Re: DBWR slave process

"Howard J. Rogers" <dba_at_hjrdba.com> wrote in message news:<aem712$kdk$1_at_lust.ihug.co.nz>...
> Version?
>
> If it's anything other than 7 or 8.0, you don't want to be messing with DBWR
> slaves, since they only parallelize the writing of buffers to disk. Instead,
> use the multiple DBWR processes feature, since they parallelize both on the
> buffer collection *and* the buffer writes. The two methods are incompatible
> with each other.
>
> DBWR slaves are configured using the DBWR_IO_SLAVES init.ora parameter.
> Multiple DBWR processes are configured using the DB_WRITER_PROCESSES
> init.ora parameter.
>
> As to why: because multiple processes (including slaves) mean that one
> process can be writing to data file 3 whilst another is simultaneously
> writing to data file 6. That means the writes are over quicker; checkpoints
> complete faster; I/O contention (between DBWR writing and your server
> process reading) is minimised. It's a thoroughly good thing, imho, where
> there are indications from statistics that DBWR I/O behaviour may be
> compromising performance.
>
> 8i permitted up to 10 ARCH processes. They get spawned automatically as the
> server detects the need for them, but you can spawn several at Instance
> startup by setting the LOG_ARCHIVE_MAX_PROCESSES init.ora parameter. That
> can be dynamically altered with an alter system command to manually cause
> the creation of additional processes, too.
>
> Regards
> HJR
>
>
>
>
> "Gaurang Patel" <gvpatel_at_hotmail.com> wrote in message
> news:14133c52.0206171628.56cf7d83_at_posting.google.com...
> > Can anyone explain me about DBWR slave process?
> >
> > Since we have DBWR process what is the need of DBWR SLAVE process?
> >
> > I heard something like async i/o and DBWR SLAVE help to achivw that.
> >
> > How?
> >
> > Is there any other SLAVE process for other oracle processes
> > like(LGWR,CKPT,ARCH ..etc)?
> >
> > Thanks

Hi Howard,
  We are running oracle 8.1.7

  So you mean insted of using DBWR SLAVE use multiple DBWR process.   

 Am i right?

 Another question
  What is the role of DB_BLOCK_LRU_LATCHES in DBWR process?   Can you explain that
 Thanks,

 -Gaurang Received on Tue Jun 18 2002 - 08:27:56 CDT