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Jimmy Xiang commented on HIVE-9258: ----------------------------------- I checked the code and we do share the RSC. Ran several explain/ queries in a cluster. We just created one remote Spark driver. This means the RSC is indeed shared, right? > Explain query shouldn't launch a Spark application [Spark Branch] > ----------------------------------------------------------------- > > Key: HIVE-9258 > URL: https://issues.apache.org/jira/browse/HIVE-9258 > Project: Hive > Issue Type: Sub-task > Components: Spark > Reporter: Xuefu Zhang > Assignee: Jimmy Xiang > > Currently for Hive on Spark, query plan includes the number of reducers, > which is determined partly by the Spark cluster. Thus, explain query will > need to launch a Spark application (Spark remote context), which is costly. > To make things worse, the application is discarded right way. > Ideally, we shouldn't launch a Spark application even for an explain query. -- This message was sent by Atlassian JIRA (v6.3.4#6332)