Here's a good one.

I 'maintain' a database for a live app. Bit of a black box as it was delivered ready built. All I did was create some tablespaces and datafiles for the dev team to run scripts in.

Its 8i Standard edition, by the way.

The SYSTEM tablespace was created with a datafile of SIZE 100Mb.

I've noticed that the datafile size is growing. The actual size of the SYSTEM data isn't - just the file size. Over the last few weeks the size of the SYSTEM data has remained constant at 52Mb - But the filesize itself has grown from 138Mb (when I first noticed) in Dec '02 to 191 Mb as of today.

Using :
select file_name, (bytes/1024/1024)
from dba_data_files

I can see the SYSTEM.dbf being 191 Mb in size.

So if the data isn't being added to (ie) no new objects being created, how can the filesize increase?