Re: db_writer_processes tuning

  • From: Riyaj Shamsudeen <riyaj.shamsudeen@xxxxxxxxx>
  • To: cicciuxdba@xxxxxxxxx
  • Date: Mon, 9 Feb 2009 10:12:53 -0600

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.


-- 
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
> >>
> >
> >
> >
> --
> //www.freelists.org/webpage/oracle-l
>
>
>

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