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https://issues.apache.org/jira/browse/SOLR-8241?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15517433#comment-15517433
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Ben Manes commented on SOLR-8241:
---------------------------------

Can you explain why a new instance is required and the entire cache swapped?

There is an open issue for supporting bulk refresh, but its been low on my list 
of priorities. Not sure if that would have worked for this rewarming process.

> 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



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