Doctor in the database
What is also important is that the database home page shows the latest ADDM findings. This is a proactive diagnostics engine that runs every hour by default on the database, and generates a list of recommendations.
Clicking on the ADDM Findings button takes you to the last ADDM Performance Analysis page, which is displayed in the following screenshot:
Informational findings are also shown. ADDM lets you know if the database is CPU-bound or I/O-bound, it lets you know of hard/soft parse issues, top SQL statements impacting the database, any locking issues, and so on.
ADDM is also RAC aware and informs you if there are any networking/interconnect or database configuration issues affecting the performance of the RAC database. For example, improper database sequence usage can have a severe performance impact on such active/active databases.
You can run ADDM at any time by going to Performance | Advisors Home on the menu and then selecting ADDM from the list of advisors available. When you run ADDM in this way, you can analyze the current database situation or use past performance data to tell you what went wrong in the past.
You can drill down further into any of the findings. For example, if you click on the Soft Parse finding on the previous page (shown in the preceding screenshot), ADDM displays the possible recommendations on how to fix this performance issue, such as by increasing the value of the session_cached_cursors
parameter to increase the session cursor cache size and even allows you to action it on the spot by clicking on the Implement button: