Re: High diskread ? why ?

From: <bialik_at_wis.weizmann.ac.il>
Date: Wed, 22 Apr 1998 15:54:02 -0600
Message-ID: <6hlldb$fmd$1@nnrp1.dejanews.com>

Hi.

The table's order make a difference! If you are joining only 2 tables, try and specify the table with a small number of rows second in the "FROM" clause. If you have more tables - use ORDERED hint.
High diskread number may be caused :
Full table scan execution( Index is not used or does not exist). Use EXPLAIN PLAN to check your statement.
The SGA size is too small.
You actually trying to read very large table. Try to limit the number of rows by using WHERE.

Good luck. Michael.

In article <6hjflp$et7$1_at_nnrp1.dejanews.com>, andrewl_at_tnl.com.au wrote:
>
> What causes high diskread per execution ?
>
> Is the order of tables referrenced on the from clause make a different ?
>
> Thanks,
> Andrew L
>
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-----== Posted via Deja News, The Leader in Internet Discussion ==----- http://www.dejanews.com/ Now offering spam-free web-based newsreading Received on Wed Apr 22 1998 - 16:54:02 CDT