If ppl think its worth it I'll create a ticket On Sat, Dec 12, 2009 at 6:09 AM, Hannu Krosing <ha...@2ndquadrant.com>wrote:
> On Sat, 2009-12-12 at 01:19 +0100, Andres Freund wrote: > > Hi, > > > > On Saturday 12 December 2009 00:59:13 Scott Marlowe wrote: > > > On Fri, Dec 11, 2009 at 3:52 PM, Michael Clemmons > > > > Createdb takes > > > > 12secs on my system(9.10 pg8.4 and ext4) which is impossibly slow > for > > > > running 200unittests. > > > > Fsync got it to .2secs or so which is blazing but > > > > also the speed I expected being used to 8.3 and xfs. This dev box is > my > > > > laptop and the data is litterally unimportant and doesn't exist > longer > > > > than 20sec but Im all about good practices. Will definately try > > > > synchronous commit tonight once Im done working for the day. I've > got > > > > some massive copying todo later though so this will probably help in > the > > > > future as well. > > > Yeah, I'd probably resort to fsync off in that circumstance too > > > especially if syn commit off didn't help that much. > > > > How should syn commit help with creating databases? > > It does not help here. Tested ;) > > > The problem with 8.4 and creating databases is that the number of files > > increased hugely because of the introduction of relation forks. > > Plus the fact that fsync on ext4 is really slow. some info here: > > http://ldn.linuxfoundation.org/article/filesystems-data-preservation-fsync-and-benchmarks-pt-3 > > > It probably wouldnt be that hard to copy all files first, then reopen and > fsync > > them. Actually that should be a patch doable in an hour or two. > > Probably something worth doing, as it will speed this up on all > filesystems, and doubly so on ext4 and xfs. > > -- > Hannu Krosing http://www.2ndQuadrant.com > PostgreSQL Scalability and Availability > Services, Consulting and Training > > >
