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| author | Neil Conway <neilc@samurai.com> | 2007-08-08 18:06:55 +0000 |
|---|---|---|
| committer | Neil Conway <neilc@samurai.com> | 2007-08-08 18:06:55 +0000 |
| commit | 7824c695ac3168c8d0ea622b9e4c76bc88c71362 (patch) | |
| tree | b41b8786146386b81c20abe0f5c767fcdadfc779 /src/backend/executor/nodeAgg.c | |
| parent | b58230005b881626bf133c56e1f4d218e9037d36 (diff) | |
| download | postgresql-7824c695ac3168c8d0ea622b9e4c76bc88c71362.tar.gz postgresql-7824c695ac3168c8d0ea622b9e4c76bc88c71362.zip | |
Fix a gradual memory leak in ExecReScanAgg(). Because the aggregation
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.
Diffstat (limited to 'src/backend/executor/nodeAgg.c')
| -rw-r--r-- | src/backend/executor/nodeAgg.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/src/backend/executor/nodeAgg.c b/src/backend/executor/nodeAgg.c index b18ec2fee82..82226665874 100644 --- a/src/backend/executor/nodeAgg.c +++ b/src/backend/executor/nodeAgg.c @@ -45,7 +45,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.116.2.3 2005/01/27 23:43:16 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/executor/nodeAgg.c,v 1.116.2.4 2007/08/08 18:06:55 neilc Exp $ * *------------------------------------------------------------------------- */ @@ -1509,8 +1509,14 @@ ExecReScanAgg(AggState *node, ExprContext *exprCtxt) MemSet(econtext->ecxt_aggvalues, 0, sizeof(Datum) * 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) { |