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https://issues.apache.org/jira/browse/CASSANDRA-2034?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13080115#comment-13080115
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Patricio Echague commented on CASSANDRA-2034:
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{quote} return to the client normally after ConsistencyLevel is achieved, but
after RpcTimeout we check the responseHandler write acks and write local hints
for any missing targets {quote}
The way I'm planning on implementing this last part is by adding a
maybeWriteHint in the hook that already exist for the ExpiringMap in
MessagingService.
The only problem is that I don't have the mutation as to generate a hint in
MessageService.
I might catch what nodes hasn't replied in the StorageProxy and store one
mutation per node that hasn't replied into an ExpiringMap in MessagingService.
The down side is that for CL.ONE I will end up storing basically one mutation
per replica minus the one that responded, and it may lead to memory issues.
Thoughts?
> Make Read Repair unnecessary when Hinted Handoff is enabled
> -----------------------------------------------------------
>
> Key: CASSANDRA-2034
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2034
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Jonathan Ellis
> Assignee: Patricio Echague
> Fix For: 1.0
>
> Attachments: 2034-formatting.txt, CASSANDRA-2034-trunk-v2.patch,
> CASSANDRA-2034-trunk-v3.patch, CASSANDRA-2034-trunk-v4.patch,
> CASSANDRA-2034-trunk-v5.patch, CASSANDRA-2034-trunk-v6.patch,
> CASSANDRA-2034-trunk-v7.patch, CASSANDRA-2034-trunk.patch
>
> Original Estimate: 8h
> Remaining Estimate: 8h
>
> Currently, HH is purely an optimization -- if a machine goes down, enabling
> HH means RR/AES will have less work to do, but you can't disable RR entirely
> in most situations since HH doesn't kick in until the FailureDetector does.
> Let's add a scheduled task to the mutate path, such that we return to the
> client normally after ConsistencyLevel is achieved, but after RpcTimeout we
> check the responseHandler write acks and write local hints for any missing
> targets.
> This would making disabling RR when HH is enabled a much more reasonable
> option, which has a huge impact on read throughput.
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