Обсуждение: pgsql: Avoid misbehavior when hash_table_bytes < bucket_size.

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pgsql: Avoid misbehavior when hash_table_bytes < bucket_size.

От
Tom Lane
Дата:
Avoid misbehavior when hash_table_bytes < bucket_size.

It's possible to reach this case when work_mem is very small and tupsize
is (relatively) very large.  In that case ExecChooseHashTableSize would
get an assertion failure, or with asserts off it'd compute nbuckets = 0,
which'd likely cause misbehavior later (I've not checked).  To fix,
clamp the number of buckets to be at least 1.

This is due to faulty conversion of old my_log2() coding in 28d936031.
Back-patch to v13, as that was.

Zhang Mingli

Discussion: https://postgr.es/m/beb64ca0-91e2-44ac-bf4a-7ea36275ec02@Spark

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/55d9cd46f65a5fc0c3bbb69d36cc9dba597a8c9c

Modified Files
--------------
src/backend/executor/nodeHash.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)