The Oracle Counters for Windows Performance Monitor package is not installed by default. In order to install them when you install Oracle, select the custom install option. You can also install this option later via the Oracle installer. Once Oracle Counters for Windows Performance Monitor has been installed, you must perform one more piece of setup. The Oracle performance counters are set up to monitor one Oracle instance. Information about this instance must be configured in the registry. In order to do this, from a command prompt run orafcfg.exe with a username, password and Oracle net service name as follows:
operfcfg –U system –P password –D sid
This will update the registry. You should now be able to monitor Oracle via perfmon. Some of the things that you can monitor are:
- The Oracle Buffer Cache. Here you can see the cache miss ratio.
- Shared Pool Stats. This collection includes the data dictionary cache, and the library
cache. - Log Buffer. Provides information on log space requests.
- Database Data Files. This object provides physical read and write per second counters.
- DBWR stats. Provides information on the DB Writer processes.
Miscellaneous. Other statistics include dynamic space management, free lists and dynamic sorts.
By taking advantage of Oracle Counters for Windows Performance Monitor you can easily and efficiently monitor Oracle along with monitoring the OS. Some of the most important and first counters that I look at when performance monitoring a system are:
- Processor: %Processor Time. This gives me a quick look at how busy the system is.
- Physical Disk: Avg. Disk sec/Read, Avg. Disk sec/Write. This provides me with an overview of how well the I/O subsystem is doing.
When first looking at a system I am actually more interested in disk latencies than throughput. The Avg. Disk sec/Read and Avg. Disk sec/Write should be in the range of 5-15 ms (0.005 – 0.015). Anything higher than this indicates a problem.
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