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Yin Huai updated SPARK-2176: ---------------------------- Summary: Extra unnecessary exchange operator in the result of an explain command (was: Extra unnecessary exchange operator in the result of a explain command) > Extra unnecessary exchange operator in the result of an explain command > ----------------------------------------------------------------------- > > Key: SPARK-2176 > URL: https://issues.apache.org/jira/browse/SPARK-2176 > Project: Spark > Issue Type: Bug > Components: SQL > Reporter: Reynold Xin > Assignee: Yin Huai > > {code} > hql("explain select * from src group by key").collect().foreach(println) > [ExplainCommand [plan#27:0]] > [ Aggregate false, [key#25], [key#25,value#26]] > [ Exchange (HashPartitioning [key#25:0], 200)] > [ Exchange (HashPartitioning [key#25:0], 200)] > [ Aggregate true, [key#25], [key#25]] > [ HiveTableScan [key#25,value#26], (MetastoreRelation default, src, > None), None] > {code} > There are two exchange operators. > However, if we do not use explain... > {code} > hql("select * from src group by key") > res4: org.apache.spark.sql.SchemaRDD = > SchemaRDD[8] at RDD at SchemaRDD.scala:100 > == Query Plan == > Aggregate false, [key#8], [key#8,value#9] > Exchange (HashPartitioning [key#8:0], 200) > Aggregate true, [key#8], [key#8] > HiveTableScan [key#8,value#9], (MetastoreRelation default, src, None), None > {code} > The plan is fine. -- This message was sent by Atlassian JIRA (v6.2#6252)