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| author | Neil Conway <neilc@samurai.com> | 2007-08-08 18:07:02 +0000 |
|---|---|---|
| committer | Neil Conway <neilc@samurai.com> | 2007-08-08 18:07:02 +0000 |
| commit | 1de589bfcb6c2bbf9772b1f095909698f578056c (patch) | |
| tree | ecf8693b6a345f8f0fb8eeecf0a2f4ce07888a3f | |
| parent | 6d1607dc3f83d1de9b4daeba2f0622e29cafc524 (diff) | |
| download | postgresql-1de589bfcb6c2bbf9772b1f095909698f578056c.tar.gz postgresql-1de589bfcb6c2bbf9772b1f095909698f578056c.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.
| -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 c5c9aed7e78..8fab15a5aa1 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 1.135.2.2 2007/02/02 00:07:44 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/executor/nodeAgg.c,v 1.135.2.3 2007/08/08 18:07:02 neilc Exp $ * *------------------------------------------------------------------------- */ @@ -1498,8 +1498,14 @@ 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) { |