[OAK-2849] Improve revision gc on SegmentMK

• Type: Epic
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.5.13, 1.6.0
• Component/s: segment-tar
• Labels: compaction gc
• Epic Name: SegmentMK revision GC
• Assignee: Michael Dürig
• Reporter: Michael Dürig
• Created: 07/May/15 10:40
• Updated: 19/Jan/18 14:19
• Resolved: 03/Nov/16 13:45

Description

This is a container issue for the ongoing effort to improve revision gc of the SegmentMK.

I'm exploring

• ways to make the reference graph as exact as possible and necessary: it should not contain segments that are not referenceable any more and but must contain all segments that are referenceable.
• ways to segregate the reference graph reducing dependencies between certain set of segments as much as possible.
• Reducing the number of in memory references and their impact on gc as much as possible.

Issue Links

• is related to: OAK-4054 FileStore.containsSegment returns alway true (almost)
• is related to: OAK-2498 Root record references provide too little context for parsing a segment
• is related to: OAK-4011 Set online compaction default to paused
• is related to: OAK-4255 CLONE - FileStore.containsSegment returns alway true (almost)
• is related to: OAK-3485 FileStoreIT cleanup after tests
• relates to: OAK-3481 CompactionMapTest does not close file store
• relates to: OAK-3315 SegmentMk shouldn't store binary segments in the cache
• relates to: OAK-3309 Segment Tar SegmentCache loader stats
• relates to: OAK-3797 SegmentTracker#collectBlobReferences should retain fewer SegmentId instances
• relates to: OAK-2408 Investigate ways to make revision gc more precise