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RE: performance issue for a specific column selection

From: <>
Date: Wed, 28 Sep 2005 10:24:48 -0500
Message-id: <>

also can you post the explain plan for the one w/o the hospital_id and the one with it..


                      Yasin Baskan                                                                                                      
                      <        To:, oracle list <>                     
                      .tr>                      cc:                                                                                     
                      Sent by:                  Subject:  RE: performance issue for a specific column selection                         
                      09/28/2005 05:51                                                                                                  
                      Please respond to                                                                                                 

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

From: [] 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 - 10:27:12 CDT

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