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https://issues.apache.org/jira/browse/LUCENE-10196?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17437861#comment-17437861
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Adrien Grand commented on LUCENE-10196:
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[~broustant] Do you know if i similar improvement can be made to IntroSelector? 
IntroSelector is one of the bottlenecks of this benchmark: 
[http://people.apache.org/~mikemccand/geobench.html#search-polyRussia|http://people.apache.org/~mikemccand/geobench.html#search-polyRussia.],
 which spends significant time converting the Russia polygon into a 
ComponentTree (see ComponentTree#createTree).

> Improve IntroSorter with 3-ways partitioning
> --------------------------------------------
>
>                 Key: LUCENE-10196
>                 URL: https://issues.apache.org/jira/browse/LUCENE-10196
>             Project: Lucene - Core
>          Issue Type: Improvement
>            Reporter: Bruno Roustant
>            Priority: Major
>             Fix For: 8.11
>
>          Time Spent: 2h 20m
>  Remaining Estimate: 0h
>
> I added a SorterBenchmark to evaluate the performance of the various Sorter 
> implementations depending on the strategies defined in BaseSortTestCase 
> (random, random-low-cardinality, ascending, descending, etc).
> By changing the implementation of the IntroSorter to use a 3-ways 
> partitioning, we can gain a significant performance improvement when sorting 
> low-cardinality lists, and with additional changes we can also improve the 
> performance for all the strategies.
> Proposed changes:
>  - Sort small ranges with insertion sort (instead of binary sort).
>  - Select the quick sort pivot with medians.
>  - Partition with the fast Bentley-McIlroy 3-ways partitioning algorithm.
>  - Replace the tail recursion by a loop.



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