RE: 9.2 - Parallel Query Not Working

  • From: David Aldridge <david@xxxxxxxxxxxxxxxxxx>
  • To: RS2273@xxxxxxx, mwf@xxxxxxxx, Oracle List <oracle-l@xxxxxxxxxxxxx>
  • Date: Thu, 28 Feb 2008 12:57:05 -0800 (PST)

No, not RAC. 

"Shamsudeen, Riyaj" <RS2273@xxxxxxx> wrote:        v\:* 
{behavior:url(#default#VML);}  o\:* {behavior:url(#default#VML);}  w\:* 
{behavior:url(#default#VML);}  .shape {behavior:url(#default#VML);}             
   David
              Is this RAC? Can you print exactly values for 
parallel_instance_group and instance_groups?
      
---------------------------------
  
  From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
Behalf Of Mark W. Farnham
Sent: Thursday, February 28, 2008 11:17 AM
To: david@xxxxxxxxxxxxxxxxxx; 'Oracle List'
Subject: RE: 9.2 - Parallel Query Not Working

   
  How much of that table is already in the buffer cache when PQ stops being 
operative?
   
  mwf
   
      
---------------------------------
  
  From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On 
Behalf Of David Aldridge
Sent: Thursday, February 28, 2008 12:03 PM
To: Oracle List
Subject: 9.2 - Parallel Query Not Working

   
    On a 9.2.0.6 database on Solarix 64, which is created every day from a 
magical SAN-based mirror process thing (excuse the tech talk), we alter a 
particular table to a default degree of parallelsim of 12. A process which 
performs a full scan of that table picks up the degree of 12 and completes in a 
couple of hours.

     

    Later in the day we can no longer prompt the instance to give any 
parallelism. 

     

    I've tried everything obvious ... setting parallel_adaptive_multiuser to 
false, parallel max servers to 48, used hints, made sure the table's default 
dop is 12, checked that PROCESSES is reasonably high (500+), that the server is 
not very busy (less than 10 active sessions), ALTER SESSION FORCE PARALLEL 
QUERY, but nothing we do will prompt PQ to be used on even the most simple 
SELECT * FROM ... queries.

     

    Any thoughts on this are much appreciated.



Other related posts: