These are background database server threads that perform housekeeping tasks, such as:

• Writing transactions to LOGDB
• Updating databanks
• Updating shadow databanks
• Forcing transaction updates to disk

There should be enough background threads to perform such tasks as quickly as possible. Generally the suggested number (3) is sufficient, but if the database uses databank shadowing or very large transactions this number may have to be increased.

You can determine the most appropriate number of background threads by increasing their number and restarting the database. Check the loading on each background thread by using MIMINFO with the performance option, or by monitoring their CPU usage using operating system tools. If some of the background threads are not being used, their number can be reduced.