Re: [INTERFACES] IPC Shared Memory (fwd)

From: Peter Schindler <pschindler(at)synchronicity(dot)com>
To: Katsuyuki Tanaka <katsut(at)cse(dot)unsw(dot)EDU(dot)AU>
Cc: pgsql-general(at)postgresql(dot)org, pgsql-admin(at)postgresql(dot)org
Subject: Re: [INTERFACES] IPC Shared Memory (fwd)
Date: 2001-02-26 08:51:02
Message-ID: B0021212521@tellurian.net
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Katsu,

Katsuyuki Tanaka wrote:
> hi i'm re-sending this mail again to seek more help since i haven't got
> any solution as yet. Additionaly , could it be an oracle taking up so much
> resource so that i postgres can't get any of them?

Yes, I think your oracle db doesn't probably leave enough for PG.
I don't know how much of the shared resources are necessary for PG,
but I assume you have problems with the number of semaphores.

I had similar problems and I didn't want to reconfigure the systems, so I
reduced the PROCESS parameter for oracle.

Have a look at the following description, on how to set and calculate the
shared memory/semaphores for Oracle on UNIX (I assume you use Solaris):

http://otn.oracle.com/doc/solaris/server.815/a67457/pre.htm#1000595

That's the only version I found in HTML form, so if you have a different
oracle version you might have to check your specific installation guide
for that, but in principle the calculations are still the same for the
different oracle versions, I think.

e.g. for 8.1.7 solaris
http://otn.oracle.com/docs/products/oracle8i/pdf/installguide_sun_817.pdf

> i made query to admin and the max shared mem setting is already
> set to the max possible
> *
> * IPC Shared Memory
> *
> 4294967295 max shared memory segment size (SHMMAX)
> 1 min shared memory segment size (SHMMIN)
> 100 shared memory identifiers (SHMMNI)
> 10 max attached shm segments per process (SHMSEG)
Yes, the (SHMMAX) seems to be max, but the others could be higher. The
same is true with the semaphore parameters. But those parameter influence quite
a bit how many resources are reserved from the kernel (-> needs memory)
So, the settings should balance your needs and available memory.

--
Best regards,
Peter Schindler
Synchronicity Inc. | pschindler(at)synchronicity(dot)com
http://www.synchronicity.com | +49 89 89 66 99 42 (Germany)

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