Simon Riggs <simon@2ndquadrant.com> writes: > This command will place a ShareLock (only) on the table, preventing > anybody from writing to the table while we freeze it. The ShareLock is > incompatible with any transaction that has written to the table, so when > we acquire the lock all writers to the table will have completed. We > then run the equivalent of a VACUUM FREEZE which will then be able to > freeze *all* rows in one pass (rather than all except the most > recent). This breaks MVCC. The fact that a transaction has completed is not license to discard tuple xmin immediately. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster