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RE: performance issue for a specific column selection

From: Yasin Baskan <>
Date: Wed, 28 Sep 2005 13:51:09 +0300
Message-ID: <083667B535F3464CA0DD0D1DAFA4E37607479F65@camexc1.kfs.local>

Can you send the create script for HSTAB, is it a table, view, materialized view, etc...?

[] On Behalf Of raja rao Sent: Wednesday, September 28, 2005 1:37 PM To: oracle list
Subject: performance issue for a specific column selection

Hi All,

Can someone help me why a simple select is behaving strage:

select hospital_id,acct# from HSTAB where rownum=1;

This is almost taking 20 seconds to get the data. Where as teh same sql

without hospital_id column is taking just less than a second.

select acct#,mr# ,admit_dt from ...

This is taking less than a second. The only problem is with the hospital_id column.

When I checked the wait events, the below are the waits:

  SID EVENT                          MODULE
----- ------------------------------ -----------------------------------
USERNAME           P1         P2         P3
---------- ---------- ---------- ----------
   73 direct path write              SQL*Plus
OPS$ORACLE        201       6365          7

my db_files param is 200. So this file is temp file the wait is happening on.

I already have DISK_ASYNCH_IO=TRUE .

What else i have to do to fix this issue.

Thanks in advance,


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Received on Wed Sep 28 2005 - 10:03:00 CDT

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