Setting the log size for Oracle case history databases

You might see a very high disk write queue length when using an Oracle database for case history. You can increase each redo.log file size to improve the disk write queue length.

To increase the redo.log file size:

1. If the redo log group associated with the log file has a status of CURRENT, you need to first switch it with another group:

   alter system switch logfile;

2. Deactivate the redo log group you want to drop:

   alter system checkpoint;

3. Drop the redo log group from the database.

   alter database drop logfile group group_number

   Restriction: If you only have two redo log groups active on the Oracle database, you cannot drop the group, since Oracle databases require a minimum of two active redo log groups at all times. If this is the case, create a third temporary redo log group before dropping either of the other two groups. For example:

   alter database add logfile group 3 '/app01/oratest/oradata/BOTI/BOTI/redo03.log' size 100M;

4. Delete the redo.log file associated with the redo log group you just dropped.
5. Add the group back to the database with a larger specified size. For example, if you want to create the redo log group with a size of 100 MB:

   alter database add logfile group 2 '/app01/oratest/oradata/BOTI/BOTI/redo02.log' size 100M;

   Repeat for all other redo log groups, making sure to make them inactive before dropping them.
6. Activate the last redo log group that you added:

   alter system switch logfile;

   Remember: If you originally had two redo log groups and you created a third temporary group to be able to drop the other two, you can delete this third group now.