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Robert Neumann commented on SPARK-650: -------------------------------------- Sean, I agree this is the essential question in this thread. If we get this sorted out, then we are good and can achieve consensus on what to do with this ticket. A singleton "works" indeed. However, from a software engineering point of view it is not nice. There exists a class of Spark Streaming jobs that requires "setup -> do -> cleanup" semantics. The framework (in this case Spark Streaming) should explicitly support these semantics through appropriate API hooks. A singleton instead would hide these semantics and you would need to implement some laxy code to check whether an HBase connection was already setup or not; the singelton would need to do this for every write operation to HBase. I do not think that application logic (the Singleton within the Spark Streaming job) is the right place to wire in the "setup -> do -> cleanup" pattern. It is a generic pattern and there exists a class of Spark Streaming jobs (not only one specific Streaming job) that are based on this pattern. > Add a "setup hook" API for running initialization code on each executor > ----------------------------------------------------------------------- > > Key: SPARK-650 > URL: https://issues.apache.org/jira/browse/SPARK-650 > Project: Spark > Issue Type: New Feature > Components: Spark Core > Reporter: Matei Zaharia > Priority: Minor > > Would be useful to configure things like reporting libraries -- This message was sent by Atlassian JIRA (v6.3.4#6332) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org