Re: Fwd: Out of Memory and Configuration Problems (Big Computer)

Stephen,

You're a legend! That is exactly the answer I needed to hear from someone
who actually knows the score. I am now powering on with Plan B: Postgres64
on Linux64.

After relentless searching I have become fairly convinced that a stable
release of 64-bit postgres for Windows doesn't exist yet. (I welcome anyone
to show me otherwise). Since I am committed to postgres (already written the
code, it works just not quickly), I will have to change my OS.

However, if these performance limitations on Windows were apparent to me
from the start, I probably would have chosen MS SQL Server over Postgres
(less pain to get the gain). Perhaps this is an argument in favour of 64-bit
Windows port to be added to this list:

http://wiki.postgresql.org/wiki/64bit_Windows_port

Thanks again for all your help.

Tom

On 2 June 2010 15:27, Stephen Frost <sfrost(at)snowman(dot)net> wrote:

> Tom,
>
> * Tom Wilcox (hungrytom(at)googlemail(dot)com) wrote:
> > The impression I was getting from Magnus Hagander's blog was that a
> 32-bit
> > version of Postgres could make use of >4Gb RAM when running on 64-bit
> > Windows due to the way PG passes on the responsibility for caching onto
> the
> > OS.. Is this definitely not the case then?
>
> Eh, sure, the data will be cache'd in the Windows OS, so more data will
> be in memory, but you're never going to be able to use more than 4G for
> any actual *processing*, like sorting, doing hash joins, having data in
> shared buffers (to avoid having to go back to the OS and doing a system
> call to get the data from the OS's cache..).
>
> Not only that, but the shared_buffers are in *every* backend, so while
> you'll only use 512MB for shared_buffers total, each backend will only
> have 3.5G (or so) of memory to do 'other stuff'.
>
> On a box with 16GB that's doing alot of relatively small activities
> (OLTP type stuff), PG will work "alright". On a box with 96G with
> terrabytes of data where you want to do data warehousing kind of work,
> running a 32bit version of PG is going to suck.
>
> Thanks,
>
> Stephen
>
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