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Re: question about large pool

From: Tim Gorman <tim_at_sagelogix.com>
Date: Tue, 03 Jun 2003 08:24:54 -0800
Message-ID: <F001.005A8F77.20030603082454@fatcity.com>


The UGA contains cursors, session state info, etc. The PGA contains sort area, hash area, bitmap merge area, read buffers for direct-path, etc.

on 6/3/03 4:39 AM, Mladen Gogala at mgogala_at_adelphia.net wrote:

> Well, I was talking about cursors, sort areas and hash areas. I probably
> did confuse "GA stuff".
> On 2003.06.02 22:27 Tim Gorman wrote:
>> Almost.  It is the UGA areas (not the PGA) for Shared Server (a.k.a.
>> multi-threaded server) that are re-located to the Large Pool, if it exists.
>> Otherwise, they reside in the Shared Pool and all hell breaks loose,
>> performance wise...
>> 
>> Also, if DBWR_IO_SLAVES > 0, then those IPC queues will reside in the Large
>> Pool, if it is configured.  Otherwise, these reside in the Shared Pool, and
>> if you think having UGAs from Shared Server in the Shared Pool play hell
>> with performance, then wait until you are pushing all of your I/O to the
>> datafiles through the Shared Pool...  :-)
>> 
>> 
>> 
>> on 6/2/03 2:24 PM, Gogala, Mladen at MGogala_at_oxhp.com wrote:
>> 
>>> Nope, it's not accurate. PGA areas for shared server sessions are also
>>> allocated from the large pool.
>>> 
>>> Mladen Gogala
>>> Oracle DBA
>>> Phone:(203) 459-6855
>>> Email:mgogala_at_oxhp.com
>>> 
>>> 
>>> -----Original Message-----
>>> Sent: Monday, June 02, 2003 4:35 PM
>>> To: Multiple recipients of list ORACLE-L
>>> 
>>> 
>>> for some reason we have 100MB large pool. I dont think we need it at all. I
>>> read that its only used by RMAN or Parallel server. Is that accurate?

>>>>
>>>> From: DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
>>>> Date: 2003/06/02 Mon PM 03:39:42 EDT
>>>> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>>>> Subject: RE: question about large pool
>>>>
>>>> Use the large pool to store what? I can think of 3 aspects of a
>>> transaction:

>>>> - Rollback (you've probably read about SET TRANSACTION)
>>>> - SQL statements, execution plans (more an issue with bind variables)
>>>> - Data blocks
>>>> It sounds like you might be thinking of data blocks. You didn't mention
>>> your

>>>> Oracle version, but from 8i on you can define 3 buffer pools. The normal
>>> one

>>>> is DEFAULT. You can also define a KEEP and RECYCLE pool. Someone on this
>>>> list (sorry I can't recall who) pointed out that there isn't anything
>>> magic

>>>> about those labels. If your transaction uses different tables from the
>>> other

>>>> transactions, you could create what is needed for those tables in one of
>>>> those pools, assign the tables to that pool, and this would minimize the
>>>> interference. If all the transactions hit pretty much the same tables,
>>> then

>>>> Oracle is probably reusing the blocks anyway. Hope this responds to your
>>>> question.
>>>>
>>>> Dennis Williams
>>>> DBA, 80%OCP, 100% DBA
>>>> Lifetouch, Inc.
>>>> dwilliams_at_lifetouch.com
>>>>
>>>>
>>>> -----Original Message-----
>>>> Sent: Monday, June 02, 2003 1:40 PM
>>>> To: Multiple recipients of list ORACLE-L
>>>>
>>>>
>>>> I think I read this somewhere, but I cant find it. Is it possible to use
>>> the

>>>> large pool for a specific transaction? We run alot of large batch DML
>>>> statements over night. We have one that involves an 8GB table. The blocks
>>>> from this table are being knocked out of the buffer cache by shorter and
>>>> quicker batches.
>>>>
>>>> Id like to find to store this transaction in memory without having to
>>> worry

>>>> about them getting knocked out of memory.
>>>> Cache wont do it. It will stick get pushed out.
>>>>
>>>> --
>>>> Please see the official ORACLE-L FAQ: http://www.orafaq.net
>>>> --
>>>> Author: <rgaffuri_at_cox.net
>>>> INET: rgaffuri_at_cox.net
>>>>
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>>>> Author: DENNIS WILLIAMS
>>>> INET: DWILLIAMS_at_LIFETOUCH.COM
>>>>
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>> 
>> -- 
>> Please see the official ORACLE-L FAQ: http://www.orafaq.net
>> -- 
>> Author: Tim Gorman
>>   INET: tim_at_sagelogix.com
>> 
>> Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
>> San Diego, California        -- Mailing list and web hosting services
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Tim Gorman
  INET: tim_at_sagelogix.com

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Received on Tue Jun 03 2003 - 11:24:54 CDT

Original text of this message

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