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https://issues.apache.org/jira/browse/CASSANDRA-7774?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jacek Lewandowski updated CASSANDRA-7774:
-----------------------------------------
Description:
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.
was:
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 balancing policy as we use in OSS Spark
Connector.
> 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
>
>
> 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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