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Re: 2GB limit of memory for Oracle on WIndows 32 bit

From: <sybrandb_at_hccnet.nl>
Date: Sun, 01 Jul 2007 17:41:14 +0200
Message-ID: <3hif83l0g078e9cil62gdptjdgteoj9k05@4ax.com>


On Sun, 01 Jul 2007 08:14:17 -0700, zigzagdna_at_yahoo.com wrote:

>On Jun 27, 12:01 pm, BD <robert.d..._at_gmail.com> wrote:
>> On Jun 27, 8:44 am, zigzag..._at_yahoo.com wrote:
>>
>> > I am on Windows 2000 server and usng Oracle 9.2.0.6. I know 32 bit
>> > Oracle has limit of 2GB memory. I have 5 Oracle database instances, so
>> > I see 5 oracle.exe in task manager. I am assuming each oracle.exe can
>> > access up to 2GB memory, so up to 10GB memory can be used by Oracle on
>> > the server.
>>
>> > Thanks a lot.
>>
>> No, not exactly. You have 2GB of memory for *all* of the Oracle
>> requirements. It's gross.
>>
>> 3 ways of dealing with that limitation:
>>
>> 1: the /3GB switch in boot.ini: allows for 3GB to be made available to
>> programs, with the kernel taking 1GB (could be repercussions there
>> too)
>>
>> 2: the /PAE switch in boot.ini: allows for use of upper memory
>> (anything above 4GB). Oracle needs to be configured to use this
>> memory, and this memory can only be used for the buffer cache. Shared
>> Pool, PGA, all the rest needs to sit in 'base' memory no matter what.
>>
>> The /3GB and /PAE switches can be used together, but if they are, you
>> will never see more than 16GB on the box, even if there's 64GB of
>> physical memory installed. Just the way it works.
>>
>> 3: Use 64-Bit windows.
>>
>> BD
>
>>>2: the /PAE switch in boot.ini: allows for use of upper memory
>>> (anything above 4GB). Oracle needs to be configured to use this
>>> memory, and this memory can only be used for the buffer cache. Shared
>>> Pool, PGA, all the rest needs to sit in 'base' memory no matter what.
>
>Is there any thing wrong is using /PAE switch and setting some
>parameters in init.ora to put buffer pools in this address space.I
>want to have large buffer pool so I can "pin" some tables in memory
>using
>recycle pool. In addition, increase size of my default buffer pool. I
>have 8GB memory on the server, some of it wll betaken kernel and other
>oracle parameters - PGA etc, bur rest I can use for buffer pools.
>
>
>

Recycle pool does not *pin* tables in memory. Tables can be kept longer in memory by using the *keep* pool (funny name isn't it, if you think of it).

Apart from that cranking up the memory won't resolve your fundamental problem: apparently you never tuned your application and now you want to resolve that by throwing memory at the problem. This method has been demonstrated to be fundamentally wrong over and over again, and is one of the safest methods to end up in hell or at the unemployment office.

-- 
Sybrand Bakker
Senior Oracle DBA
Received on Sun Jul 01 2007 - 10:41:14 CDT

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