[SPARK-16419] EnsureRequirements adds extra Sort to already sorted cached table

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Duplicate
• Affects Version/s: 1.6.2
• Component/s: SQL
• Assignee: Unassigned
• Reporter: Mitesh
• Created: 07/Jul/16 15:33
• Updated: 30/Aug/16 20:23
• Resolved: 30/Aug/16 20:23

Description

EnsureRequirements compares the required and given sort ordering, but uses Scala equals instead of a semantic equals, so column capitalization isn't considered, and also fails for a cached table. This results in a SortMergeJoin of a cached already-sorted table to add an extra sort.

Issue Links

• duplicates: SPARK-17271 Planner adds un-necessary Sort even if child ordering is semantically same as required ordering
• links to: [Github] Pull Request #14092 (MasterDDT)