On Monday 28 December 2009 23:59:43 Andres Freund wrote: > On Monday 28 December 2009 23:54:51 Andres Freund wrote: > > On Saturday 12 December 2009 21:38:41 Andres Freund wrote: > > > On Saturday 12 December 2009 21:36:27 Michael Clemmons wrote: > > > > If ppl think its worth it I'll create a ticket > > > > > > Thanks, no need. I will post a patch tomorrow or so. > > > > Well. It was a long day... > > > > Anyway. > > In this patch I delay the fsync done in copy_file and simply do a second > > pass over the directory in copy_dir and fsync everything in that pass. > > Including the directory - which was not done before and actually might be > > necessary in some cases. > > I added a posix_fadvise(..., FADV_DONTNEED) to make it more likely that > > the copied file reaches storage before the fsync. Without the speed > > benefits were quite a bit smaller and essentially random (which seems > > sensible). > > > > This speeds up CREATE DATABASE from ~9 seconds to something around 0.8s > > on my laptop. Still slower than with fsync off (~0.25) but quite a > > worthy improvement. > > > > The benefits are obviously bigger if the template database includes > > anything added. > > Obviously the patch would be helpfull. And it should also be helpfull not to have annoying oversights in there. A FreeDir(xldir); is missing at the end of copydir(). Andres -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
