Re: Oracle's max shmseg size on HP-UX

Actually, Rich, while your comment on Alpha/OSF SGA sizes should be true, in practice I have consistently corrupted my data dictionary on a 7.3.2.3 instance when attempting to do this on an Alpha 8400 running OSF/1 v. 3.2g. Ah smells a bug...

Regards,
jh

Rich Woods (rawoods_at_concentric.net) wrote:
: Brenda Muller wrote:
: >
: > Hi,
: >
: > I have gotten conflicting reports on the maximum amount of shared
: > memory that Oracle 7.3 can use on HP-UX 10.20. I know the
: > following:
: >
: > - HP-UX will not allow a single shmseg larger than ~1G
: > - HP-UX will not allow a single process to grab more than 2 shmsegs
: > - Oracle will grab one contiguous segment up to ~1G
: > - Oracle will grab two segments if each one < ~500M
: > - Oracle will fail if trying to grab two segments larger than ~500M.
: > This doesn't mean that both were larger than 500M - one could be
: > 520M and the other 200M and it will still fail.
: > - HP-UX will allow a single process to grab two shared memory segments
: > up to a total of 1.75G - each can be up to ~875M.
: >
: > We have tested the above points and they are facts.
: >
: > Oracle support has told us that Oracle can never take more than
: > 1G for an instance. It's unclear whether they mean Oracle in general
: > or Oracle on HP. I was (and am) under the impression that the max shm
: > size for Oracle is 2G. But the guy didn't seem overly impressive in
: > his knowledge, and he was difficult to deal with.
: >
: > We have a *huge* OLTP environment where we are trying to get our
: > data buffer block area as large as possible. Does anyone know of
: > a way to get around the above limitations?
: >
: > TIA,
: >
: > Brenda Muller
: >
: > -------------------==== Posted via Deja News ====-----------------------
: > http://www.dejanews.com/ Search, Read, Post to Usenet
: First of all, what did your Oracle7 7.3 for HP-UX 10.x Installation and
: Configuration Guide specify for shared memory and semaphore settings?
: That information comes from development and the porting groups, the
: folks whom are responsible for determining that information.
 

: I believe the 2GB/2 segment SGA cap is HP-specific, as all HP 9000
: platforms look alike to Oracle, from G30's to T520's.
 

: Also keep in mind that these are 32-bit processors, which will limit the
: size of a single address space. The DEC Alpha's, a 64-bit architecture,
: doesn't have this 2GB SGA limit.
: --
: Rich Woods
: Technical Field Support Specialist, Oracle Corporation, USA
: The above statements and opinions are my own and do not
: necessarily represent those of Oracle Corporation.

--
Jared Hecker - CODBA      |  ** HWA, Inc. **   Oracle and Sybase
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