MULTI-LOCK IO

From: DBA Deepak <oracle.tutorials_at_gmail.com>
Date: Sat, 25 Aug 2007 22:33:42 +0530
Message-ID: <75aa80160708251003y1b10ccd2hbec0cb52c6f09f4b@mail.gmail.com>

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.

--

Regards,

Deepak
Oracle DBA

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http://www.freelists.org/webpage/oracle-l Received on Sat Aug 25 2007 - 12:03:42 CDT