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Ben Manes commented on SOLR-8241: --------------------------------- Thanks for the information. I definitely meant that would be a new issue if we were happy with the results here. It makes sense that Lucene wouldn't want dependencies and a different expert would be needed to review. As those are synchronous I can easily port the code over (its the concurrency that's hard). We'll revisit that if we have a positive experience here, as I think this is the more critical cache for Solr. Thanks a lot Shawn for pushing this forward and all your help thus far. > Evaluate W-TinyLfu cache > ------------------------ > > Key: SOLR-8241 > URL: https://issues.apache.org/jira/browse/SOLR-8241 > Project: Solr > Issue Type: Wish > Components: search > Reporter: Ben Manes > Priority: Minor > Attachments: SOLR-8241.patch > > > SOLR-2906 introduced an LFU cache and in-progress SOLR-3393 makes it O(1). > The discussions seem to indicate that the higher hit rate (vs LRU) is offset > by the slower performance of the implementation. An original goal appeared to > be to introduce ARC, a patented algorithm that uses ghost entries to retain > history information. > My analysis of Window TinyLfu indicates that it may be a better option. It > uses a frequency sketch to compactly estimate an entry's popularity. It uses > LRU to capture recency and operate in O(1) time. When using available > academic traces the policy provides a near optimal hit rate regardless of the > workload. > I'm getting ready to release the policy in Caffeine, which Solr already has a > dependency on. But, the code is fairly straightforward and a port into Solr's > caches instead is a pragmatic alternative. More interesting is what the > impact would be in Solr's workloads and feedback on the policy's design. > https://github.com/ben-manes/caffeine/wiki/Efficiency -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org For additional commands, e-mail: dev-h...@lucene.apache.org