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ASF GitHub Bot commented on KAFKA-5932: --------------------------------------- Github user asfgit closed the pull request at: https://github.com/apache/kafka/pull/3978 > Avoid call fetchPrevious in FlushListeners > ------------------------------------------ > > Key: KAFKA-5932 > URL: https://issues.apache.org/jira/browse/KAFKA-5932 > Project: Kafka > Issue Type: Improvement > Components: streams > Reporter: Guozhang Wang > Assignee: Bill Bejeck > Fix For: 1.0.0 > > > When caching is turned on for a window or session store, upon {{store.put()}} > the cache may gets flushed, trigger the dirty flush listener calling > {{maybeForward()}}, which calls {{fetchPrevious()}}. > Unfortunately {{fetchPrevious()}} could be a very expensive call to make, and > sometimes are not necessary: > 1. When {{KStreamWindowAggregate.process()}} already gets the previous value > when aggregating, so we could passing the old value through the tuple > forwarder without calling fetchPrevious again. > 2. When we know that {{sendOldValues}} flag is turned off. -- This message was sent by Atlassian JIRA (v6.4.14#64029)