2010/2/2 <wyx6fox@xxxxxxxx>: > the unique constraints actualy kill concurrency write transaction when > concurrency insert violate the unique constraints , they block each other , > i test this in oracle10g, has the same behavour. I think this may be > reasonable because the uqniue check must be the seriazable check . > for resolve this problem , i do the unique check in application as possible > , but in big concurrency env , this is not good way . You may find that your way isn't actually very reliable, and that making it reliable will be very, very much harder (and likely no faster) than letting PostgreSQL do it. ...Robert -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance