Providing a history of changes to your Oracle database parameters is not only a DBA best practice, it is absolutely required in a mission-critical production environment. Back when Oracle parameters were kept in a flat file on the server (the init.ora file) tracking changes was difficult.
However, once Oracle introduced the "spfile" feature it became easier to track changes to initialization parameters. Below are two common techniques for tracking Oracle initialization parameters:
- auditing, and
- using the extra-cost AWR method.
If you have purchased the extra cost performance pack and diagnostic pack (and have access to the AWR dba_hist_parameter table), it is easy to run a script to track all changes to your initialization parameters.