`t2`.`f2` = 1) and (`test`.`t2`.`f3` > 1) and (`test`.`t2`.`f5` in (2,3))) order by `test`.`t2`.`f2`,`test`.`t2`.`f3` desc limit 1
618+
SELECT * FROM t2
619+
WHERE f2 = 1 AND f3 > 1 AND f4 = 3 AND f5 IN(2,3) ORDER BY f2,f3 DESC LIMIT 1;
620+
f1 f2 f3 f4 f5
621+
983 1 2 3 3
622+
EXPLAIN SELECT * FROM t2
623+
WHERE f2 = 1 AND f3 > 1 AND f4 = 3 ORDER BY f2,f3,f5 DESC LIMIT 1;
624+
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
625+
1 SIMPLE t2 NULL range f2 f2 10 NULL 166 10.00 Using where; Using index; Using filesort
626+
Warnings:
627+
Note 1003 /* select#1 */ select `test`.`t2`.`f1` AS `f1`,`test`.`t2`.`f2` AS `f2`,`test`.`t2`.`f3` AS `f3`,`test`.`t2`.`f4` AS `f4`,`test`.`t2`.`f5` AS `f5` from `test`.`t2` where ((`test`.`t2`.`f4` = 3) and (`test`.`t2`.`f2` = 1) and (`test`.`t2`.`f3` > 1)) order by `test`.`t2`.`f2`,`test`.`t2`.`f3`,`test`.`t2`.`f5` desc limit 1
628+
SELECT * FROM t2
629+
WHERE f2 = 1 AND f3 > 1 AND f4 = 3 ORDER BY f2,f3,f5 DESC LIMIT 1;
630+
f1 f2 f3 f4 f5
631+
59 1 2 3 4
632+
EXPLAIN SELECT * FROM t2
633+
WHERE f2 = 1 AND f3 > 1 AND f4 = 3 ORDER BY f2 DESC ,f3 DESC ,f5 DESC LIMIT 1;
634+
id select_type table partitions type possible_keys key key_len ref rows filtered Extra
635+
1 SIMPLE t2 NULL range f2 f2 10 NULL 166 10.00 Using where; Backward index scan; Using index
636+
Warnings:
637+
Note 1003 /* select#1 */ select `test`.`t2`.`f1` AS `f1`,`test`.`t2`.`f2` AS `f2`,`test`.`t2`.`f3` AS `f3`,`test`.`t2`.`f4` AS `f4`,`test`.`t2`.`f5` AS `f5` from `test`.`t2` where ((`test`.`t2`.`f4` = 3) and (`test`.`t2`.`f2` = 1) and (`test`.`t2`.`f3` > 1)) order by `test`.`t2`.`f2` desc,`test`.`t2`.`f3` desc,`test`.`t2`.`f5` desc limit 1
638+
SELECT * FROM t2
639+
WHERE f2 = 1 AND f3 > 1 AND f4 = 3 ORDER BY f2 DESC ,f3 DESC ,f5 DESC LIMIT 1;
640+
f1 f2 f3 f4 f5
641+
959 1 2 3 4
642+
DROP TABLE t1,t2;

‎mysql-test/t/order_by_limit.test

Lines changed: 67 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -436,3 +436,70 @@ EXPLAIN SELECT * FROM test WHERE c = '2022-06-13' AND a > 222 ORDER BY c, a LIM
436436

