Reducing sga_target in 10gR2 without getting ORA-00827

From: Michael Ray <topshot.rhit_at_gmail.com>
Date: Fri, 16 Jun 2006 10:30:34 -0400
Message-id: <4492C08A.4090500@gmail.com>

To attempt to mitigate ORA-04030 crashes we've been experiencing, Oracle has suggested lowering sga_target. Unfortunately, the log/trace files have provided no clues at all as to what is causing this crash every 3-5 weeks. The server has 4GB of physical RAM, but is not using the /3GB switch so Oracle can only access 2GB. Currently sga_target is set at 1.2GB. The server runs only this 1 instance of Oracle so Windows has plenty of mem.

select * from v$sga_dynamic_free_memory gives 0 because sga_target=sga_max_size so Oracle has no memory to grow if needed. It shouldn't need to since 1.2GB should be way more mem than it needs for SGA.

Based on note 295626.1 I don't think I can reduce sga_target appreciably without getting ORA-00827 (could not shrink sga_target to specified value). Currently the sum of the min sizes

(select component, current_size/1024/1024 "CURRENT_SIZE",

	min_size/1024/1024 "MIN_SIZE",
	user_specified_size/1024/1024 "USER_SPECIFIED_SIZE"

from v$sga_dynamic_components)

is 1188 and sga_target is 1200.

Is there any way I can reduce sga_target to 1000 dynamically? Will I just have to keep doing it in small steps of 12 for example?

-- 

Sincerely,
Michael Ray
Topshot Systems LLC
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Received on Fri Jun 16 2006 - 09:30:34 CDT