[postgis-users] OT Understanding slow queries

[Aren Cambre]

32 bit Windows is actually limited to 2 GB processes, or 3 GB if you start
Windows with a special */3GB* option.

Aren

On Thu, Sep 1, 2011 at 6:45 PM, Paragon Corporation <lr at pcorp.us> wrote:

> **
> Charles,
>
> Honestly I have little idea.  In theory you should fair better with Linux,
> but I think it depends on the kinds of processes you run how much better it
> is and how much ram you have.  One advantage that Linux has over windows
> (which is an advantage when running 32-bit Linux even, but more of an
> advantage I think when you are running 64-bit Linux) is that you can
> allocate more shared memory so processes that benefit on a lot of shared
> memory should benefit (basically processes where you are using more or less
> the same data in different ways can live in RAM.  Windows is limited not
> just for the 32-bit but also the 64-bit and I think this is just a
> fundamental flaw in PostgreSQL on windows.
>
> So generally speaking on windows I can't boost my shared memory more than
> say I think about 700 - 1GB without running into crashing issues.
> As far as work mem and so forth is concerned, on 32-bit windows you can
> have as much as 4GB per postgres process (and more with 64-bit windows) ,
> but of course if you are running
> Linux and 64-bit at that you can go up way more.
>
> I'm sure Linux folks will shoot me for saying this and chew me out, but I
> haven't really noticed much of a difference running my processes on 64-bit
> Linux vs. 32-bit window,
> but then again my processes are probably different from other peoples and I
> don't have a 32G ram Linux to take advantage of the massive more shared
> memory I can allocate.
>
> So on the low end (say 4-8GB ram range I suspect there isn't much of a
> difference, but when you get higher to the 32GB/64GB range, you would
> probably do a lot better with Linux.
>
> Thanks,
> Regina
>
>  ------------------------------
> *From:* postgis-users-bounces at postgis.refractions.net [mailto:
> postgis-users-bounces at postgis.refractions.net] *On Behalf Of *Charles
> Galpin
> *Sent:* Thursday, September 01, 2011 3:10 PM
> *To:* PostGIS Users Discussion
>
> *Subject:* Re: [postgis-users] OT Understanding slow queries
>
> Hi Regina
>
> I am revisiting this again.  How much of a performance difference should
> one expect to see between the 32 bit version and the 64 bit version of
> postgres when using PostGIS for typical gis queries like filtering by
> bounding box, locating nearest points etc? Depending on how I break up my
> data, I'll have anywhere from 200k to 260M records per table depending on
> how I partition it on a machine with 32G of ram.
>
> I am trying to make a case to use linux for a specific project but without
> being able to say there are significant gains (in performance) I'm just
> fighting an uphill battle. At best right now I can use the latest
> postgis/postgresql under windows but only 32 bit.
>
> Thanks,
> charles
>
>  On Aug 26, 2011, at 3:50 PM, Paragon Corporation wrote:
>
>   >  Sadly it's for immediate production use and I'm forced to use windows
> which limits my version choices a bit given my lack of skill under windows
> to build postgis :(
>
>  >  charles
>
> Charles,
>
> You know we do have pretty much latest builds of PostGIS (even trunk on
> PostGIS website for windows).
> http://www.postgis.org/download/windows/experimental.php
>
> and as far as PostgreSQL -- they have released windows binaries for even
> PostgreSQL 9.1 RC1
> http://www.enterprisedb.com/products-services-training/pgdevdownload
>
> Can't get too much more current than that (all without having to compile
> anything unless you are talking about the 64-bit versions).
>
> Thanks,
> Regina
> http://www.postgis.us
>
>
>
>
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