On Fri, Sep 16, 2011 at 2:38 AM, Fujii Masao <masao.fu...@gmail.com> wrote: > On Fri, Sep 16, 2011 at 7:53 AM, Simon Riggs <si...@2ndquadrant.com> wrote: >> This patch splits bgwriter into 2 processes: checkpointer and >> bgwriter, seeking to avoid contentious changes. Additional changes are >> expected in this release to build upon these changes for both new >> processes, though this patch stands on its own as both a performance >> vehicle and in some ways a refcatoring to simplify the code. > > I like this idea to simplify the code. How much performance gain can we > expect by this patch?
On heavily I/O bound systems, this is likely to make a noticeable difference, since bgwriter reduces I/O in user processes. The overhead of sending signals between processes is much less than I had previously thought, so I expect no problems there, even on highly loaded systems. >> Current patch has a bug at shutdown I've not located yet, but seems >> likely is a simple error. That is mainly because for personal reasons >> I've not been able to work on the patch recently. I expect to be able >> to fix that later in the CF. > > You seem to have forgotten to include checkpointor.c and .h in the patch. I confirm this error. I'll repost full patch later in the week when I have more time. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers