Re: db file parallel write

1. You might want to check your MAX number of Async I/O servers on AIX. smit -> devices -> Asynchronous I/O -> Change/Show Characteristics I'm pretty sure you need to reboot if you increase the max number of servers ...
2. Also - what else is on the disk where the redologs reside on ?
3. If you have a 'lot' of JFS assigned to one JFS log, you might want to think about creating an extra JFS log to avoid contention...
4. Are your redologs on raid5 ?

Just some things to think about... don't know if it'll help you ...

Regards.

"Ethan Post" <Blah_at_Blah.com> wrote in message news:%1pe7.161543$%a.7114623_at_news1.rdc1.sdca.home.com...
> Just a little amendment. I do understand that waits are inevitable but I
am
> seeing some of there as long as "waited known time" of 16 seconds. - E
>
> "Ethan Post" <Blah_at_Blah.com> wrote in message
> news:XWoe7.161530$%a.7113965_at_news1.rdc1.sdca.home.com...
> > I have captured a bunch of session stats from V$SESSION_WAIT regarding
> event
> > "db file parallel write". The docs state the following.
> >
> > Parameters:
> > files
> > This indicates the number of files to which the session is writing.
> > blocks
> > This indicates the total number of blocks to be written.
> > requests
> > This indicates the total number of I/O requests, which will be the same
> as
> > blocks.
> >
> >
> > However, p1, data file is returning values like 204. There are not 204
> > datafiles in this database so where is this figure coming from? Also
> blocks
> > shows 0 and requests shows 0. Why is a wait occuring for no blocks and
no
> > requests. This is the same for status = waiting and status=waited known
> > time.
> >
> > DB_WRITERS=1. AIX 4.3.3 with the patch for async io. Oralce 8.1.6.3.
> > Should I increase DB_WRITERS in this case to eliminate these waits. The
> > waits are only occuring during a very intense batch processing job which
> we
> > are trying to speed up. DBWR is not the biggest bottleneck at this
point,
> > LGWR is.
> >
> > Thanks,
> > Ethan
> > http://www.geocities.com/epost1
> > http://www.freeocp.com
> >
> >
> >
>
>
Received on Wed Aug 15 2001 - 03:47:10 CDT