[postgis-users] Rv: Postgis for Postgres 64 bits

Doug_Newcomb at fws.gov Doug_Newcomb at fws.gov
Fri Feb 24 10:18:08 PST 2012

Discussions on 32 bit vs 64 bit Postgresql:



See document on 5 steps to postgresql performance by Josh Berkus:
"64 bit performance can be 5-20% faster"


Doug Newcomb 
Raleigh, NC
919-856-4520 ext. 14 doug_newcomb at fws.gov
The opinions I express are my own and are not representative of the 
official policy of the U.S.Fish and Wildlife Service or Dept. of the 
Interior.   Life is too short for undocumented, proprietary data formats.

Andy Colson <andy at squeakycode.net> 
Sent by: postgis-users-bounces at postgis.refractions.net
02/04/2012 02:52 PM
Please respond to
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Re: [postgis-users] Rv:  Postgis for Postgres 64 bits

On 02/04/2012 01:14 PM, Darrel Maddy wrote:
> Dear Regina,
> I would be happy to contribute $100 into any fund which secures a 64-bit 
windows build of PostGIS2 -especially as I am about to install it on a 
machine with 64Gb RAM :)
> Count now at 1 ?
> Thanks
> Darrel
> http://www.ncl.ac.uk/gps/staff/profile/darrel.maddy#tab_profile

I really wonder if its faster.  I'd bet not.  If you consider the 
architecture, I'd bet, for all but the very largest of datasets, 32 bit PG 
running on top 64 bit os is faster.

Consider: you want the os disk cache to be as large as possible.  You want 
a bunch of shared mem and I'd bet around 2 gig would be a sweet spot. More 
shared mem wouldn't necessarily be a benefit. (There are upper bounds 
recommended for shared_buffers, especially on windows).

PG spawns a separate client for each connection, so each one of them could 
access up to 2 gig.  (so things like work_mem could be large).

And last, 32bit programs are faster because they move less data around 
(32bit pointers instead of 64bit).

Taken all together PostMaster + (clients * postgres.exe) + os cache could 
easly be more than 2 gig using 32 bit PG on 64 bit windows.

The only benefit of using 64bit PG would be a larger shared mem.  The 
online manual says: "The useful range for shared_buffers on Windows 
systems is generally from 64MB to 512MB"


The best use of ram, is as a disk cache, which 64 bit windows should use 
as much as possible (well, I assume).  After that there is nothing in 
Postgres (Per Client) that is going to run faster with more than 2 gig of 

Has anyone ever done any benchmarks?

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