Florian Weimer <[EMAIL PROTECTED]> writes: > Is this a bug, or is SQLxx serializability defined in different terms?
Strictly speaking, we do not guarantee serializability because we do not do predicate locking. See for example http://archives.postgresql.org/pgsql-general/2003-01/msg01581.php AFAIK, no commercial database does predicate locking either, so we all fall short of true serializability. The usual solution if you need the sort of behavior you're talking about is to take a non-sharable write lock on the table you want to modify, so that only one transaction can do the COUNT/INSERT at a time. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 9: the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
