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From "Jeremiah Jordan (JIRA)" <j...@apache.org>
Subject [jira] [Issue Comment Deleted] (CASSANDRA-7774) CqlRecordReader creates wrong cluster if the first replica of a split is down
Date Wed, 20 Aug 2014 15:28:26 GMT

     [ https://issues.apache.org/jira/browse/CASSANDRA-7774?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Jeremiah Jordan updated CASSANDRA-7774:
---------------------------------------

    Comment: was deleted

(was: So the LimitedLocalNodeFirstLocalBalancingPolicy doesn't work right?  If thats true
we should fix that I think, not make a new policy?  As spark and other things are using LimitedLocalNodeFirstLocalBalancingPolicy.)

> CqlRecordReader creates wrong cluster if the first replica of a split is down
> -----------------------------------------------------------------------------
>
>                 Key: CASSANDRA-7774
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-7774
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Hadoop
>            Reporter: Jacek Lewandowski
>            Assignee: Jacek Lewandowski
>         Attachments: 0001-CASSANDRA-7774-Fixed-cluster-initialisation-for-a-sp.patch,
CASSANDRA-7774-patch-v2.patch
>
>
> For a given split, {{CqlRecordReader}} gets a list of replicas of that split. Then, it
tries to create a Cluster object with a ClusterBuilder for each replica separately in a loop,
so that if the cluster creation fails for a certain replica, the next replica is tried. Unfortunately
it does not work, because the cluster creation does not fail if the provided contact point
is down. So, it always selects the first replica regardless of its state.
> The solution is quite simple - {{ClusterBuilder}} accepts a collection of contact points
- at least one of them must be up. So instead of iterating over the replicas we can pass the
whole set of them and the driver will select the working one. It will follow some changes
in the load balancing policy - I'm going to switch to use -the same- similar balancing policy
-as- to the one we use in OSS Spark Connector.



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