Low performance on deleting plan branches (big AUDIT_LOG table)

Problem Definition

When a plan is deleted Bamboo also removes all related audit log entries from AUDIT_LOG table. This task might have a high cost in Bamboo instances with a big AUDIT_LOG table. To complicate things a little bit, the JOB_KEY column is used for the search and this column is not indexed.

Suggested Solution

• Add an index to the JOB_KEY column to increase the search speed on finding elements to be removed
  or even better
• Avoid removing history from audit logs. If they are there to track what happened in the server, what is the purpose of removing history form old plans? Maybe to avoid confusion if a new plan is created with the same plan key? But than in this case we would see an event of plan deletion and another for plan creation.
  We might need to implement a way to expire really old audit logs or even move the complete information to syslog: [BAM-20024] Bamboo syslog integration

Workaround

Reduce the size of the AUDIT_LOG table by removing really old history or even dumping the table to a file that can be used in case old history is needed.