Hello All,

I think I am little bit lost in congiguration of SHMMAX parameter.

As per documantation on :

http://www.redhat.com/docs/manuals/database/RHDB-7.1.3-Manual/admin_user/kernel-resources.html

      Name Description Reasonable Values 
      SHMMAX Maximum size of shared memory segment (bytes) 512 KB + 8192 * 
buffers + extra ... infinity 


"The most important shared memory parameter is SHMMAX, the maximum size, in 
bytes, that a shared memory segment can have. If you get an error message from 
shmget along the lines of Invalid argument, it is possible that this limit has 
been exceeded. The size of the required shared memory segments varies both with 
the number of requested buffers (-B option) and the number of allowed 
connections (-N option), although the former is the dominant item. (You can 
therefore, as a temporary solution, lower these settings to get rid of the 
failures.) As a rough approximation you can estimate the required segment size 
as the number of buffers times the block size (8192 KB by default) plus ample 
overhead (at least half a megabyte). All error messages will contain the size 
of the failed allocation request. "




As far as I understood is 512 KB+8192*number of buffers times the block +0.5M.B

But I am not getting the count of number of buffres.
In postgres.conf file there is size of shared buffer.

shared_buffer=24 MB.

can anybody point me to number of buffers if i have understood correctly


Thanks In advance.

With Regards
Ashish...




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