Fix failure to set ActiveSnapshot while rewinding a cursor.
ActiveSnapshot needs to be set when we call ExecutorRewind because some
plan node types may execute user-defined functions during their ReScan
calls (nodeLimit.c does so, at least). The wisdom of that is somewhat
debatable, perhaps, but for now the simplest fix is to make sure the
required context is valid. Failure to do this typically led to a
null-pointer-dereference core dump, though it's possible that in more
complex cases a function could be executed with the wrong snapshot
leading to very subtle misbehavior.
Per report from Leif Jensen. It's been broken for a long time, so
back-patch to all active branches.
Branch
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REL9_2_STABLE
Details
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http://git.postgresql.org/pg/commitdiff/022b5f2b228e2d0a658b808340bd32ba904b87f4
Modified Files
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src/backend/tcop/pquery.c | 14 ++++++++++++--
src/test/regress/expected/portals.out | 24 ++++++++++++++++++++++++
src/test/regress/sql/portals.sql | 11 +++++++++++
3 files changed, 47 insertions(+), 2 deletions(-)