Fix query-lifespan memory leakage in repeatedly executed hash joins.
ExecHashTableCreate allocated some memory that wasn't freed by
ExecHashTableDestroy, specifically the per-hash-key function information.
That's not a huge amount of data, but if one runs a query that repeats
a hash join enough times, it builds up. Fix by arranging for the data
in question to be kept in the hashtable's hashCxt instead of leaving it
"loose" in the query-lifespan executor context. (This ensures that we'll
also clean up anything that the hash functions allocate in fn_mcxt.)
Per report from Amit Khandekar. It's been like this forever, so back-patch
to all supported branches.
Discussion: https://postgr.es/m/CAJ3gD9cFofAWGvcxLOxDHC=B0hjtW8yGmUsF2hdGh97CM38=7g@mail.gmail.com
Branch
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REL9_4_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/2709549ecdd68313201307653f3ddd0f24dd8427
Modified Files
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src/backend/executor/nodeHash.c | 43 +++++++++++++++++++++--------------------
1 file changed, 22 insertions(+), 21 deletions(-)