Skip site navigation (1) Skip section navigation (2)

checkpoint segments

From: "David Parker" <dparker(at)tazznetworks(dot)com>
To: <pgsql-performance(at)postgresql(dot)org>
Subject: checkpoint segments
Date: 2005-05-16 00:22:13
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-performance
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 - all the clients picked up again and went on their way.
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. 
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
known to be a big hit in general, and if I should strive to tune so that
it never happens (if that's possible)?

David Parker    Tazz Networks    (401) 709-5130



pgsql-performance by date

Next:From: Matthew T. O'ConnorDate: 2005-05-16 02:26:50
Subject: Re: PostgreSQL strugling during high load
Previous:From: Grega BremecDate: 2005-05-15 21:57:27
Subject: Re: Swapping and Kernel 2.6

Privacy Policy | About PostgreSQL
Copyright © 1996-2018 The PostgreSQL Global Development Group