Oracle-L: RE: PGA

From: Nelson, Allan <anelson_at_midf.com>
Date: Mon, 31 Mar 2003 07:43:38 -0800
Message-ID: <F001.005762CC.20030331074338@fatcity.com>

Hello Arvind,

This is sort of an open ended question. In general this parameter controls how much memory is allocated on a per session basis for in memory sorts. Sorts that require more memory than this will sort on the disk with a performance penalty. If you have the memory you should stay well north of 90% of your sorts in memory by bumping this parameter appropriately. The hitch comes when you consider the fact that an increase in this parameter uses the incremental amount that you increased sort area size and mulitplies it by the number of connected sessions. You can allocate enough memory this way to force your box to page if you are close to the line anyway. So you have a trade off. More memory to sort area size can reduce disk sorts and so speed up your process. UNIX will be happy right up to the point where you have to page or swap things to disk and at that point your system will crawl.

Allan

-----Original Message-----
Sent: Monday, March 31, 2003 4:04 AM
To: Multiple recipients of list ORACLE-L

hello all,

how does increasing the value of SORT_AREA_SIZE affect the unix system perfomance.

Thanks
Arvind
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Author: Arvind Kumar
INET: arvindk_at_sqlstarintl.com

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Author: Nelson, Allan
INET: anelson_at_midf.com

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