Be sure to rewind the tuplestore read pointer in non-leader CTEScan nodes. ExecInitCteScan supposed that it didn't have to do anything to the extra tuplestore read pointer it gets from tuplestore_alloc_read_pointer. However, it needs this read pointer to be positioned at the start of the tuplestore, while tuplestore_alloc_read_pointer is actually defined as cloning the current position of read pointer 0. In normal situations that accidentally works because we initialize the whole plan tree at once, before anything gets read. But it fails in an EvalPlanQual recheck, as illustrated in bug #14328 from Dima Pavlov. To fix, just forcibly rewind the pointer after tuplestore_alloc_read_pointer. The cost of doing so is negligible unless the tuplestore is already in TSS_READFILE state, which wouldn't happen in normal cases. We could consider altering tuplestore's API to make that case cheaper, but that would make for a more invasive back-patch and it doesn't seem worth it.
This has been broken probably for as long as we've had CTEs, so back-patch to all supported branches. Discussion: <32468.1474548...@sss.pgh.pa.us> Branch ------ REL9_1_STABLE Details ------- http://git.postgresql.org/pg/commitdiff/0183df5dc000fccf121c1a54504044578e43ec8e Modified Files -------------- src/backend/executor/nodeCtescan.c | 4 ++++ 1 file changed, 4 insertions(+) -- Sent via pgsql-committers mailing list (pgsql-committers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-committers