Question

We have a feed process which runs every day of the year.
As part of that we delete every row from a table (approx 1 million rows) every day, repopulate it using 5 different stored procedures and then commit the transaction.
This is the only commit statement that we call.
All of a sudden the delete has started takign about 2 hours to complete.
The delete is also very simple (delete from T_PROFILE_WORK)
This has worked perfectly well for the past year, but in the past week I have noticed this issue.

Any help on this is greatly appreciated

Answer 1

please review the answers of this SO Question: “oracle delete query taking too much time”:

1. You could be blocked by another session (most likely). Before you
   delete you should make sure noone else
   is locking the rows, eg: issue SELECT
   NULL FROM tablename WHERE
   colname=:value FOR UPDATE NOWAIT,
2. There could be a ON DELETE TRIGGER that does additional work,
3. Check for UNINDEXED REFERENCE CONSTRAINTS pointing to this table
   (there is a script from AskTom that
   will help you determine if such
   unindexed foreign keys exist).

I would check #2 and #3 first, they are the easiest to diagnose.