log file sync?

[confident]

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

[marist89]

"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.

[tamilselvan]

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

[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

[slimdave]

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..