On 2013-09-27 13:57:02 -0700, Josh Berkus wrote: > Andres, Jeff, > > > >> As far as I can tell, the only downside of doing that is that, since hint > >> bits might be set later, it is possible some dirty pages will get written > >> unhinted and then re-dirtied by the hint bit setting, when more aggressive > >> setting would have only one combined dirty write instead. But that seems > >> rather hypothetical, and if it really is a problem we should probably > >> tackle it directly rather than by barring other optimizations. > > > > I am - as evidenced - too tired to think about this properly, but I > > think you might be right here. > > Any thoughts on a fix for this we could get into 9.2.5? I don't see much chance to apply anything like this in a backbranch. Changing IO patterns in a noticeable way in a minor release is just asking for trouble. Also, this really isn't going to fix the issue discussed here - this was just about the additional ProcArrayLock contention. I don't think it would change anything dramatical in your case. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
