Re: log file sync Wait

That was my understanding, too. Oh, and use bigger hammers, more nails and Australian beer.

Hately, Mike (NESL-IT) wrote:

>Yes, the lessons I took from that presentation were to use a shorter piece
>of string and buy larger bottles of gin though I'm willing to admit that I
>may have got the wrong end of the stick.
>
>=)
>
>Cheers,
>Mike
>
>-----Original Message-----
>Sent: 02 January 2003 09:24
>To: Multiple recipients of list ORACLE-L
>
>
>First of all I'd like to have the full picture of your performance: Log
>file sync might be 57% of the wait time, but how much of the response
>time is wait time?
>
>Second, Log File Sync means Commit; So if your system is waiting a lot
>for commits there are two things you can do: Fewer commits (changes to
>applications) or faster commits (hardware striping, etc.).
>
>No changes to the log buffer will help here (except perhaps making it
>smaller, as Connor McDonald so brilliantly showed during the funniest
>presentation I've ever seen in my life at UKOUG in Birmingham). If the
>log buffer is being flushed constantly, it's better to make it small so
>that it doesn't have to go through the whole thing every time.
>
>Mogens
>
>VIVEK_SHARMA wrote:
>
>
>
>>What ALL may be Done to Address the Following ?
>>Any /etc/system , init.ora parameter Changes too ?
>>Moving the Online Redo Logfiles onto RAID 1 NOT possible as that may
>>
>>
>warrant Additional Hardware . Moreover T3+ does NOT Support RAID 1 (Only
>RAID 1+ )
>
>
>>Concurrent Oracle processes = 1500 Approx.
>>Statspack Taken during Mostly OLTP Operations :-
>>
>>Top 5 Wait Events
>>~~~~~~~~~~~~~~~~~ Wait %
>>
>>
>Total
>
>
>>Event Waits Time (cs) Wt
>>
>>
>Time
>
>
>>-------------------------------------------- ------------ ------------
>>
>>
>-------
>
>
>>log file sync 970,563 2,597,831
>>
>>
>57.46
>
>
>>log file parallel write 831,141 484,948
>>
>>
>10.73
>
>
>>log_buffer = 2MB
>>Online Redo Logfiles Exist on RAID 1+
>>Storage Box is T3+
>>File System = UFS
>>
>>Application = Banking (Hybrid )
>>Oracle 8.1.7.4
>>Solaris 8
>>Machine Box = SF6800
>>
>>
>>
>>
>>
>>
>
>
>
>

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