Performing an Oracle database health check? We have a little list

Guidelines for the diligent DBA

  • alert
  • submit to reddit

Mine the logs

Check for errors in the logs. Some of these errors may be worrisome and critical, and should be addressed immediately, while there are others that are not as significant. It is important to be able to recognize the difference and correct them.

Critical errors also create incidents and incident dumps in the Automatic Diagnostic Repository (ADR), which is the system-wide tracing and logging repository.

Each Oracle database server writes to a trace file. When a server process detects an error, information about it is sent to that trace file. The name of each trace file usually includes the name of the process writing the file, such as the RECO recovery process, for example.

The alert log is available in XML or text. This includes a list of all messages and errors, including internal errors (ORA-600), errors relating to block corruption (ORA-1578), and deadlock-based errors (ORA-60).

The alert log also offers several categories of error message relating to shared server functions and dispatcher processes, and will tell you about errors that happen during the automatic refresh of a materialized view.

One particular class of error message to watch out for is background processes. These should be addressed right away. If you get a message written to the LGWR trace file and the alert log, explaining that the log writer process (LGWR) cannot write to a member of a log group, then that's a sign of a media or I/O problem.


Checking the performance of the database is a key part of any Oracle health check. Toad lets you check for specific parameters, including the distribution of datafiles across I/O channels (which can help to prevent data bottlenecks). It can also monitor usage of the shared pool, which is the area of memory that Oracle uses hold its library cache. This acts as a buffer for all SQL statements that are processed by the Oracle database, so performance will suffer if this is overly contended.

Toad also lets you compare your current health check against checks made before, to see what has changed. So if critical performance parameters (or others) are changing, you can see that clearly.


Ask for and solicit feedback. Listen to users of the database, and take notes. The best health check for the database is to find out how it's affecting people in real life. What are they complaining about? What errors are they getting and what frustrations do they have? Define steps to mitigate these complaints, if you haven't already.

Script it

Automation is the foundation for any good DBA, especially in areas such as health checks, which should be repeated on a regular basis so that you can spot any emerging problems.

You can also script Toad's entire health check automatically, by using the small camera icon at the bottom left of the health check window to save the settings in that area. It will then be created as an application of its own inside Toad Automation Designer, enabling you to run it regularly and quickly. You can get it sent to your email, if you like, so that you can be alerted to any potential database difficulties over your morning bagel.

No one step will be enough to keep your database in tip-top shape. Instead, any health check should encompass all of these steps, providing good visibility across all facets of its operation. Following these guidelines will help the diligent DBA to spot any bottlenecks for their applications as they appear, and help to ensure stability going forward. Doing it on a regular databases will help prevent your datafile from becoming a datafail. ®

The Register is running a series of Oracle DBA workshop articles in association with Dell Software. Interested in learning more? Check out these Dell whitepapers.

More from The Register

next story
Preview redux: Microsoft ships new Windows 10 build with 7,000 changes
Latest bleeding-edge bits borrow Action Center from Windows Phone
Google opens Inbox – email for people too thick to handle email
Print this article out and give it to someone tech-y if you get stuck
Microsoft promises Windows 10 will mean two-factor auth for all
Sneak peek at security features Redmond's baking into new OS
UNIX greybeards threaten Debian fork over systemd plan
'Veteran Unix Admins' fear desktop emphasis is betraying open source
Entity Framework goes 'code first' as Microsoft pulls visual design tool
Visual Studio database diagramming's out the window
Google+ goes TITSUP. But WHO knew? How long? Anyone ... Hello ...
Wobbly Gmail, Contacts, Calendar on the other hand ...
DEATH by PowerPoint: Microsoft warns of 0-day attack hidden in slides
Might put out patch in update, might chuck it out sooner
Ubuntu 14.10 tries pulling a Steve Ballmer on cloudy offerings
Oi, Windows, centOS and openSUSE – behave, we're all friends here
prev story


Choosing cloud Backup services
Demystify how you can address your data protection needs in your small- to medium-sized business and select the best online backup service to meet your needs.
Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Storage capacity and performance optimization at Mizuno USA
Mizuno USA turn to Tegile storage technology to solve both their SAN and backup issues.