[users] Re: [newpkgs] New PostgreSQL packages

[Mark Round]

Daniel Seichter wrote:

 >Hello Mark,
 >
 >thank you for your answer. My database is at the moment about 3GB and
 >only contains text. Is there a size of database where 64bit results a
 >higher performancel than 32bit?
 >
 >Thanks
 >Daniel
 >

Hi!
Sorry for the delay in responding, I've been doing some digging around, 
to see what I could find.
I've never myself run a database of that size, so it's hard for me to 
say - the only way you'll ever really be
sure is to do some benchmarking yourself, comparing the performance of 
the two servers. However,
I did find the following which seems to answer your question - the cut 
off point seems to be around the
5Gb mark (assuming you trust someone anecdotal evidence...)  :-

"Performance of 32-bit cpu machines will decline rapidly when the 
database size
exceeds 5 GigaByte. You can run 30 gig database on 32-bit cpu but the 
performance
will be degraded. Machines with 32-bit cpu impose a limitation of 2 GB 
on RAM,
2 GB on file system sizes and other limitations on the operating system.
...
For extremely large databases, it is strongly advised to use 64-bit 
machines  
Compile PostgreSQL under a 64-bit cpu and it can support huge databases and
large queries.
...
Performance of PostgreSQL for queries on large tables and databases will be
several times faster than PostgreSQL on 32-bit cpu machines. Advantage 
of 64-bit
machines are that you get very large memory addressing space and the 
operating
system can support very large file-systems, provide better performance
with large databases, support much larger memory (RAM), have more 
capabilities etc..
"

(Taken from 
http://www.collaborium.org/onsite/venezuela/docs/linux/Linux_HOWTOS/PDF/PostgreSQL-HOWTO.pdf)

-Mark