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https://issues.apache.org/jira/browse/CASSANDRA-2034?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13085858#comment-13085858
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Patricio Echague commented on CASSANDRA-2034:
---------------------------------------------
Thanks Jonathan for the snippet of code. I didn't notice it was broken.
I don't see where CallbackInfo.shouldHint is broken.
{code}
public boolean shouldHint()
{
if (StorageProxy.shouldHint(target) && isMutation)
{
try
{
1) ((IWriteResponseHandler) callback).get();
return true;
}
catch (TimeoutException e)
{
// CL was not achieved. We should not hint.
}
}
return false;
}
{code}
I process the callback after the message expired. If the CL was achieved (and
the requirement for a hint are gathered) I return true for this target meaning
that a hint needs to be written.
On the other hand, if the message expire and the CL was not achieved, then I
return FALSE (for this target).
Perhaps it needs a special treatment during the shutdown ?
> 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-v10.patch,
> CASSANDRA-2034-trunk-v11.patch, CASSANDRA-2034-trunk-v11.patch,
> CASSANDRA-2034-trunk-v12.patch, CASSANDRA-2034-trunk-v13.patch,
> CASSANDRA-2034-trunk-v14.patch, 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-v8.patch,
> CASSANDRA-2034-trunk-v9.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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