Database Creation Questions

Thanks to those people who replied to my question on Redo Logs.

I have a couple more questions that I would appreciate some comments on if possible.

1. Is it possible/desirable to use the DB_DOMAIN parameter to set up a test database on a test server and a production database on a production server with the same database name, or should this parameter only be used for distributed databases.

The alternative would appear to be to use a different database name for each, which seems simpler but I am not sure of the implications down the line.

2) I have noticed that the Data Dictionary tables created during database creation (via the sql.bda script) extend quite rapidly. I have looked in the script and noticed that all these tables are created using default storage parameters. Do multiple extents on these tables have any adverse affect on performance or are they deliberatly supposed to extend? If this does affect performance do any DBA's amend the sql.bda script to add storage parms prior to creating a database?

Thanks in advance.

-- 
Ian Martin