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https://issues.apache.org/jira/browse/HDFS-15291?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Konstantin Shvachko updated HDFS-15291:
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Description:
RPC queue is currently based on {{LinkedBlockingQueue}}, which is FIFO.
For Observer we delay execution of a call if its lastSeenStateId is larger than
the stateId of the Observer. The delay implemented as re-queuing the call to
the end of the queue. Re-queue is not atomic. We can avoid moving elements in
the queue by replacing {{LinkedBlockingQueue}} with a
{{CyclicalBlockingQueue}}. So that instead of re-queuing we just move the head
of the queue and the call automatically becomes the last.
was:
RPC queue is currently based on {{LinkedBlockingQueue}}, which is FIFO.
For Observer we delay execution of a call if its lastSeenStateId is larger than
the stateId of the Observer. The delay implemented as re-queuing the call to
the and of the queue. Re-queue is not atomic. We can avoid moving elements in
the queue by replacing {{LinkedBlockingQueue}} with a
{{CyclicalBlockingQueue}}. So that instead of re-queuing we just move the head
of the queue and the call automatically becomes the last.
> [SBN read] Implement CyclicalBlockingQueue to avoid requing RPC calls on
> Observer.
> ----------------------------------------------------------------------------------
>
> Key: HDFS-15291
> URL: https://issues.apache.org/jira/browse/HDFS-15291
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: namenode
> Reporter: Konstantin Shvachko
> Priority: Major
>
> RPC queue is currently based on {{LinkedBlockingQueue}}, which is FIFO.
> For Observer we delay execution of a call if its lastSeenStateId is larger
> than the stateId of the Observer. The delay implemented as re-queuing the
> call to the end of the queue. Re-queue is not atomic. We can avoid moving
> elements in the queue by replacing {{LinkedBlockingQueue}} with a
> {{CyclicalBlockingQueue}}. So that instead of re-queuing we just move the
> head of the queue and the call automatically becomes the last.
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