Fix possible crash with nested SubLinks. An expression such as WHERE (... x IN (SELECT ...) ...) IN (SELECT ...) could produce an invalid plan that results in a crash at execution time, if the planner attempts to flatten the outer IN into a semi-join. This happens because convert_testexpr() was not expecting any nested SubLinks and would wrongly replace any PARAM_SUBLINK Params belonging to the inner SubLink. (I think the comment denying that this case could happen was wrong when written; it's certainly been wrong for quite a long time, since very early versions of the semijoin flattening logic.)
Per report from Teodor Sigaev. Back-patch to all supported branches. Branch ------ REL8_4_STABLE Details ------- http://git.postgresql.org/pg/commitdiff/884c6384a2db34f6a65573e6bfd4b71dfba0de90 Modified Files -------------- src/backend/optimizer/plan/subselect.c | 27 ++++++++++++++++++++++----- src/test/regress/expected/subselect.out | 11 +++++++++++ src/test/regress/sql/subselect.sql | 7 +++++++ 3 files changed, 40 insertions(+), 5 deletions(-) -- Sent via pgsql-committers mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers
