LUCENE-10574: Avoid O(n^2) merging with LogMergePolicy#936
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jpountz merged 8 commits intoapache:mainfrom Jun 3, 2022
Merged
LUCENE-10574: Avoid O(n^2) merging with LogMergePolicy#936jpountz merged 8 commits intoapache:mainfrom
jpountz merged 8 commits intoapache:mainfrom
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jpountz
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May 31, 2022
| } else { | ||
| newInfos.add(info); | ||
| } | ||
| } |
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this change maintains order of merged segments in segment infos, akin to SegmentInfos#applyMergeChanges, which is important for LogMergePolicy
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Originally I had tried to remove O(n^2) merging from LogMergePolicy using the
same approach as for TieredMergePolicy, but this did not work well as it fought
against invariants that LogMergePolicy is trying to maintain. So this switches
to a completely different approach that is more in line with the existing logir
of LogMergePolicy: instead of being rounded to the floor segment size, segments
below the floor segment size get applied a greater level span that allows more
unbalanced merges on smaller segments but still requires them to be somewhat
balanced.