Alex Parvulescu created OAK-4812:
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Summary: Reduce calls to SegmentStore#newSegmentId from the
Segment class
Key: OAK-4812
URL: https://issues.apache.org/jira/browse/OAK-4812
Project: Jackrabbit Oak
Issue Type: Improvement
Components: segment-tar
Reporter: Alex Parvulescu
Priority: Minor
OAK-4631 introduced a change in records handling in a segment that will amplify
the number of calls to {{SegmentStore#newSegmentId}} by the number of external
references [0]. It usually is the case that there are a lot of record
references that point to the same segment id, and the existing
{{recordIdCache}} would not help much in this case.
The scenario I'm seeing for offline compaction (might be a bit biased) is a
full traversal of segments that increases pressure on the {{SegmentIdTable}} by
calling {{newSegmentId}} with a lot of already existing segments.
I'm creating this issue as an 'Improvement' as I think it is interesting to
look into reducing this pressure. This might be by squeezing more out of the
{{SegmentIdTable}} bits (I'd like to followup on this with a benchmark) or
revisiting the code paths from the {{Segment}} class.
[0]
https://github.com/apache/jackrabbit-oak/blob/trunk/oak-segment-tar/src/main/java/org/apache/jackrabbit/oak/segment/Segment.java#L405
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