On Fri, Jul 22, 2011 at 10:15:08PM -0400, Greg Smith wrote:
> On 07/22/2011 08:15 PM, David Fetter wrote:
> >Do you have any theories as to how indexing on SSD speeds things
> >up? IIRC you found only marginal benefit in putting WALs there.
> >Are there cases that SSD helps more than others when it comes to
> >indexing?
>
> Yes, I've found a variety of workloads where using a SSD turns out
> to be slower than the old-school array of drives with a
> battery-backed write cache. Tiny commits are slower, sequential
> writes can easily be slower, and if there isn't a random I/O
> component to the job the SSD won't get any way to make up for that.
So you're saying this is more of a flash thing than an SSD thing? I
haven't heard of systems with PCM having this limitation.
Cheers,
David.
--
David Fetter <david@fetter.org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david.fetter@gmail.com
iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics
Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate
