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Sylvain Lebresne commented on CASSANDRA-2890:
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bq. How necessary is this if we change SSnitch to match ANTS?
That would restore what I though was the previous behavior, i.e, for equal
score the first alive replica in ring order will be picked. Which means that
provided the ring is well balanced and the client query are well balanced too,
the load will be uniform. But that suppose that
# client queries are well balanced. True, this is already a requirement to
get the best out of your cluster. But it would make it a much stronger
requirement as more would depend on it.
# this is for when the dynamic snitch returns equal scores. I think that is
actually the stronger motivation for this: relying on the scores of the dynamic
snitch when those scores are not influenced by the operation we're doing is
likely a bad idea. Clusters that have a very low read rate (compared to the
write one) will likely still experience poor load balancing.
> Randomize (to some extend) the choice of the first replica for counter
> increment
> --------------------------------------------------------------------------------
>
> Key: CASSANDRA-2890
> URL: https://issues.apache.org/jira/browse/CASSANDRA-2890
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Affects Versions: 0.8.0
> Reporter: Sylvain Lebresne
> Assignee: Sylvain Lebresne
> Priority: Minor
> Labels: counters
> Fix For: 0.8.6
>
> Attachments: 2890.patch
>
>
> Right now, we choose the first replica for a counter increments based solely
> on what the snitch returns. If the clients requests are well balanced over
> the cluster and the snitch not ill configured, this should not be a problem,
> but this is probably too strong an assumption to make.
> The goal of this ticket is to change this to choose a random replica in the
> current data center instead.
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