Re: select on 22 GB table causes "An I/O error occured while sending to the backend." exception - Mailing list pgsql-performance

On Thu, 28 Aug 2008, david@lang.hm wrote:
> I just asked on the kernel mailing list and Alan Cox responded.
>
> he is saying that you are correct, it only allocates against the total
> available, it doesn't actually allocate ram.

That was remarkably graceful of you. Yes, operating systems have worked
that way for decades - it's the beauty of copy-on-write.

> but you do need to allocate more swap as the total memory 'used' can be
> significantly higher that with overcommit on.

Yes, that's right.

Matthew

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