Florian Pflug <f...@phlo.org> wrote: > The serialization error, however, disappears if the two > transactions are swapped. The following sequence of commands > succeeds, even though the FK constraint is not satisfied. > > C1: BEGIN > C1: INSERT INTO child (parent_id) VALUES (0) > C2: BEGIN > C2: SET TRANSACTION ISOLATION LEVEL SERIALIZABLE > C2: SELECT TRUE -- Take snapshot *before* C1 commits > C1: COMMIT > C2: DELETE FROM parent WHERE parent_id = 0 -- Works! > C2: COMMIT Thanks for another good example. Added to serializable test suite. C2> DELETE FROM parent WHERE parent_id = 0; ERROR: could not serialize access due to read/write dependencies among transactions HINT: The transaction might succeed if retried. CONTEXT: SQL statement "SELECT TRUE FROM child WHERE parent_id = OLD.parent_id" PL/pgSQL function "ri_parent" line 2 at PERFORM By the way, when adding these, I'm taking off the "FOR SHARE" or "FOR UPDATE" clauses; they're not needed with true serializable transactions. Otherwise, examples used as presented. -Kevin
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