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From Nate McCall <>
Subject Re: ONE has much higher latency than LOCAL_ONE
Date Wed, 22 Mar 2017 00:11:57 GMT
On Wed, Mar 22, 2017 at 12:48 PM, Shannon Carey <> wrote:
> The cluster is in two DCs, and yes the client is deployed locally to each

First off, what is the goal of using ONE instead of LOCAL_ONE? If it's
failover, this could be addressed with a RetryPolicy starting wth LOCAL_ONE
and falling back to ONE.

Are you using the ".withLocalDc" option in the DCAwareRoundRobinPolicy
builder? (It's been a while since I've gone through this in detail,
though). If you could provide a snippet that included the complete options
passed to the builder that might be helpful.

Also, check for the complete forms of these two logging messages on the app
side during startup (the second one is at INFO so adjust if needed):
"Some contact points don't match local data center. Local DC = {}.
Non-conforming contact points: {}"
"Using data-center name '{}' for DCAwareRoundRobinPolicy..."

Make sure those line up with the cluster topology and your expectations.

Actually, in typing that up, it may be more appropriate to move the
conversation over here since this is probably driver specific:!forum/java-driver-user

Nate McCall
Wellington, NZ

Apache Cassandra Consulting

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