topic memory window for Oracle in Operating System - HP-UX

memory window for Oracle

Daniel Ubeda — Tue, 09 Oct 2001 11:37:51 GMT

I have one hp9000 server with 4Gb of RAM, HPUX 11.0 and Oracle 8i with two instances.
One of this with 1,6 Gb in SGA and the other with 23 Mb and I have not up more than this limit.
I read in metalink that there are a limit of 1,75 Gb for all instances, but with "memory window" implemented in HPUX.
Somebody know about this feature ??

Re: memory window for Oracle

Santosh Nair_1 — Tue, 09 Oct 2001 11:50:22 GMT

There should be a doc in /usr/share/doc called mem_wndws.txt that explains this feature and how to implement it. I've attached this document for your convenience:

-Santosh

Re: memory window for Oracle

James R. Ferguson — Tue, 09 Oct 2001 12:02:04 GMT

Hi Daniel:

Have a look here:

http://docs.hp.com/hpux/onlinedocs/os/memwn1_4.pdf

Regards!

...JRF...

Re: memory window for Oracle

Alexander M. Ermes — Tue, 09 Oct 2001 13:09:03 GMT

Hi there.
This depends on using a 32-bit or a 64-bit machine. If you use 32-bit Orcale, you have this limit of 1.75 GB for ALL sga's together without memory windows.
If you use 64-bit Oracle, no problem at all.
What server is yours ?
Rgds
Alexander M. Ermes

Re: memory window for Oracle

Bill Hassell — Tue, 09 Oct 2001 15:08:35 GMT

A memory window allows up to 3.75Gb of addressing space to be made available to a set of programs. Now the program cannot assign SGA to all of this space due to the limitations of a 32 bit application and process space quadrants (each = 1Gb). Read the white paper on memory management, specifically, SHARE_MAGIC.

Since you only have 4Gb, while you can create 2 separate windows and allocate the majority of the space to each instance of Oracle, it is highly likely the two instances will cause massive swapping. You may want to increase your RAM to 6-8Gb.