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. Andres -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
