Re: SHMMAX and SHMALL question

On Fri, Jan 21, 2011 at 6:34 PM, DM <dm.aeqa@gmail.com> wrote:
> Firstof all sorry for posting linux kernel question in pgsql-general, but i
> am trying to figure out what value to set for postgresql db server.
>
> RAM = 16GB, what value should i set for shmall?
>
> If i set shmall to 4294967296 (4GB),

shmall is measured in 4096 byte pages.  So, you wouldn't set it to
~2^32, but 2^32/2^12 so you'd set it to 2^20 or 1M pages for 4G of
space.

> current PAGE_SIZE is 4096 should i need
> to set my shmmax = 4294967296*4096 = 17592186044416?

shmmax is set in bytes, so no translaction needed, just set it to 2^32

(reference:
http://publib.boulder.ibm.com/infocenter/db2luw/v9/index.jsp?topic=/com.ibm.db2.udb.uprun.doc/doc/t0008238.htm)