Most of the questions you have asked here were covered in my OpenWorld
presentation from 1997 called "The Mysteries of DBWR Tuning". It was based on
7.3 and is way out of date, but it is better than nothing. With that disclaimer
in mind, you can get it from http://www.ixora.com.au/tips/mystery.doc.


-----Original Message-----
Sent: Thursday, 31 August 2000 17:46


I am getting confused with the following DBWR related
TAGs .

 50 kcbswc DB writer IO clump
 16 kcbscc DB writer checkpoint clump
 13 kcbsdl DBWR blocks to scan lowest value
 50 kcbsdh DBWR blocks to scan highest value
  5 kcbsdi DBWR scan depth increment
 50 kcbsfs foreground blocks to scan looking for free
200 kcbnbh number buffer headers
247 kcbnbf number buffer objects

Total number of buffers =200 and the DBWR Write batch
size is 50. (i.e IO Clump).. But there are two more
otehr tags (kcbsfs and kcbsdh) are also 50. Does that
mean DBWR will scan so buffers (kcbnbh/4) all the
times whenever you need a free buffer in the hash
chain. And what is the difference between kcbscc and
kcbsfs.(both are kcbnbh/4 here).

And the other point of confusion here is the
difference in checkpoint clump and IO clump. What
parameter (or algorithm ) used in deciding the kcbsdl
and kcbscc .

I am using Oracle 8.0.3 with no buffer pools
configured if that matters.