On Fri, Apr 06, 2001 at 10:56:43AM +0200, Al wrote: > Hi all. I have a problem understanding/using PostgreSQL as a multiuser > database. > I have a simple table with a number of different IDs (int8) used for > different activities. > It should be possible for any number of simultaneous users to receive a > unique ID for a particular activity and then update these IDs. > > I thought this would be the way to go: > > --- > set transaction isolation level serializable; > > begin work; > select val from ids where cntr='ct1' for update; > update ids set val=val+(some integer value) where cntr='ct1'; > commit work; > --- > > However, when I run everything except the commit on one terminal and > then run up to and including the select on another terminal, I receive > the OLD, non-updated value for val on that second terminal. In other > words, the select is not blocked and the id is not unique. > Not what I intended at all! > > What gives? Does anybody know how to do this in PostgreSQL? SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; Note: Every other transaction will block until you do a commit or rollback -- so be quick about it... You might consider using a sequence if you can... -- Eric G. Miller <[EMAIL PROTECTED]> ---------------------------(end of broadcast)--------------------------- TIP 6: Have you searched our list archives? http://www.postgresql.org/search.mpl
