db file parallel write

From: Ethan Post <Blah_at_Blah.com>
Date: Wed, 15 Aug 2001 06:48:23 GMT
Message-ID: <XWoe7.161530$%a.7113965@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 - 01:48:23 CDT