Re: [HACKERS] Neverending query on 6.5.2 over Solaris 2.5.1

Fernando Schapachnik <fpscha@ns1.via-net-works.net.ar> writes:
>> enough buffer space to avoid thrashing.  You need to increase your
>> kernel's max-shared-memory-block-size (SHMMAX, I think) parameter
>> so that you can run with a more reasonable -B setting.  A lot of
>> kernels ship with SHMMAX settings that are ridiculously small for
>> any modern machine.

> What value would you advise for shmmax?

Well, with the default number of buffers (64) Postgres requires about
a megabyte (I think a tad over 1Mb, in 6.5.*).  Extra buffers are 8K
plus a little overhead apiece.  If you are running with more than a
couple of active backends at a time then you probably want to use
more than the default number of buffers.  But I have no advice on
how many is appropriate for what size of installation --- can anyone
else help?
        regards, tom lane