database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00
Code Activity

Bug#52357: Assertion failed: join->best_read in

Browse Source 
greedy_search optimizer_search_depth=0

The algorithm inside restore_prev_nj_state failed to
properly update the counters within the NESTED_JOIN
tree. The counter was decremented each time a table in the
node was removed from the QEP, the correct thing to do being
only to decrement it when the last table in the child node
was removed from the plan. This lead to node counters
getting negative values and the plan thus appeared
impossible. An assertion caught this.

Fixed by not recursing up the tree unless the last table in
the join nest node is removed from the plan
This commit is contained in:
Martin Hansson
2010-05-06 10:45:00 +02:00
parent f63608ea97
commit 1eada91053
4 changed files with 113 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
mysql-test/r/join_outer.result
View File

@ -1254,3 +1254,33 @@ SELECT * FROM t1 LEFT JOIN t2 ON e<>0 WHERE c=1 AND d<=>NULL;
c e d
1 0 NULL
DROP TABLE t1,t2;
#
# Bug#52357: Assertion failed: join->best_read in greedy_search
# optimizer_search_depth=0
#
CREATE TABLE t1( a INT );
INSERT INTO t1 VALUES (1),(2);
SET optimizer_search_depth = 0;
# Should not core dump on query preparation
EXPLAIN
SELECT 1
FROM t1 tt3 LEFT OUTER JOIN t1 tt4 ON 1
LEFT OUTER JOIN t1 tt5 ON 1
LEFT OUTER JOIN t1 tt6 ON 1
LEFT OUTER JOIN t1 tt7 ON 1
LEFT OUTER JOIN t1 tt8 ON 1
RIGHT OUTER JOIN t1 tt2 ON 1
RIGHT OUTER JOIN t1 tt1 ON 1
STRAIGHT_JOIN t1 tt9 ON 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE tt1 ALL NULL NULL NULL NULL 2
1 SIMPLE tt2 ALL NULL NULL NULL NULL 2
1 SIMPLE tt3 ALL NULL NULL NULL NULL 2
1 SIMPLE tt4 ALL NULL NULL NULL NULL 2
1 SIMPLE tt5 ALL NULL NULL NULL NULL 2
1 SIMPLE tt6 ALL NULL NULL NULL NULL 2
1 SIMPLE tt7 ALL NULL NULL NULL NULL 2
1 SIMPLE tt8 ALL NULL NULL NULL NULL 2
1 SIMPLE tt9 ALL NULL NULL NULL NULL 2
SET optimizer_search_depth = DEFAULT;
DROP TABLE t1;