How to peek into the alert.log file?

Following up on extended SQL and CBO trace retrieval you can also retrieve the alert.log file from a database through Mumbai if you have installed the Mumbai42 schema into the database as explained in my previous blog post.

As you can see in the image above, you can retrieve just the last 2000 lines, the complete alert.log file or you can load an alert.log file from the local file system if you have copied it over from the database server manually.

Once the alert.log is loaded, the filter option as seen in the image above comes in handy to find just the errors, referenced trace files and/or DB/system changes. Filtering on “Parameter” will show only the parameters that are emitted into the alert.log file after an instance restart, so you can quickly check how the parameters changed over time.

For references to trace files in the alert.log file, you can right-click on the reference and select “Open referenced file” to fetch the trace file from the database server and open it in Mumbai.