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https://issues.apache.org/jira/browse/CASSANDRA-981?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12869685#action_12869685
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Ryan King commented on CASSANDRA-981:
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>I think what we want to do is have the "dynamic" part just apply to
>endpoint-sorting, and leave replica determination up to the strategy in terms
>of DC + Rack.
I think this could be good for more than network distance, it would also help a
cluster route around a node that is slow (either permanently or temporarily).
In addition to being in compaction, a node that has just been restarted and
therefore has empty caches should be routed around (but not completely, since
it needs traffic in order to warm its caches).
> 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
> Fix For: 0.7
>
>
> 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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