On Thu, Sep 3, 2009 at 4:16 PM, Scott Otis<scott.otis@xxxxxxxxxx> wrote: > Sorry about not responding to the whole list earlier - this is my first time posting to a mailing list. > > Would providing more information about the size and complexities of the databases help? > > I measure I/O stats with iostat - here is the command I use: > > iostat -d -x mfid0 -t 290 2 > > I tried looking at the man page for iostat but couldn't find anywhere how to determine what the stats are for sequential vs random - any help there? > > When using 'top -m io' the postgres stats collector process is constantly at 99% - 100%. > > When using 'top' the WCPU for the postgres stats collector and the autovacuum process are constantly at 20% - 21%. > > Is that normal? It seems to me that the stats collector is doing all the I/O (which would mean the stats collector is doing 46.1 megabytes /sec). > > Also, the I/O stats don't change hardly at all (except at night during backups which makes sense). They don't go up or down with user activity on the server - which makes me wonder a little bit. I have a feeling that if I just turned off Apache that the I/O stats wouldn't change. Which leads me to believe that the I/O is not query related - its stats collecting and autovacuuming related. Is that expected? > > It seems to me that the stats collector shouldn't be using that much I/O and CPU (and the autovacuum shouldn't be using that much CPU) - therefore something in my configuration must be messed up or could be changed somehow. But maybe I'm wrong - please let me know. > > I don't think my setup is necessarily slow. I just want to make it as efficient as possible and wanted to get some feedback to see if am setting things up right. I am also looking out into the future and seeing how much load I can put on this server before getting another one. If I can reduce the I/O and CPU that the stats collector and autovacuum are using without losing any functionality then I can put more load on the server. > > Again thanks for all the help. Can you post to the list all the uncommented lines from your postgresql.conf file and attach the results of "select * from pg_stat_all_tables" as an attachment? ...Robert -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
