[OAK-6601] SegmentWriteOperation.isOldGeneration() too eager

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.7.7, 1.8.0
• Component/s: segment-tar
• Labels: compaction gc
• Assignee: Michael Dürig
• Reporter: Michael Dürig
• Created: 31/Aug/17 07:00
• Updated: 14/Sep/17 13:02
• Resolved: 31/Aug/17 09:27

Description

The SegmentWriteOperation.isOldGeneration() predicate includes some segments that are not "old". This leads to more deferred compaction operations than strictly necessary. The affected segments are those generated by tail compaction. Tail compaction created segments should only be included in the predicate once they are from another full compaction operation. Otherwise referencing such segments is fine as they will not be reclaimed in a cleanup following a tail compaction.