Originally posted by hrishy
Hi sonia

In many many situations..whenever dbwr is signalled to write dirty block to the database it just does that..and that dirty blocks will contain uncomitted data..now there are many conditions under which the dbwr flushes dirty buffers to disk and under these conditions dbwr will not check wheather the blocks contain comitted data or not it just flushes..

regards
Hrishy
Hrishy is right. For instance, DBWR wakes up every three seconds and writes all the dirty buffers to the data files (in Oracle 8i).

During instance recovery, SMON Rollsback all the uncommitted transactions.