How to resolve “ERROR XSLA7: Cannot redo operation null in the log” error?

Subject 
How to resolve a Derby startup issue due to DB files corruption?

Description
You may run into the following error message when using Artifactory's default database - Derby, while the allocated DB disk space partition runs out.

ERROR XSLA7: Cannot redo operation null in the log.

Caused by: ERROR XSLAO: Recovery failed unexpected problem: Log record is Not first but transaction is not in transaction table : 186807691.

The error above indicates a failure starting Derby DB when the allocated disk space runs out. There is a tendency to delete files that we no longer need, however, this is not the recommended solution in this case. When the disk space is full of new files which cannot be written, existing files are being corrupted - which means that files or parts of the file that the system expected are not written properly or there are files of actions that have not been completed yet, therefore, the DB was not able to start since it was not synced properly.

Resolution

1. Stop Artifactory service 
2. Move/backup the actual content of the Derby DB logs folder to a different location ($ARTIFACTORY_HOME/derby/logs) with enough allocated disk space ((i.e you may move it to the Desktop)
3. Start Artifactory service