It is just a simple idea syntax, not the exact one. Anyway, I am wonder how to get the 2^31 transaction IDs to cause the failure But I get the wraparound error warning when I delete a large no. of rows. So the wraparound failure is due to what reason, that I still have no idea (at least not the transaction limit, I guess) -- View this message in context: http://postgresql.1045698.n5.nabble.com/count-on-transaction-ID-tp5550894p5558198.html Sent from the PostgreSQL - performance mailing list archive at Nabble.com. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance