FK fast-path bug repro: subxact abort silently drops pending FK checks#39
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FK fast-path bug repro: subxact abort silently drops pending FK checks#39NikolayS wants to merge 2 commits into
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Confirmed that ri_FastPathSubXactCallback() in ri_triggers.c unconditionally NULLs the fast-path cache on any subtransaction abort, discarding pending FK checks for rows that remain live in the parent transaction. This silently bypasses FK enforcement and leaves orphan rows. Tested against upstream/master (commit 84b9d6b, PostgreSQL 19devel). https://claude.ai/code/session_01RH7iZRYK8ZVnx7uMh2KUkg
Track SubTransactionId at cache creation time and only tear down the fast-path cache when the aborting subxact actually encompasses the creation point. Tested: FK violations now correctly detected, valid inserts still succeed, no resource leak warnings. https://claude.ai/code/session_01RH7iZRYK8ZVnx7uMh2KUkg
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Summary
ri_FastPathSubXactCallback()that silently bypasses FK constraint enforcementri_FastPathSubXactCallback()unconditionally NULLs the fast-path cache on any subtransaction abort, discarding buffered FK checks for rows that remain live in the parent transactionBug details
When an AFTER ROW trigger on a FK table causes an internal subtransaction abort (e.g., PL/pgSQL
BEGIN...EXCEPTION...END),ri_FastPathSubXactCallback()drops the entire fast-path cache. This discards pending FK existence checks that were buffered byri_FastPathBatchAdd()for earlier rows. The result: INSERT succeeds, orphan rows persist, and the constraint is still reported as valid.Test plan
(999, 'bad')succeeds despite no matching PK rowpg_constraint.convalidatedstill reportstrueafter the orphan is createdhttps://claude.ai/code/session_01RH7iZRYK8ZVnx7uMh2KUkg
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