Defer restoration of libraries in parallel workers.
Several users of extensions complained of crashes in parallel workers
that turned out to be due to syscache access from their _PG_init()
functions. Reorder the initialization of parallel workers so that
libraries are restored after the caches are initialized, and inside a
transaction.
This was reported in bug #15350 and elsewhere. We don't consider it
to be a bug: extensions shouldn't do that, because then they can't be
used in shared_preload_libraries. However, it's a fairly obscure
hazard and these extensions worked in practice before parallel query
came along. So let's make it work. Later commits might add a warning
message and eventually an error.
Back-patch to 9.6, where parallel query landed.
Author: Thomas Munro
Reviewed-by: Amit Kapila
Reported-by: Kieran McCusker, Jimmy
Discussion: https://postgr.es/m/153512195228.1489.8545997741965926448%40wrigleys.postgresql.org
Branch
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REL_11_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/9d178fb928040f1a5ab5b566f1ec76d7ac554587
Modified Files
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src/backend/access/transam/parallel.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)