On Sun, 8 Feb 2004, Jeroen T. Vermeulen wrote: > On Wed, Feb 04, 2004 at 10:22:16PM +0200, Heikki Linnakangas wrote: > > > There is a system view pg_prepared_xacts that gives you all transactions > > that are in prepared state waiting for COMMITPREPARED or ABORTPREPARED. > > Great to hear that you've gotten so far with this... One question: can I > check for this view to see if 2PC is supported before issuing the new > kind of commit? I'm interested in supporting 2PC even for some regular > transactions to reduce their in-doubt window, but I don't want to issue a > command at the last moment that may fail (and thereby abort) because the > backend version I'm connected to doesn't support the new command!
Yes, I suppose that would work. Though you would have to use a query that wouldn't fail in case the view doesn't exist, otherwise you end up aborting the transaction anyway. This should work: SELECT COUNT(*) FROM pg_views WHERE schemanem='pg_catalog' AND viewname ='pg_prepared_xacts' If it returns 1, you can do 2PC, if it returns 0, you have to regular commit. However, if this gets into 7.5, I guess you could just check for the version of the backend instead with "SELECT version()". - Heikki ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
