DBAsupport.com Forums - Powered by vBulletin
Results 1 to 5 of 5

Thread: log file sync?

  1. #1
    Join Date
    Mar 2005
    Posts
    26

    log file sync?

    well,my database is 8.1.7, in every statspack report, iam seeing in top 5 wait events the log file sync? can be tell me what is log file sync...
    Top 5 Wait Events
    ~~~~~~~~~~~~~~~~ Wait % Total
    Event Waits Time (cs) Wt Time
    -------------------------------------------- ------------ ------------ -------
    log file sync 184,512 240,604 8.20

    how to calculate from above report whether it's normal or abnormal? please tell me

  2. #2
    Join Date
    Nov 2000
    Location
    greenwich.ct.us
    Posts
    9,092
    "log file sync" typically represents the end of a transaction (commit or rollback). You are either over-committing or your redo logs are on very busy disks.
    Jeff Hunter

  3. #3
    Join Date
    May 2000
    Location
    ATLANTA, GA, USA
    Posts
    3,135
    In addition to that what Marist89 said, look at user commits value.
    Ask your self or talk to the appln team: is it reasonable number of commits from the application?

    If the application is written in JAVA, ask the developer to turn off auto commit.

    Tamil

  4. #4
    Join Date
    Mar 2005
    Posts
    26
    how to calculate from above report whether it's normal or abnormal? By this wait, wait time(TS) % Total Wt Time
    ),
    any value calculation
    please tell me

  5. #5
    Join Date
    Aug 2002
    Location
    Colorado Springs
    Posts
    5,253
    Originally posted by confident
    how to calculate from above report whether it's normal or abnormal? By this wait, wait time(TS) % Total Wt Time
    ),
    any value calculation
    please tell me
    No absolute formula, but it looks high. Whether it is or not depends on the nature of your application I suppose. It's an important wait event because it does directly impact your foreground processes.

    But as previous posters say, the most likely cause is over-commiting. Look for a section of code that does something like insert row-commit row-insert row-commit row etc..
    David Aldridge,
    "The Oracle Sponge"

    Senior Manager, Business Intelligence Development
    XM Satellite Radio
    Washington, DC

    Oracle ACE

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