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Fix for LP BUG#714808 and LP BUG#719280.

Browse source 
The patch also adjusts several instable test results
to order the result.

Analysis:

The function prev_record_reads() may skip (jump over)
some query plan nodes where record_count < 1. At the
same time, even though get_partial_join_cost() uses
all first N plan nodes after the last constant table,
it may produce a smaller record_count than
prev_record_reads(), because the record count for
some plan nodes may be < 1, and these nodes may not
participate in prev_record_reads.

Solution:
The current solution is to treat the result of
get_partial_join_cost() as the upper bound for the
total number of unique lookup keys.
This commit is contained in:
unknown 2011-02-15 22:17:18 +02:00
parent 6c45d903f0
commit 96efe1cab3
5 changed files with 47 additions and 13 deletions
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15
mysql-test/r/subselect_mat_cost.result
View file

@ -3985,3 +3985,18 @@ ORDER BY field1;
field1
28
drop table t1,t2;
#
# LP BUG#601124 Bug in eliminate_item_equal
# leads to crash in Item_func::Item_func
CREATE TABLE t1 ( f1 int(11), f3 varchar(1)) ;
INSERT INTO t1 VALUES (5,'m'),(NULL,'c');
CREATE TABLE t2 ( f2 int(11), f3 varchar(1)) ;
INSERT INTO t2 VALUES (6,'f'),(2,'d');
CREATE TABLE t3 ( f2 int(11), f3 varchar(1)) ;
INSERT INTO t3 VALUES (6,'f'),(2,'d');
SELECT * FROM t3
WHERE ( f2 ) IN (SELECT t1.f1
FROM t1 STRAIGHT_JOIN t2 ON t2.f3 = t1.f3
WHERE t2.f3 = 'c');
f2 f3
drop table t1,t2,t3;

4
mysql-test/suite/pbxt/r/subselect.result
View file

@ -3112,8 +3112,8 @@ ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 2),
(SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
a
1
3
2
3
4
SELECT a FROM t1
ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 1),
@ -3124,8 +3124,8 @@ ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 4),
(SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
a
1
3
2
3
4
SELECT a FROM t1
ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 4),

8
mysql-test/suite/pbxt/t/subselect.test
View file

@ -2052,7 +2052,7 @@ SELECT b, MAX(c) FROM t2 GROUP BY b, (SELECT c FROM t2 WHERE b > 2);
--error 1242
SELECT b, MAX(c) FROM t2 GROUP BY b, (SELECT c FROM t2 WHERE b > 1);
--sorted_result
SELECT a FROM t1 GROUP BY a
HAVING IFNULL((SELECT b FROM t2 WHERE b > 2),
(SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b)) > 3;
@ -2060,7 +2060,7 @@ SELECT a FROM t1 GROUP BY a
SELECT a FROM t1 GROUP BY a
HAVING IFNULL((SELECT b FROM t2 WHERE b > 1),
(SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b)) > 3;
--sorted_result
SELECT a FROM t1 GROUP BY a
HAVING IFNULL((SELECT b FROM t2 WHERE b > 4),
(SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b)) > 3;
@ -2068,7 +2068,7 @@ SELECT a FROM t1 GROUP BY a
SELECT a FROM t1 GROUP BY a
HAVING IFNULL((SELECT b FROM t2 WHERE b > 4),
(SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b)) > 3;
--sorted_result
SELECT a FROM t1
ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 2),
(SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));
@ -2076,7 +2076,7 @@ SELECT a FROM t1
SELECT a FROM t1
ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 1),
(SELECT c FROM t2 WHERE c=a AND b > 1 ORDER BY b));
--sorted_result
SELECT a FROM t1
ORDER BY IFNULL((SELECT b FROM t2 WHERE b > 4),
(SELECT c FROM t2 WHERE c=a AND b > 2 ORDER BY b));

21
mysql-test/t/subselect_mat_cost.test
View file

@ -366,7 +366,7 @@ EXPLAIN SELECT f2 FROM t3 WHERE (
)
) IS NULL ;
drop table t1, t2;
drop table t1, t2, t3;
--echo #
--echo # LP BUG#715034 Item_sum_distinct::clear(): Assertion `tree != 0' failed
@ -437,3 +437,22 @@ WHERE (SELECT t1.f1
ORDER BY field1;
drop table t1,t2;
--echo #
--echo # LP BUG#601124 Bug in eliminate_item_equal
--echo # leads to crash in Item_func::Item_func
CREATE TABLE t1 ( f1 int(11), f3 varchar(1)) ;
INSERT INTO t1 VALUES (5,'m'),(NULL,'c');
CREATE TABLE t2 ( f2 int(11), f3 varchar(1)) ;
INSERT INTO t2 VALUES (6,'f'),(2,'d');
CREATE TABLE t3 ( f2 int(11), f3 varchar(1)) ;
INSERT INTO t3 VALUES (6,'f'),(2,'d');
SELECT * FROM t3
WHERE ( f2 ) IN (SELECT t1.f1
FROM t1 STRAIGHT_JOIN t2 ON t2.f3 = t1.f3
WHERE t2.f3 = 'c');
drop table t1,t2,t3;

12
sql/opt_subselect.cc
View file

@ -3738,13 +3738,13 @@ bool JOIN::choose_subquery_plan(table_map join_tables)
outer_lookup_keys=1;
}
/*
Due to imprecise cost calculations, record/key counts my be < 1, while
an IN predicate will be executed at least once.
There cannot be more lookup keys than the total number of records.
TODO: this a temporary solution until we find a better way to compute
get_partial_join_cost() and prev_record_reads() in a consitent manner,
where it is guaranteed that (outer_lookup_keys <= outer_record_count).
*/
set_if_bigger(outer_record_count, 1);
set_if_bigger(outer_lookup_keys, 1);
DBUG_ASSERT(outer_lookup_keys <= outer_record_count);
if (outer_lookup_keys > outer_record_count)
outer_lookup_keys= outer_record_count;
/*
B. Estimate the cost and number of records of the subquery both