RE: Problem with large SGA

From: Jesse, Rich <Rich.Jesse_at_quadtechworld.com>
Date: Fri, 7 Oct 2005 14:33:35 -0500
Message-ID: <FB5D3CCFCECC2948B5DCF4CABDBE66971FFC44@QTEX1.qg.com>

Have you tried to trace the session that runs the ALTER? Seems like a logical place to start.  

Rich

	-----Original Message-----
	From: oracle-l-bounce_at_freelists.org

[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of daniel.hubler_at_aurora.org

	Sent: Friday, October 07, 2005 1:24 PM
	To: oracle-l_at_freelists.org
	Subject: Problem with large SGA
	
	

	Oracle v8.1.7.4 
	OpenVMS 7.3-2 
	
	We recently increased the size of our SGA from 40gig to over
100gig by increasing our shared pool and block buffer cache. 
	Everything has gone very well. 
	
	One side effect we have encountered is that the time it takes to
put all our tablespace into HOT backup 
	(ALTER TABLESPACE xxxxx BEGIN BACKUP;) 
	has gone from 1 hour  to  about 3.5 hours. 
	In retrospect, this makes some sense as the buffer cache is
examined for blocks from the specific 
	tablespace to be written to disk;  more cache to examine so it

takes more time.         

        Oracle has confirmed this. We have received the "expected behavior" answer regarding this issue.         

        Anybody have any ideas on how to minimize the impact of this?                                                      

	Dan Hubler
	Database Administrator
	Aurora Healthcare
	daniel.hubler_at_aurora.org

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Received on Fri Oct 07 2005 - 14:37:41 CDT