Re: Spread checkpoint sync

> Maybe, but it's hard to argue that the current implementation--just
> doing all of the sync calls as fast as possible, one after the other--is
> going to produce worst-case behavior in a lot of situations.  Given that
> it's not a huge amount of code to do better, I'd rather do some work in
> that direction, instead of presuming the kernel authors will ever make
> this go away.  Spreading the writes out as part of the checkpoint rework
> in 8.3 worked better than any kernel changes I've tested since then, and
> I'm not real optimisic about this getting resolved at the system level. 
> So long as the database changes aren't antagonistic toward kernel
> improvements, I'd prefer to have some options here that become effective
> as soon as the database code is done.

Besides, even if kernel/FS authors did improve things, the improvements
would not be available on production platforms for years.  And, for that
matter, while Linux and BSD are pretty responsive to our feedback,
Apple, Microsoft and Oracle are most definitely not.

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