When database administrators work on a Data Guard problem or plan an important Data Guard operation such as role transition, they generally prefer to gather comprehensive trace information about the activity of Data Guard-related processes. For this purpose, Oracle offers the LOG_ARCHIVE_TRACE parameter. By setting this parameter to an appropriate value, it's possible to have detailed information about log archiving, redo transport, and Redo Apply activities.

The default value of this initialization parameter is 0, which means the additional tracing feature is off, and Oracle will continue generating its default alert and trace entries related to error conditions. It's possible to change the value of this parameter in the primary and/or standby databases online using the ALTER SYSTEM statement. For example, look at the following statement:

SQL> ALTER SYSTEM SET LOG_ARCHIVE_TRACE=15; 

In the Real Application Cluster database it's possible to set different tracing levels for different instances, if necessary.

The following table shows the values and meanings of the LOG_ARCHIVE_TRACE parameter levels. It's also possible to turn on tracing for multiple levels. For this purpose, set the parameter to the sum of the intended levels. For example, if we want comprehensive tracing for real-time apply activity and LGWR redo shipping network activity, which are level 4096 and 512 respectively, we can set the LOG_ARCHIVE_TRACE parameter to 4608.