RE: performance issue for a specific column selection

From: raja rao <raja4list_at_yahoo.com>
Date: Wed, 28 Sep 2005 05:00:50 -0700 (PDT)
Message-ID: <20050928120051.7336.qmail@web31404.mail.mud.yahoo.com>

Yes Amit.

Your question fixed the problem.

There is a bitmap index on the column. I just tried dropping that.

Thats excellent. It worked for me. Thanks for your time.

However, I have one more issue with the below query. Can you help me on this:

SELECT to_char(hName.ADT_LOADED_DATE,'yyyy-mm-dd hh24:mi:ss') "col1" ,

         to_char(hName.IMAGE_RECEIVED_DATE,'yyyy-mm-dd hh24:mi:ss'),
         floor(hName.CODED_LOADED_DATE-GREATEST(hName.ADT_LOADED_DATE,hName.IMAGE_RECEIVED_DATE)) "col2" ,
         hName.PATIENT_CASE_TYPE "case   " ,
         hName.drg_1,
         hName.CODED_LOADED_DATE,
         hName.ACCT# 
      FROM HOSP_AUXILIO hName 
          WHERE hName.PATIENT_CASE_TYPE
              in (select PST.PATIENT_CASE_TYPE 
                  from PATIENT_CASE_TYPE PST,HIM_PATIENT_CASE_TYPE HPST 
                  where PST.HOSPITAL_ID='AUXILIO' 
                 AND HPST.HIMCODE=PST.HIMCODE )
                                  and trunc(hName.CODED_LOADED_DATE) 
                 between to_date ('09/01/2005', 'mm/dd/yyyy') 
                 AND to_date('09/02/2005', 'mm/dd/yyyy') 
                 and hName.coded_flag='Y' 
                 and hName.adt_flag='Y'  
                 order by hName.ACCT#;

THe above query taking 9+ seconds to get the data.

The explain plan out put i like this:

SELECT STATEMENT
SORT ORDER BY
TABLE ACCESS BY INDEX ROWID HOSPITAL

      NESTED LOOPS
        VIEW  VW_NSO_1
          SORT UNIQUE
            HASH JOIN
              TABLE ACCESS FULL PATIENT_CASE_TYPE
              TABLE ACCESS FULL HIM_PATIENT_CASE_TYPE
        INDEX RANGE SCAN PAT_CASE_TYPE

But when i put the rownum <2 (to get 1 row output) it is taking less than a second. But when i remove teh rownum condition it is retrieving 9+ seconds to retrieve total of 148 records.

Can you help me why it is taking that much of time.

( query with rownum is:

         to_char(hName.IMAGE_RECEIVED_DATE,'yyyy-mm-dd hh24:mi:ss'),
         floor(hName.CODED_LOADED_DATE-GREATEST(hName.ADT_LOADED_DATE,hName.IMAGE_RECEIVED_DATE)) "col2" ,
         hName.PATIENT_CASE_TYPE "case   " ,
         hName.drg_1,
         hName.CODED_LOADED_DATE,
         hName.ACCT# 
      FROM HOSP_AUXILIO hName 
          WHERE hName.PATIENT_CASE_TYPE
              in (select PST.PATIENT_CASE_TYPE 
                  from PATIENT_CASE_TYPE PST,HIM_PATIENT_CASE_TYPE HPST 
                  where PST.HOSPITAL_ID='AUXILIO' 
                 AND HPST.HIMCODE=PST.HIMCODE 
                 and HPST.PATIENT_CASE_TYPE like '%') 
                 and trunc(hName.CODED_LOADED_DATE) 
                 between to_date ('09/01/2005', 'mm/dd/yyyy') 
                 AND to_date('09/02/2005', 'mm/dd/yyyy') 
                 and hName.coded_flag='Y' 
                 and hName.adt_flag='Y'  and rownum <2
                 order by hName.ACCT#;

Thanks,
RAj

amit.sharma_at_uk.nomura.com wrote:
Is there an index on hospital_id column, how big is the table?

Regards

Amit

-----Original Message-----

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org]On Behalf Of raja rao Sent: 28 September 2005 11:37
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,
Raj

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Received on Wed Sep 28 2005 - 07:03:08 CDT

RE: performance issue for a specific column selection - another tuneing issue