SAP on Oracle FAQ
Oracle on SAP (R3) FAQ:
 Can I use Oracle's tools to do DB admin or should I use SAP tools?
Do as much as you can through the SAP GUI and provided SAP Transactions. Try to make Oracle level changes only when absolutely necessary. This will ensure that your Oracle and SAP data dictionaries are kept in sync.
Some of the SAP admin programs:
- BRBACKUP (backup the database)
- BRARCHIVE (backup off-line redo logs)
- BRRESTORE (restoring the database and the redo logs)
- SAPDBA (database administration. Eg: database startup and shutdown, space analysis, tablespace extensions, monitoring, reorganization, database recovery). You can use BRTOOLS (newer version) or sapdba (old version)
 How does one change the default Oracle passwords?
Passwords for SYS/CHANGE_ON_INSTALL, SYSTEM/MANAGER, and SAPR3/SAP should be changed for security reasons.
The easiest way to change them is using the R3INST program. The only negative consequence when SYSTEM's password is changed is that sapdba will request a password to perform most actions.
You can use command 'sapdba -sapr3 <pwd>' to change the SAPR3 user password. This also updates the SAPUSER table entry. There is also a ommand
sapdba -alter_user <uid>/<pwd>
to change other Oracle user passwords.
 How does one monitor database space growth?
SAP/R3 ships complete with all tables needed for all modules. Whether or not the modules are being used determines whether certain tables will grow or not.
By modules, we mean applications - SD (Sales and Distribution), MM (Material Management), HR (Human Resources), FI (Financials), etc. All of these tables are initially created with 16K initial extent, 16K next extent.
The growth of 50GB a month shows that your site is probably using a lot of the modules (as one would expect with a properly used ERP app) or that there are many users with a lot of volume for a handful of modules.
Using the SAP transaction DB02, one can watch the growth of extents and tablespace allocations.