[OAK-9601] Refine logging to help detect dangling previous document pointers

• Type: Task
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 1.40.0
• Fix Version/s: 1.42.0
• Component/s: documentmk
• Assignee: Stefan Egli
• Reporter: Stefan Egli
• Created: 19/Oct/21 12:35
• Updated: 12/Jan/22 13:44
• Resolved: 20/Oct/21 09:58

Description

The log warns similar to the below pattern occur rather regularly:

org.apache.jackrabbit.oak.plugins.document.NodeDocument Document with previous revisions not found: 3:p/:async/r1795b3e463c-0-2/0

While the root cause is not yet clear, it is likely that this is "only a dangling pointer".

There were previous cases where something similar occurred: OAK-2377 (also see the referenced OAK-1791)

In fact, in OAK-2377 the log has been lowered to debug but in the remaining 2 cases it is still at warn: NodeDocument.getPreviousDoc and getPreviousDocs.

This ticket here is about 2 things:

• lowering the frequency of logging that warn, since it can flood log files if it applies to a frequently read document
• add some more details to a suspect root cause for further analysis.

Issue Links

• is related to: OAK-2377 Change log level in PropertyHistory
• is related to: OAK-1791 Clean up dangling references to previous documents
• links to: GitHub Pull Request #394