From 98362d6a9c5370d00591569a70d90b49b73e4951 Mon Sep 17 00:00:00 2001 From: unknown Date: Tue, 31 Oct 2006 11:01:27 +0200 Subject: Bug #23184: SELECT causes server crash Item::val_xxx() may be called by the server several times at execute time for a single query. Calls to val_xxx() may be very expensive and sometimes (count(distinct), sum(distinct), avg(distinct)) not possible. To avoid that problem the results of calculation for these aggregate functions are cached so that val_xxx() methods just return the calculated value for the second and subsequent calls. mysql-test/r/func_group.result: Bug #23184: SELECT causes server crash - test case mysql-test/t/func_group.test: Bug #23184: SELECT causes server crash - test case sql/item_sum.cc: Bug #23184: SELECT causes server crash - caching of the aggregate function results so no need to recalculate at val_xxx() sql/item_sum.h: Bug #23184: SELECT causes server crash - caching of the aggregate function results so no need to recalculate at val_xxx() --- mysql-test/r/func_group.result | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) (limited to 'mysql-test/r/func_group.result') diff --git a/mysql-test/r/func_group.result b/mysql-test/r/func_group.result index c6117053a60..23517f7b603 100644 --- a/mysql-test/r/func_group.result +++ b/mysql-test/r/func_group.result @@ -1029,3 +1029,29 @@ t1 CREATE TABLE `t1` ( `stddev(0)` double(8,4) default NULL ) ENGINE=MyISAM DEFAULT CHARSET=latin1 drop table t1; +CREATE TABLE t1 (a INT, b INT); +INSERT INTO t1 VALUES (1,1),(1,2),(1,3),(1,4),(1,5),(1,6),(1,7),(1,8); +INSERT INTO t1 SELECT a, b+8 FROM t1; +INSERT INTO t1 SELECT a, b+16 FROM t1; +INSERT INTO t1 SELECT a, b+32 FROM t1; +INSERT INTO t1 SELECT a, b+64 FROM t1; +INSERT INTO t1 SELECT a, b+128 FROM t1; +INSERT INTO t1 SELECT a, b+256 FROM t1; +INSERT INTO t1 SELECT a, b+512 FROM t1; +INSERT INTO t1 SELECT a, b+1024 FROM t1; +INSERT INTO t1 SELECT a, b+2048 FROM t1; +INSERT INTO t1 SELECT a, b+4096 FROM t1; +INSERT INTO t1 SELECT a, b+8192 FROM t1; +INSERT INTO t1 SELECT a, b+16384 FROM t1; +INSERT INTO t1 SELECT a, b+32768 FROM t1; +SELECT a,COUNT(DISTINCT b) AS cnt FROM t1 GROUP BY a HAVING cnt > 50; +a cnt +1 65536 +SELECT a,SUM(DISTINCT b) AS sumation FROM t1 GROUP BY a HAVING sumation > 50; +a sumation +1 2147516416 +SELECT a,AVG(DISTINCT b) AS average FROM t1 GROUP BY a HAVING average > 50; +a average +1 32768.5000 +DROP TABLE t1; +End of 5.0 tests -- cgit v1.2.1