On Fri, Jun 5, 2009 at 1:02 PM, Greg Smith<gsmith@xxxxxxxxxxxxx> wrote: > On Fri, 5 Jun 2009, Mark Mielke wrote: >> I disagree that profiling trumps theory every time. > That's an interesting theory. Unfortunately, profiling shows it doesn't > work that way. I had a laugh when I read this, but I can see someone being offended by it. Hopefully no one took it that way. > Let's see if I can summarize the state of things a bit better here: > > 1) PostgreSQL stops working as efficiently with >1000 active connections > > 2) Profiling suggests the first barrier that needs to be resolved to fix > that is how the snapshots needed to support MVCC are derived > > 3) There are multiple patches around that aim to improve that specific > situation, but only being tested aggressively by one contributor so far > (that I'm aware of) I am actually aware of only two forays into this area that have been reduced to code. I am pretty much convinced that Jignesh's wake-all-waiters patch is fundamentally - dare I say theoretically - unsound, however much it may improve performance for his particular workload. The other is Simon's patch which AIUI is a fast-path for the case where nothing has changed. Are you aware of any others? Thanks for the summary. ...Robert -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
