RE: Lob Performance

From: <Laimutis.Nedzinskas_at_seb.lt>
Date: Fri, 27 Aug 2010 07:03:09 +0300
Message-ID: <OF8E45D1C2.69EAC2A0-ONC225778C.001595F9-C225778C.0016432B_at_seb.lt>

Metalink has some good articles. In my practice I've encountered the following issues:

• "hw contention" event which is for example fixed in 10.2.0.4 but the fix is not enabled by default. You have to set an event. Metalink has few articles how to detect if you are suffering and how to fix it.
• if lob is "small" (for example, average is 8K ) then enabling LOB caching improves performance. Note, that LOB's are supposed to be LARGE OBJECTS meaning caching is disabled by default else it would blow out the cache. But more often than not LOB size is something just above what ordinary varchar2 column would hold.

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             "Kenneth Naim"                                                
             <kennethnaim_at_gmai                                             
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             2010.08.23 13:22          RE: Lob Performance                 
                                                                           
                                                                           
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Yes, I have. I’m looking for something more definitive, less theory and more application.

Thanks,
Ken

From: Leyi Zhang (Kamus) [mailto:kamusis_at_gmail.com] Sent: Monday, August 23, 2010 2:34 AM
To: kennethnaim_at_gmail.com
Cc: oracle-l_at_freelists.org
Subject: Re: Lob Performance

Have you read online doc: Oracle® Database SecureFiles and Large Objects Developer's Guide
http://download.oracle.com/docs/cd/E11882_01/appdev.112/e10645/adlob_performance.htm#i1007089

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On Mon, Aug 23, 2010 at 6:01 AM, Kenneth Naim <kennethnaim_at_gmail.com> wrote:
I haven't dealt with lob performance much. Can someone point to a good site or whitepaper how to measure lob size, test and improve (b)lob performance. I'm checking google and mos and haven't found a comprehensive article.

Thanks,
Ken

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http://www.freelists.org/webpage/oracle-l Received on Thu Aug 26 2010 - 23:03:09 CDT