Re: Final(?) proposal for wal_sync_method changes

Josh Berkus <josh@agliodbs.com>

From: Josh Berkus <josh@agliodbs.com>
To: Greg Smith <greg@2ndquadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Magnus Hagander <magnus@hagander.net>, Bruce Momjian <bruce@momjian.us>, pgsql-hackers@postgresql.org
Date: 2010-12-10T02:47:46Z
Lists: pgsql-hackers
Greg,

> This is interesting, because test_fsync consistently reported a rate of
> about half this when using open_datasync instead of the equal
> performance I'm getting from the database.  I'll see if I can reproduce
> that further, but it's no reason to be concerned about the change that's
> been made I think.  Just more evidence that test_fsync has quirks left
> to be sorted out.  But that's not backbranch material, it should be part
> of 9.1 only refactoring, already in progress via the patch Josh
> submitted.  There's a bit of time left to get that done.

Did you rerun test_sync with O_DIRECT entabled, using my patch?  The
figures you had from test_fsync earlier were without O_DIRECT.

-- 
                                  -- Josh Berkus
                                     PostgreSQL Experts Inc.
                                     http://www.pgexperts.com