Fix intra-query memory leak when a SRF returns zero rows.
When looping around after finding that the set-returning function
returned zero rows for the current input tuple, ExecProjectSet
neglected to reset either of the two memory contexts it's
responsible for cleaning out. Typically this wouldn't cause much
problem, because once the SRF does return at least one row, the
contexts would get reset on the next call. However, if the SRF
returns no rows for many input tuples in succession, quite a lot
of memory could be transiently consumed.
To fix, make sure we reset both contexts while looping around.
Per bug #18172 from Sergei Kornilov. Back-patch to all supported
branches.
Discussion: https://postgr.es/m/18172-9b8c5fc1d676ded3@postgresql.org
Branch
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REL_13_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/b7684473d74a7555e3fb7d1a492ef50d24bfce31
Modified Files
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src/backend/executor/nodeProjectSet.c | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)