Hello Paul, Sunday, February 1, 2004, 10:58:25 PM, you wrote: PNT> Alexander: PNT> It sounds like a lock preventing concurrent writes would be your best PNT> bet. This would mean that only one instance of your script can be PNT> *changing* the table at one time, but it has no effect on transactions PNT> that only read from that. PNT> If I read the docs correctly: PNT> http://www.postgresql.org/docs/7.4/static/explicit-locking.html PNT> You want to obtain a ROW EXCLUSIVE lock, e.g., PNT> LOCK TABLE <table name> IN ROW EXCLUSIVE; Thanks! I am read this doc carefully. I am understand what i need: i need _any_ lock method, which conflicts along, but not conflict with ROW SHARE MODE (for working concurrent selects). I am choose IN SHARE UPDATE EXCLUSIVE MODE and test it on 3 pgsql consoles - it worked ;) Big thanks! -- Best regards, Alexander mailto:voodoo@xxxxxxxx