WHO LET THE DOGS OUT!!!
on 7/29/03 11:14 AM, Kirtikumar Deshpande at kirtikumar_deshpande_at_yahoo.com
wrote:
> But, I would like to know how this seemingly high wait for 'direct path write'
> is affecting the
> overall response time. (ResponseTime = WaitTime + ServiceTime)
>
> If the 'CPU used by this session' is not considered in light of these wait
> times, aren't you
> getting ready to bark at the wrong tree?
>
> - Kirti
>
>
> --- John Kanagaraj <john.kanagaraj_at_hds.com> wrote:
>> Hans,
>>
>> Now let me guess.... Your disks are all RAID 5, right? And you possibly are
>> bottlenecking on CPU as well? It is clear from the Top 5 that writes are an
>> issue across the board, to TEMP (direct path write), Redo (log file sync)
>> and DB files (db file parallel writes). Creating a RAID 1 set of disks and
>> moving at least the TEMP, RBS, Redo (and Arch if present) to this will
>> definitely help.
>>
>> John Kanagaraj
>> Phone: 408-970-7002 (W)
>> Fax: 408 327 3086 (Call/Email prior to fax)
>>
>>
>> -----Original Message-----
>> Sent: Tuesday, July 29, 2003 8:54 AM
>> To: Multiple recipients of list ORACLE-L
>>
>>
>> Hi All,
>>
>> Please help me tune this i/o related wait event. This is my 8.1.6 statspack
>> top-5 wait list:
>> Top 5 Wait Events
>> ~~~~~~~~~~~~~~~~~ Wait %
>> Total
>> Event Waits Time (cs) Wt
>> Time
>> -------------------------------------------- ------------ ------------
>> -------
>> direct path write 304,867 35,925
>> 49.83
>> log file sync 145,015 23,441
>> 32.52
>> db file sequential read 11,370 3,684
>> 5.11
>> file open 981 3,326
>> 4.61
>> db file parallel write 1,893 3,115
>> 4.32
>>
>> You'll notice that 'direct path write' is the most expensive one in the
>> list. I cannot find enough info on the net about this wait event, therefore
>> I'm asking the real experts.
>>
>> What events in Oracle trigger this wait event? In what way is this event
>> different from "db file parallel write"?
>> I mostly read comments that suggest lots of sorting and parallallel queries.
>>
>> However, most sorts are done in memory and degree = 0 for all tables.
>>
>> Any suggestions are very welcome.
>>
>> Thanks,
>> Hans de Git
>>
>>
>
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Received on Tue Jul 29 2003 - 13:39:23 CDT
