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-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org