database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-05 07:21:24 +03:00
Code Activity

Fix a gradual memory leak in ExecReScanAgg(). Because the aggregation

Browse Source 
hash table is allocated in a child context of the agg node's memory
context, MemoryContextReset() will reset but *not* delete the child
context. Since ExecReScanAgg() proceeds to build a new hash table
from scratch (in a new sub-context), this results in leaking the
header for the previous memory context. Therefore, use
MemoryContextResetAndDeleteChildren() instead.

Credit: My colleague Sailesh Krishnamurthy at Truviso for isolating
the cause of the leak.
This commit is contained in:
Neil Conway
2007-08-08 18:07:03 +00:00
parent f614a2b508
commit 7dd8d4673f
1 changed files with 9 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
src/backend/executor/nodeAgg.c
View File

@ -61,7 +61,7 @@
* Portions Copyright (c) 1994, Regents of the University of California * Portions Copyright (c) 1994, Regents of the University of California
* *
* IDENTIFICATION * IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/nodeAgg.c,v 1.146.2.1 2007/02/02 00:07:28 tgl Exp $ * $PostgreSQL: pgsql/src/backend/executor/nodeAgg.c,v 1.146.2.2 2007/08/08 18:07:03 neilc Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -1641,8 +1641,14 @@ ExecReScanAgg(AggState *node, ExprContext *exprCtxt)
MemSet(econtext->ecxt_aggvalues, 0, sizeof(Datum) * node->numaggs); MemSet(econtext->ecxt_aggvalues, 0, sizeof(Datum) * node->numaggs);
MemSet(econtext->ecxt_aggnulls, 0, sizeof(bool) * node->numaggs); MemSet(econtext->ecxt_aggnulls, 0, sizeof(bool) * node->numaggs);
/* Release all temp storage */ /*
MemoryContextReset(node->aggcontext); * Release all temp storage. Note that with AGG_HASHED, the hash table
* is allocated in a sub-context of the aggcontext. We're going to
* rebuild the hash table from scratch, so we need to use
* MemoryContextResetAndDeleteChildren() to avoid leaking the old hash
* table's memory context header.
*/
MemoryContextResetAndDeleteChildren(node->aggcontext);
if (((Agg *) node->ss.ps.plan)->aggstrategy == AGG_HASHED) if (((Agg *) node->ss.ps.plan)->aggstrategy == AGG_HASHED)
{ {