RE: performance issue for a specific column selection

Is there an index on hospital_id column, how big is the table?
 

 

 

 

Regards

Amit

 



-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]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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