On Tue, Sep 3, 2013 at 10:09 PM, Satoshi Nagayasu <sn...@uptime.jp> wrote: > Hi, > > > (2013/09/04 13:07), Alvaro Herrera wrote: >> >> Satoshi Nagayasu wrote: >> >>> As you may know, this file could be handreds of MB in size, because >>> pgstat.stat holds all access statistics in each database, and it needs >>> to read/write an entire pgstat.stat frequently. >>> >>> As a result, pgstat.stat often generates massive I/O operation, >>> particularly when having a large number of tables in the database. >> >> >> We already changed it: > >> >> commit 187492b6c2e8cafc5b39063ca3b67846e8155d24 >> Author: Alvaro Herrera <alvhe...@alvh.no-ip.org> >> Date: Mon Feb 18 17:56:08 2013 -0300 >> >> Split pgstat file in smaller pieces > > Thanks for the comments. I forgot to mention that. > > Yes, we have already split single pgstat.stat file into > several pieces. > > However, we still need to read/write large amount of statistics > data when we have a large number of tables in single database > or multiple databases being accessed. Right?
Do you have a test case for measuring this? I vaguely remember from when I was testing the split patch, that I thought that after that improvement the load that was left was so low that there was little point in optimizing it further. Cheers, Jeff -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
