Peter Eisentraut wrote: > > mlw writes: > > > update mytable set foo=foo+1 where bar='xxx'; > > > > If that gets executed more than once at the same time by multiple instances of > > postgresql. Will foo ever lose a count? > > No, but if you run this in read committed isolation mode then you might > get into non-repeatable read type problems, i.e., you run it twice but > every foo was only increased once. If you use serializable mode then all > but one concurrent update will be aborted.
I'm not sure you answered my question. Let me put it to you like this: Suppose I wanted to make a table of page counts, like this: create table pagecounts (counter int4, pagename varchar) For each page hit, I do this: update pagecounts set counter = counter + 1 where pagename = 'testpag.php' Do I have to set a particular isolation level? Or does this not work in general? ---------------------------(end of broadcast)--------------------------- TIP 1: subscribe and unsubscribe commands go to [EMAIL PROTECTED]
