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https://issues.apache.org/jira/browse/CASSANDRA-981?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12914377#action_12914377
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Wouter de Bie commented on CASSANDRA-981:
-----------------------------------------
This stuff is actually more broken than I thought..
It only works with one keyspace, since the DynamicEndpointSnitchMBean is
registered per keyspace, which is not allowed.
Next, the DynamicEndpointSnitch doesn't work with the RackAwareStrategy, since
that one checks the following:
{noformat}
if (!(snitch instanceof EndPointSnitch))
throw new IllegalArgumentException(("RackAwareStrategy requires
EndPointSnitch."));
{noformat}
And breaks, since the DynamicEndPointSnitch extends AbstractEndpointSnitch and
not EndPointSnitch. RackAwareStrategy should check for the interface
IEndPointSnitch.
> Dynamic endpoint snitch
> -----------------------
>
> Key: CASSANDRA-981
> URL: https://issues.apache.org/jira/browse/CASSANDRA-981
> Project: Cassandra
> Issue Type: New Feature
> Components: Core
> Reporter: Jonathan Ellis
> Assignee: Brandon Williams
> Fix For: 0.6.5
>
> Attachments: 981-0.6.txt, 981-fix-v2.txt, 981-fix.txt, 981.txt
>
>
> An endpoint snitch that automatically and dynamically infers "distance" to
> other machines without having to explicitly configure rack and datacenter
> positions solves two problems:
> The killer feature here is adapting to things like compaction or a
> failing-but-not-yet-dead disk. This is important, since when we are doing
> reads we pick the "closest" replica for actually reading data from (and only
> read md5s from other replicas). This means that if the closest replica by
> network topology is temporarily slow due to compaction (for instance), we'll
> have to block for its reply even if we get the other replies much much faster.
> Not having to manually re-sync your configuration with your network topology
> when changes (adding machines) are made is a nice bonus.
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