[jira] [Created] (SPARK-18642) Spark SQL: Catalyst is scanning undesired columns

["Mohit (JIRA)" <ji...@apache.org>]

Mohit created SPARK-18642:
-----------------------------

             Summary: Spark SQL: Catalyst is scanning undesired columns
                 Key: SPARK-18642
                 URL: https://issues.apache.org/jira/browse/SPARK-18642
             Project: Spark
          Issue Type: Bug
          Components: SQL
    Affects Versions: 1.6.2
         Environment: Ubuntu 14.04
Spark: Local Mode
            Reporter: Mohit


When doing a left-join between two tables, say A and B,  Catalyst has information about the projection required for table B. 

Code snippet below explains the scenario:

scala> val dfA = sqlContext.read.parquet("/home/mohit/ruleA")
dfA: org.apache.spark.sql.DataFrame = [aid: int, aVal: string]

scala> val dfB = sqlContext.read.parquet("/home/mohit/ruleB")
dfB: org.apache.spark.sql.DataFrame = [bid: int, bVal: string]

scala> dfA.registerTempTable("A")
scala> dfB.registerTempTable("B")

scala> sqlContext.sql("select A.aid, B.bid from A left join B on A.aid=B.bid where B.bid<2").explain

== Physical Plan ==
Project [aid#15,bid#17]
+- Filter (bid#17 < 2)
   +- BroadcastHashOuterJoin [aid#15], [bid#17], LeftOuter, None
      :- Scan ParquetRelation[aid#15,aVal#16] InputPaths: file:/home/mohit/ruleA
      +- Scan ParquetRelation[bid#17,bVal#18] InputPaths: file:/home/mohit/ruleB

This is a watered-down example from a production issue which has a huge performance impact.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org