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Tommaso Teofili commented on LUCENE-8162: ----------------------------------------- the class in Oak is a fork of TMP, but the one in Lucene would extend TMP (see [https://gist.github.com/tteofili/f60bd633557b93be106dc8e806d2b8fa).] the logic uses doc/sec and mb/sec so you're right that the no. of _commits_ is not measured. {quote}So if I index at a high rate but don't commit, the throttling logic can still kick in? {quote} yes > Make it possible to throttle (Tiered)MergePolicy when commit rate is high > ------------------------------------------------------------------------- > > Key: LUCENE-8162 > URL: https://issues.apache.org/jira/browse/LUCENE-8162 > Project: Lucene - Core > Issue Type: Improvement > Components: core/index > Reporter: Tommaso Teofili > Priority: Major > Fix For: trunk > > > As discussed in a recent mailing list thread [1] and observed in a project > using Lucene (see OAK-5192 and OAK-6710), it is sometimes helpful to throttle > the aggressiveness of (Tiered)MergePolicy when commit rate is high. > In the case of Apache Jackrabbit Oak a dedicated {{MergePolicy}} was > implemented [2]. > That MP doesn't merge in case the number of segments is below a certain > threshold (e.g. 30) and commit rate (docs per sec and MB per sec) is high > (e.g. above 1000 doc / sec , 5MB / sec). > In such impl, the commit rate thresholds adapt to average commit rate by > means of single exponential smoothing. > The results in that specific case looked encouraging as it brought a 5% perf > improvement in querying and ~10% reduced IO. However Oak has some specifics > which might not fit in other scenarios. Anyway it could be interesting to see > how this behaves in plain Lucene scenario. > [1] : [http://markmail.org/message/re3ifmq2664bqfjk] > [2] : > [https://github.com/apache/jackrabbit-oak/blob/trunk/oak-lucene/src/main/java/org/apache/jackrabbit/oak/plugins/index/lucene/writer/CommitMitigatingTieredMergePolicy.java] -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org