Need help : degrading performance in record updates

We are facing some problem in our batch application. This java based application is reading a file with 25 lakh records and updating in Oracle DB.
The batch is commited after each 300 records. We are taking a time stamp after each 10000 records.

What we have observed is, initial it was taking some 3-4 seconds to update 10000 records.
The time required is increasing progressively. After 12 Lakh records, now it is taking almost 10+ mins to update 10000 records.

I have failed to pin down a problem, for such continuously degrading performance.
This is important for us because, we have such 16 files to upload. And this upload is just data preparation for the analysis that we need to perform on one bug that is observed on production.

I think, Re-do logsize of Oracle should not be a problem since we are committing every 300 records. Received on Thu May 10 2007 - 22:39:48 CDT