Re: Indexes on RAM disk = insanity?

Steve Lane wrote:

>All:
>
>We have a postgres 7.4 server where we're trying to achieve some speedups.
>Right now, at least superficially, RAM appears to be the bottleneck -- lots
>of swaps in and out.
>
>There is another consultant beside myself in the mix and he asked this
>question: can we put the database indexes on a RAM disk? Won't that speed
>things up?
>
>
I am quite wary about putting the indexes on a RAM DISK for another reason.

You say that RAM is your bottleneck, so putting anything unnecessary in
RAM seems like a good way to get less performance rather than more.
Additionally you have some overhead in tracking the files, etc. and they
will remain in RAM even when they are not used. This leaves the system
with less effective RAM for the memory intensive operations.

Such a move might make a lot of sense if you had a LOT of RAM but disk
I/O was the bottleneck. However, if a lack of RAM is your problem,
putting more stuff in RAM doesn't seem very sound to me.

Best Wishes,
Chris Travers
Metatron Technology Consulting