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https://issues.apache.org/jira/browse/STORM-3339?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yuzhao Chen reassigned STORM-3339:
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Assignee: Yuzhao Chen
> Port all the AtomicReference to ConcurrentHashMap for Nimbus
> ------------------------------------------------------------
>
> Key: STORM-3339
> URL: https://issues.apache.org/jira/browse/STORM-3339
> Project: Apache Storm
> Issue Type: Improvement
> Components: storm-core
> Affects Versions: 2.0.0
> Reporter: Yuzhao Chen
> Assignee: Yuzhao Chen
> Priority: Major
> Fix For: 2.0.0
>
>
> Now for many concurrent access resource in Nimbus.java, we use
> AtomicReference to make them multi thread safe. The resources summarized
> below:
> 1. heartbeatsCache
> 2. schedulingStartTimeNs
> 3. idToSchedStatus
> 4. nodeIdToResources
> 5. idToWorkerResources
> 6. idToExecutors
> The 1, 4, 5 and 6 may grows huge if we have hundreds of topologies on
> cluster, when we update AtomicReference, actually we passed in a Function and
> use compareAndSet to update the whole val to the new returned by the
> Function, in that case, we must do a reference copy and merge the changes,
> which seems not necessary.
> I think the reason to use AtomicReference is a legacy from old Clojure code,
> we can replace them totally with ConcurrentHashMap which supported better
> performance.
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