Venu, this does help and this is what the guys on metalink said.
What I do not understand - what a waste. If I have to grab 100M initially on the OS side I may aswell use it. In my metalink tar I quoted many references in the documentation: E.G. In the Database Administration guide: Chapter 2: 'The size of the SGA is dynamic, and can grow or shrink by dynamically altering these parameters.' Now I would say grabing the SGA_MAX_SIZE for the entire uptime of the database is not what I would call dynamic. I can't see any growing or shrinking in SGA size. Stephen Hodgkinson Oracle DBA TotalFina Elf Gas & Power Ltd Phone: 01737 27 5564 [EMAIL PROTECTED] "Venu Gopal" <[EMAIL PROTECTED] To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> pro.com> cc: Sent by: Subject: RE: 9i - Dynamic SGA - SGA_MAX_SIZE [EMAIL PROTECTED] ity.com 01/08/03 12:14 Please respond to ORACLE-L Stephen, That's the way it's meant to work. This is how Oracle guarantees that you can grow upto the value of SGA_MAX_SIZE. Look at the case below: DAY 1: you have your sga_max set to 100m but you are currently using only 50m of it. DAY 2: you want to use all 100m and you try to increase the sga size, but some other app has used rest of the physical memory and there is no sufficient memory available, at this stage oracle has to error out saying 'insufficient memory', but in reality it does not!! In reality: On DAY 1, Oracle tries to occupy all 100m in the memory so that it doesn't have any issues in future... this way you have 100m reserved for oracle, use it whenever you want to use it. Hope this helps you... ~Venu -----Original Message----- [EMAIL PROTECTED] Sent: Friday, August 01, 2003 3:24 PM To: Multiple recipients of list ORACLE-L Hi, does anybody have any experience with setting the SGA_MAX_SIZE in 9i. I assumed the purpose of this parameter was that SGA would grow as requested to that limit. Example: You could configure your SGA to be 80M Set the SGA_MAX_SIZE to be 250M. I would have expected oracle to acquire 80M of memory from the UNIX machine. In fact using ipcs you can see that oracle will always acquire the value of SGA_MAX_SIZE. It acquires the extra space in the Variable Size of the SGA Sga_max_size=75m. Show sga: Total System Global Area 77041728 bytes Fixed Size 733248 bytes Variable Size 41943040 bytes Database Buffers 33554432 bytes Redo Buffers 811008 bytes sga_max_size=110M and keep everything else the same. show sga: Total System Global Area 114790680 bytes Fixed Size 733464 bytes Variable Size 79691776 bytes Database Buffers 33554432 bytes Redo Buffers 811008 bytes Database mounted. Database opened. I have raised a lengthy call on Metalink and the consultants are convinced this is normal behaviour and what you would expect. Do people agree with the metalink consultants? Maybe my expectations were to high but I thought a dynamic sga would mean I could change the amount of memory acquired by the UNIX box. All opinions welcome. I am on tru64 platform - 9.2.0.3.0 Thanks, Stephen ********************************************************************** This email contains information which is confidential. It is for the exclusive use of the addressee. If you are not an addressee please contact us immediately on 01737 275500. Please note that any distribution, copying or use of this communication or its contents is prohibited. 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