Henry Robinson created SPARK-23973:
--------------------------------------
Summary: Remove consecutive sorts
Key: SPARK-23973
URL: https://issues.apache.org/jira/browse/SPARK-23973
Project: Spark
Issue Type: Improvement
Components: SQL
Affects Versions: 2.4.0
Reporter: Henry Robinson
As a follow-on from SPARK-23375, it would be easy to remove redundant sorts in
the following kind of query:
{code}
Seq((1), (3)).toDF("int").orderBy('int.asc).orderBy('int.desc).explain()
== Physical Plan ==
*(2) Sort [int#35 DESC NULLS LAST], true, 0
+- Exchange rangepartitioning(int#35 DESC NULLS LAST, 200)
+- *(1) Sort [int#35 ASC NULLS FIRST], true, 0
+- Exchange rangepartitioning(int#35 ASC NULLS FIRST, 200)
+- LocalTableScan [int#35]
{code}
There's no need to perform {{(1) Sort}}. Since the sort operator isn't stable,
AFAIK, it should be ok to remove a sort on any column that gets 'overwritten'
by a subsequent one in this way.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org
For additional commands, e-mail: issues-h...@spark.apache.org