437437
DROP PROCEDURE insertProc;
438438
DROP TABLE test;
439+
440+
--echo #
441+
--echo # Bug#34306497 - Low limit heuristic used unnecessarily with descending scans
442+
--echo #
443+
444+
CREATE TABLE t1 (f1 INTEGER, f2 INTEGER, PRIMARY KEY (f1), KEY(f2, f1));
445+
446+
INSERT INTO t1 (
447+
WITH RECURSIVE
448+
a(i) AS (SELECT 0 UNION ALL SELECT i+1 FROM a WHERE i < 9 ),
449+
b(i) AS (SELECT x.i + y.i * 10 + z.i * 100 FROM a x, a y, a z)
450+
SELECT b.i, b.i %2 FROM b ORDER BY i);
451+
452+
ANALYZE TABLE t1;
453+
454+
let query =
455+
SELECT * FROM t1 WHERE f2 = 1 AND f1 <= 100 ORDER BY f1 DESC LIMIT 1;
456+
457+
eval EXPLAIN $query;
458+
eval $query;
459+
460+
CREATE TABLE t2 (
461+
f1 INTEGER,
462+
f2 INTEGER,
463+
f3 INTEGER,
464+
f4 INTEGER,
465+
f5 INTEGER,
466+
PRIMARY KEY (f1), KEY(f2,f3,f4,f5,f1));
467+
468+
INSERT INTO t2 (
469+
WITH RECURSIVE a (i) AS (SELECT 0 UNION ALL SELECT i+1 FROM a WHERE i < 9 ),
470+
b (i) AS (SELECT x.i + y.i * 10 + z.i * 100 FROM a x, a y, a z)
471+
SELECT b.i, b.i%2, b.i%3, b.i%4, b.i%5 FROM b ORDER BY i);
472+
473+
ANALYZE TABLE t2;
474+
475+
let query =
476+
SELECT * FROM t2
477+
WHERE f3 = 1 AND f2 = 1 AND f4 = 3 AND f5 IN(2,3) ORDER BY f4 DESC LIMIT 1;
478+
eval EXPLAIN $query;
479+
eval $query;
480+
481+
let query =
482+
SELECT * FROM t2
483+
WHERE f2 = 1 AND f3 = 2 AND f4 = 3 AND f5 IN(2,3) ORDER BY f3,f4 DESC LIMIT 1;
484+
eval EXPLAIN $query;
485+
eval $query;
486+
487+
let query =
488+
SELECT * FROM t2
489+
WHERE f2 = 1 AND f3 > 1 AND f4 = 3 AND f5 IN(2,3) ORDER BY f2,f3 DESC LIMIT 1;
490+
eval EXPLAIN $query;
491+
eval $query;
492+
493+
let query =
494+
SELECT * FROM t2
495+
WHERE f2 = 1 AND f3 > 1 AND f4 = 3 ORDER BY f2,f3,f5 DESC LIMIT 1;
496+
eval EXPLAIN $query;
497+
eval $query;
498+
499+
let query =
500+
SELECT * FROM t2
501+
WHERE f2 = 1 AND f3 > 1 AND f4 = 3 ORDER BY f2 DESC ,f3 DESC ,f5 DESC LIMIT 1;
502+
eval EXPLAIN $query;
503+
eval $query;
504+
505+
DROP TABLE t1,t2;

‎sql/sql_optimizer.cc

Lines changed: 15 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -1825,11 +1825,13 @@ int test_if_order_by_key(ORDER_with_src *order_src, TABLE *table, uint idx,
18251825
/*
18261826
Skip key parts that are constants in the WHERE clause if these are
18271827
already removed in the ORDER expression by check_field_is_const().
1828+
If they are not removed in the ORDER expression yet, then we skip
1829+
the constant keyparts that are not part of the ORDER expression.
18281830
*/
1829-
if (order_src->is_const_optimized()) {
1830-
for (; const_key_parts & 1 && key_part < key_part_end;
1831-
const_key_parts >>= 1)
1832-
key_part++;
1831+
for (; const_key_parts & 1 && key_part < key_part_end &&
1832+
(order_src->is_const_optimized() || key_part->field != field);
1833+
const_key_parts >>= 1) {
1834+
key_part++;
18331835
}
18341836

18351837
/* Avoid usage of prefix index for sorting a partition table */
@@ -1856,11 +1858,13 @@ int test_if_order_by_key(ORDER_with_src *order_src, TABLE *table, uint idx,
18561858
/*
18571859
Skip key parts that are constants in the WHERE clause if these are
18581860
already removed in the ORDER expression by check_field_is_const().
1861+
If they are not removed in the ORDER expression yet, then we skip
1862+
the constant keyparts that are not part of the ORDER expression.
18591863
*/
1860-
if (order_src->is_const_optimized()) {
1861-
for (; const_key_parts & 1 && key_part < key_part_end;
1862-
const_key_parts >>= 1)
1863-
key_part++;
1864+
for (; const_key_parts & 1 && key_part < key_part_end &&
1865+
(order_src->is_const_optimized() || key_part->field != field);
1866+
const_key_parts >>= 1) {
1867+
key_part++;
18641868
}
18651869
/*
18661870
The primary and secondary key parts were all const (i.e. there's
@@ -9788,7 +9792,9 @@ static bool make_join_query_block(JOIN *join, Item *cond) {
97889792
*/
97899793
if (read_direction == 1 ||
97909794
(read_direction == -1 &&
9791-
is_reverse_sorted_range(tab->range_scan()))) {
9795+
reverse_sort_possible(tab->range_scan()) &&
9796+
!make_reverse(get_used_key_parts(tab->range_scan()),
9797+
tab->range_scan()))) {
97929798
recheck_reason = DONT_RECHECK;
97939799
}
97949800
}

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