You are viewing a plain text version of this content. The canonical link for it is here.

Posted to jira@kafka.apache.org by "Richard Yu (JIRA)" <ji...@apache.org> on 2019/03/02 21:19:00 UTC

[jira] [Commented] (KAFKA-8020) Consider making ThreadCache a time-aware LRU Cache

    [ https://issues.apache.org/jira/browse/KAFKA-8020?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16782531#comment-16782531 ] 

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.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)