Re: requested shared memory size overflows size_t

Tom,

A 32 bit build could only reference at most 4 Gb - certainly not 60 Gb. Also, Windows doesn't do well with large shared buffer sizes anyway. Try setting shared_buffers to 2 Gb and let the OS file system cache handle the rest.

Your other option, of course, is a nice 64-bit linux variant, which won't have this problem at all.

Good luck!

Bob Lunney

--- On Wed, 6/2/10, Tom Wilcox <hungrytom(at)googlemail(dot)com> wrote:

> From: Tom Wilcox <hungrytom(at)googlemail(dot)com>
> Subject: Re: [PERFORM] requested shared memory size overflows size_t
> To: pgsql-performance(at)postgresql(dot)org
> Date: Wednesday, June 2, 2010, 6:58 AM
> Hi,
>
> Sorry to revive an old thread but I have had this error
> whilst trying to configure my 32-bit build of postgres to
> run on a 64-bit Windows Server 2008 machine with 96GB of RAM
> (that I would very much like to use with postgres).
>
> I am getting:
>
> 2010-06-02 11:34:09 BSTFATAL:  requested shared memory
> size overflows size_t
> 2010-06-02 11:41:01 BSTFATAL:  could not create shared
> memory segment: 8
> 2010-06-02 11:41:01 BSTDETAIL:  Failed system call was
> MapViewOfFileEx.
>
> which makes a lot of sense since I was setting
> shared_buffers (and effective_cache_size) to values like
> 60GB..
>
> Is it possible to get postgres to make use of the available
> 96GB RAM on a Windows 32-bit build? Otherwise, how can I get
> it to work?
>
> Im guessing my options are:
>
> - Use the 64-bit Linux build (Not a viable option for me -
> unless from a VM - in which case recommendations?)
> or
> - Configure Windows and postgres properly (Preferred option
> - but I don't know what needs to be done here or if Im
> testing properly using Resource Monitor)
>
> Thanks,
> Tom
>
>
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