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https://issues.apache.org/jira/browse/KAFKA-8020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16782531#comment-16782531
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Richard Yu commented on KAFKA-8020:
-----------------------------------
For optimal insertion times, we would probably use hierarchical time wheels
which is used in Kafka requests (purgatory). It would be faster than using a
priority queue and could be created on demand.
> Consider making ThreadCache a time-aware LRU Cache
> --------------------------------------------------
>
> Key: KAFKA-8020
> URL: https://issues.apache.org/jira/browse/KAFKA-8020
> Project: Kafka
> Issue Type: Improvement
> Components: streams
> Reporter: Richard Yu
> Priority: Major
>
> In distributed systems, time-aware LRU Caches offers a superior eviction
> policy better than traditional LRU models, having more cache hits than
> misses. In this new policy, if an item is stored beyond its useful lifespan,
> then it is removed. For example, in {{CachingWindowStore}}, a window usually
> is of limited size. After it expires, it would no longer be queried for, but
> it potentially could stay in the ThreadCache for an unnecessary amount of
> time if it is not evicted (i.e. the number of entries being inserted is few).
> For better allocation of memory, it would be better if we implement a
> time-aware LRU Cache which takes into account the lifespan of an entry and
> removes it once it has expired.
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