[postgis-users] Shared memory extesion on a a Mac for PostgreSQL/PostGIS

Scott Brunza scottso at sonalysts.com
Tue Mar 8 05:28:25 PST 2011


I've several systems with 8-24 GB of RAM running postgres and postgis.  I built postgres as a 64-bit executable to take advantage of the larger address space.  As a rule for databases, they are memory hungry.  I generally follow:  effective cache size, 50% RAM; shared_buffers, 25% RAM.  There are other PG tuning parameters available in performance docs/discussions on the web.

With only 2GB of RAM, the bit-width of postgres shouldn't matter, and your setting of 1.5 GB shmmax seems a little too large.  Try keeping it below 1.25 GB, or even 1 GB.  Since you said this is only a prototype, performance shouldn't be a top priority.  You also don't want to starve the OS of resources.  Consider starting with your postgres setting half or even a quarter of what I stated above.  Also, consider lowering the max_connections setting; each connection requires more shared memory.  This way you can also limit the size of your kernel resources.

You can also dynamically change the kernel parameters with `sysctl -w PARAMETER=VALUE` from the command line to find a setting you're comfortable with before committing it to /etc/sysctl.conf.  The only reason to have large memory space for postgres is to store as much of the database as possible in memory, i.e., faster access and less/no swapping.

As for the pgAdmin question, it's a good tool, but it ultimately comes down to what you're comfortable with.  I prefer the command line.

Hope that clears things up at least a bit.
-B-


--- Let us all bask in television's warm glowing warming glow ---
Scott Brunza           860.326.3637         scottso at sonalysts.com

This e-mail and any files transmitted with it may be  proprietary
and are  intended solely for the use of the  individual or entity
to whom they are addressed.  If you have received this  e-mail in
error please notify the sender.

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/postgis-users/attachments/20110308/344ac6b8/attachment.html>


More information about the postgis-users mailing list