11g is consuming 100% CPU
DBAsupport.com Forums - Powered by vBulletin
Results 1 to 7 of 7

Thread: 11g is consuming 100% CPU

Hybrid View

  1. #1
    Join Date
    Apr 2010
    Posts
    5

    11g is consuming 100% CPU

    Hi, I have a problem with 11gR1(11.1.0.7).

    The application is only runnig one query every 5 seconds and other query every 3 seconds. There are not other activity with the application over the database.
    There is only one user in the application and the CPU consumption starts to rise up to 100%.

    The execution time for each query is 30ms. Furthermore, this problem only occurs in 11gR1. In 10g database (10.2.0.2 or 10.2.0.4) is not happening. We have running the same application since 4 years and this never happened.

    We update the statistics every day.

    Anyone have any idea?
    It happened something like this to someone?

    Thanks in advance,
    Federico

  2. #2
    Join Date
    Sep 2002
    Location
    England
    Posts
    7,333
    run statspack / awr and find out what is using the cpu

  3. #3
    Join Date
    Apr 2010
    Posts
    5
    The CPU is used by these queries, there are a lot of buffer gets and the top wait event is latch: cache buffer chain.
    The problem is that in other environment with Oracle 11g (11.1.0.7) and 10g these problems doesn't happen.
    My question is if the optimizer of 11g can change the execution plan, even if the statistics doesn't be updated. And in one moment to another the Oracle may be resolve the execution plan in the wrong way - is just a guess.
    The most rare is that these are optimized SQL statements.

    Any idea?

    I can't send the AWR (privacy policy), but if you need some part I will try.

    Thanks,
    Federico

  4. #4
    Join Date
    Apr 2010
    Posts
    5
    Please, check this link http://www.eggheadcafe.com/software/...ue-in-11g.aspx
    Is not the same issue, but is very strange

  5. #5
    Join Date
    Mar 2007
    Location
    Ft. Lauderdale, FL
    Posts
    3,554
    Operating System? is it Linux?

    What do you see in v$session_wait ?
    Pablo (Paul) Berzukov

    Author of Understanding Database Administration available at amazon and other bookstores.

    Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.

  6. #6
    Join Date
    Apr 2010
    Posts
    5
    PAVB, thanks for the answer.

    At the moment I don't have the information of v$_session_wait. I attach here an spreadsheet with AWR wait information and the SQL statements (please see rows in red and yellow).

    Thank you,
    Federico
    Attached Files Attached Files

  7. #7
    Join Date
    Apr 2010
    Posts
    5
    I forgot it, the operating system is Linux.

    The database has 2 nodes (RAC with failover) and it is configured with ASM.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  


Click Here to Expand Forum to Full Width