RE: Lob Performance
- From: "Kenneth Naim" <kennethnaim@xxxxxxxxx>
- To: <Laimutis.Nedzinskas@xxxxxx>, <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 27 Aug 2010 12:22:57 -0400
Our application supposedly fixed the lob issue with a patch, but the patch
blew up on our system so I haven't been able to test it. Once we fix this
issue I'll restest it as a baseline. I noticed in their script the offending
lob table hasn't changed, so my changes will be on top of their
improvements. Unfortunately I'm not sure what improvements they have made as
it is in their binaries.
Thanks, I'll update the thread once I am able to test my improvements.
Ken
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]
On Behalf Of Laimutis.Nedzinskas@xxxxxx
Sent: Friday, August 27, 2010 12:03 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: RE: Lob Performance
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@gmai
l.com> To
Sent by: "'Leyi Zhang \(Kamus\)'"
oracle-l-bounce@f <kamusis@xxxxxxxxx>
reelists.org cc
<oracle-l@xxxxxxxxxxxxx>
Subject
2010.08.23 13:22 RE: Lob Performance
Please respond to
kennethnaim@gmail
.com
Yes, I have. I'm looking for something more definitive, less theory and
more application.
Thanks,
Ken
From: Leyi Zhang (Kamus) [mailto:kamusis@xxxxxxxxx]
Sent: Monday, August 23, 2010 2:34 AM
To: kennethnaim@xxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: Lob Performance
Have you read online doc: OracleR Database SecureFiles and Large Objects
Developer's Guide
http://download.oracle.com/docs/cd/E11882_01/appdev.112/e10645/adlob_perform
ance.htm#i1007089
--
Kamus <kamusis@xxxxxxxxx>
Visit my blog for more : http://www.dbform.com.
Join ACOUG: http://www.acoug.org.
On Mon, Aug 23, 2010 at 6:01 AM, Kenneth Naim <kennethnaim@xxxxxxxxx>
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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