Guard against core dump from uninitialized subplan.
If the planner erroneously puts a non-parallel-safe SubPlan into
a parallelized portion of the query tree, nodeSubplan.c will fail
in the worker processes because it finds a null in es_subplanstates,
which it's unable to cope with. It seems worth a test-and-elog to
make that an error case rather than a core dump case.
This probably should have been included in commit 16ebab688, which
was responsible for allowing nulls to appear in es_subplanstates
to begin with. So, back-patch to v10 where that came in.
Discussion: https://postgr.es/m/924226.1604422326@sss.pgh.pa.us
Branch
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REL_10_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/9d878d7fee789d79afb846e401e56a65dd23a0f4
Modified Files
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src/backend/executor/nodeSubplan.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)