Re: [PERFORM] checkpoint segments

2005-05-16 Thread Josh Berkus
Alvaro, > > Yes, and yes. Simply allocating more checkpoint segments (which can eat > > a lot of disk space -- requirements are 16mb*(2 * segments +1) ) will > > prevent this problem. > > Hmm? I disagree -- it will only make things worse when the checkpoint > does occur. Unless you allocate en

Re: [PERFORM] checkpoint segments

2005-05-15 Thread Alvaro Herrera
On Sun, May 15, 2005 at 08:26:02PM -0700, Josh Berkus wrote: > David, > > > I've seen these messages in the log before, and am aware of the need to > > increase checkpoint_segments, but I wasn't aware that recycling a > > transaction log could be that damaging to performance. There may have > > be

Re: [PERFORM] checkpoint segments

2005-05-15 Thread Alvaro Herrera
On Sun, May 15, 2005 at 08:22:13PM -0400, David Parker wrote: > In the database log at that time there was a "recycling transaction log" > message which seems to correspond to the time when the clients were > paused, though I don't have it concretely correlated. Maybe what you need is make the b

Re: [PERFORM] checkpoint segments

2005-05-15 Thread Tom Lane
"David Parker" <[EMAIL PROTECTED]> writes: > I was recently running a test with multiple client shell processes > running psql commands (inserts) when all the client processes appeared > to hang simultaneously. I assumed that I had an application deadlock > somewhere, but after a few seconds - less

Re: [PERFORM] checkpoint segments

2005-05-15 Thread Josh Berkus
David, > I've seen these messages in the log before, and am aware of the need to > increase checkpoint_segments, but I wasn't aware that recycling a > transaction log could be that damaging to performance. There may have > been some local hiccup in this case, but I'm wondering if recycling is > kn

[PERFORM] checkpoint segments

2005-05-15 Thread David Parker
I was recently running a test with multiple client shell processes running psql commands (inserts) when all the client processes appeared to hang simultaneously. I assumed that I had an application deadlock somewhere, but after a few seconds - less than a minute, but certainly noticeable - a