Re: db_writer_processes tuning

Tim
>>There is an X$ table that summarizes activity to the different DBWn processes, but the name of it has slipped into the past and I can't recall it.
 
   Are you referring to x$kcbwds?

  1  select dbwr_num, sum(BUF_GOT),sum(SUM_WRT), sum(PREAD),sum(PWRITE) from x$kcbwds
  2* group by dbwr_num
SQL> /

  DBWR_NUM SUM(BUF_GOT) SUM(SUM_WRT) SUM(PREAD) SUM(PWRITE)
---------- ------------ ------------ ---------- -----------
         0    244517606     12940957  192045117    12940957
         1    244449224     12926116  192040603    12926116
         2    244416438     12930180  192024063    12930180
         3    244375475     12933143  192025129    12933143
         4    244345225     12925632  192029519    12925632
         5    244270375     12915465  192024015    12915465
         6    244268520     12927650  192025821    12927650

7 rows selected.


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Cheers

Riyaj Shamsudeen
Principal DBA,
Ora!nternals -  http://www.orainternals.com
Specialists in Performance, Recovery and EBS11i
Blog: http://orainternals.wordpress.com

On Mon, Feb 9, 2009 at 10:03 AM, Guillermo Alan Bort <cicciuxdba@xxxxxxxxx> wrote:

mine does... that is:
two thousand eight hundred and seventy five dollars rounds up to four
dollars ^_^

hth
Alan Bort
Oracle Certified Professional

On Mon, Feb 9, 2009 at 1:59 PM, Milen Kulev <makulev@xxxxxxx> wrote:
> Hello Nigel,
> it is definitely rounding error (2,875 -> 4 ;)  ).
> It is really pitty that my emplyer dowsn't round up my salary int this way
> ;)
>
> Anyway, the databases are running pretty well even with 4 DB writer
> processes.
>
> Best Regards. Milen
>
>
> Nigel Thomas wrote:
>
> Small thing:
>
> (16 + 7)/8 = 3, not 4
>
> WTF?
>
> 2009/2/9 Milen Kulev <makulev@xxxxxxx>
>>
>> Hello Vladimir,
>> as fas as know, according to Oracle the optimal count of DB writer
>> processes is
>> "(CPU_COUNT+7)/8". For 16 CPUs that would give you 4 DB Writer processes.
>> I have used this setting (also with VxFS), and there were no problems.
>>
>> HTH. MILEN
>>
>
>
>

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