Hi!
When I tested simple query as following, backend process used much memory
and not freed until the backend was finished.
# This is reproduced on PostgreSQL8.3 (PostgreSQL8.3.6 - PostgreSQL8.3.12)
-------
BEGIN;
SAVEPOINT sp0;
INSERT INTO tbl VALUES (1);
RELEASE sp0;
SAVEPOINT sp1;
INSERT INTO tbl VALUES (1);
RELEASE sp1;
(repeats 10k)
ROLLBACK;
SELECT pg_sleep(10000);
-------
I think this caused by following fix.
http://archives.postgresql.org/pgsql-committers/2008-12/msg00100.php
http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/tcop/postgres.c?r1=1.560&r2=1.561)
Should "CopySnapshot()" be performed in MessageContext ?
Attached simple pathch to solve it...
Best regards,
--
NTT OSS Center
Tatsuhito Kasahara
kasahara.tatsuh...@oss.ntt.co.jp
diff -rcN postgresql-8.3.12/src/backend/tcop/postgres.c
postgresql-8.3.12_dev/src/backend/tcop/postgres.c
*** postgresql-8.3.12/src/backend/tcop/postgres.c 2010-10-01
22:36:12.000000000 +0900
--- postgresql-8.3.12_dev/src/backend/tcop/postgres.c 2010-12-16
15:46:43.000000000 +0900
***************
*** 914,919 ****
--- 914,921 ----
/*
* Set up a snapshot if parse analysis/planning will need one.
*/
+ oldcontext = MemoryContextSwitchTo(MessageContext);
+
if (analyze_requires_snapshot(parsetree))
{
mySnapshot = CopySnapshot(GetTransactionSnapshot());
***************
*** 926,932 ****
* Switch to appropriate context for constructing querytrees
(again,
* these must outlive the execution context).
*/
- oldcontext = MemoryContextSwitchTo(MessageContext);
querytree_list = pg_analyze_and_rewrite(parsetree, query_string,
NULL, 0);
--- 928,933 ----
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