RE: MULTI-LOCK IO

What version of Oracle?  

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Mark J. Bobak
Senior Database Administrator, System & Product Technologies ProQuest
789 E. Eisenhower, Parkway, P.O. Box 1346 Ann Arbor MI 48106-1346
+1.734.997.4059 or +1.800.521.0600 x 4059 mark.bobak_at_il.proquest.com <mailto:mark.bobak_at_il.proquest.com> www.proquest.com <http://www.proquest.com> www.csa.com <http://www.csa.com>

ProQuest...Start here.  

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of DBA Deepak Sent: Saturday, August 25, 2007 1:04 PM
To: oracle-l
Subject: MULTI-LOCK IO  

Hi All,  

I have few doubts on Multiblock IO.

I have a DB which runs on mixed load i.e., OLTP & DSS. We have few big tables which require FTS for
reporting and other relatively smaller tables need indexed access. Our DB block size is 8K.

My queries are:

1> If I set db_file_multiblock_read_count=128 (MAX_IO_SIZE=1M) then the optimizer may choose FTS
for the other queries as well. Can I set optimizer_index_cost_adj=10 to influence/override the FTS
decission?

2> Is it a good idea to set db_file_multiblock_read_count=128 at the session level wherever FTS is
required?

3> Will the system statistics override the db_file_multiblock_read_count settings?

Please help me on this.

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Regards,

Deepak
Oracle DBA

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http://www.freelists.org/webpage/oracle-l Received on Sat Aug 25 2007 - 12:55:17 CDT