Re: Help me tuning this wait event:log file sync

There is a package on my web site which takes snapshots of various v$ object, much as statspack does, but for near real-time feedback.

One of the procedures it contains handles v$session_event.

Take a session snapshot of (say) a ten minute period and see how significant the "log file sync" is to each session.

Alternatively:

    break on sid skip 1

    select sid, event, time_waited/100
    from v$session_event
    order by sid, time_waited desc

log file sync's are highly exaggerated at the v$system_event level. Your largest problem is an I/O problem - look at the average I/O wait time (on reads and writes). Because you are doing "20 - 40" commits per second, you "log file sync" time looks 20 - 40 times as bad as it really is.

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Jonathan Lewis
http://www.jlcomp.demon.co.uk

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chao_ping wrote in message <3d2fd3a1$2_at_usenetgateway.com>...



>I don't quite understand your words"Look at the session level - is any

>one session being impacted significantly by log file sync ?", we are

>using tuxedo middleware and do users do not directly connect to

>database.