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| author | Neil Conway <neilc@samurai.com> | 2007-08-08 18:07:05 +0000 |
|---|---|---|
| committer | Neil Conway <neilc@samurai.com> | 2007-08-08 18:07:05 +0000 |
| commit | c556b29a1199babc672b81065fe74fb50657c451 (patch) | |
| tree | 354a773a3fd033e60683d88086748e434fa2292a /src | |
| parent | af1022d2cd689ace5ae63136e178253cf87c688b (diff) | |
| download | postgresql-c556b29a1199babc672b81065fe74fb50657c451.tar.gz postgresql-c556b29a1199babc672b81065fe74fb50657c451.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')
| -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 d9e26d1d196..644268b6350 100644 --- a/src/backend/executor/nodeAgg.c +++ b/src/backend/executor/nodeAgg.c @@ -61,7 +61,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/executor/nodeAgg.c,v 1.152 2007/04/02 03:49:38 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeAgg.c,v 1.153 2007/08/08 18:07:05 neilc Exp $ * *------------------------------------------------------------------------- */ @@ -1646,8 +1646,14 @@ 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) { |