如何使用spark-cassandra-connector实现LEFT或RIGHT JOIN [英] How implement LEFT or RIGHT JOIN using spark-cassandra-connector

问题描述

我有火花工作.我正在使用Cassandra作为数据存储. 我有需要与cassandra表一起加入的流. 我正在使用spark-cassandra-connector，有一个很棒的方法 joinWithCassandraTable ，据我所知，用cassandra表实现内部联接

I have spark streaming job. I am using Cassandra as datastore. I have stream which is need to be joined with cassandra table. I am using spark-cassandra-connector, there is great method joinWithCassandraTable which is as far as I can understand implementing inner join with cassandra table

val source: DStream[...] = ...
source.foreachRDD { rdd =>
  rdd.joinWithCassandraTable( "keyspace", "table" ).map{ ...
  }
}

所以问题是如何用cassandra表实现左外部联接?

So the question is how can I implement left outer join with cassandra table?

预先感谢

推荐答案

当前不支持此功能，但是有介绍该功能的票证.如果您希望将来引入它，请对其进行投票.

This is currently not supported, but there is a ticket to introduce the functionality. Please vote on it if you would like it introduced in the future.

https://datastax-oss.atlassian.net/browse/SPARKC-181

故障单中建议一种解决方法

A workaround is suggested in the ticket

这篇关于如何使用spark-cassandra-connector实现LEFT或RIGHT JOIN的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！