[SPARK-20773] ParquetWriteSupport.writeFields is quadratic in number of fields

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.1.1
• Fix Version/s: 2.1.2, 2.2.0
• Component/s: SQL
• Labels: easyfix performance
• Assignee: Tim Poterba
• Reporter: Tim Poterba
• Created: 16/May/17 19:24
• Updated: 19/May/17 12:19
• Resolved: 19/May/17 12:18

Description

The writeFields method in ParquetWriteSupport uses Seq.apply to select all elements. Since the fieldWriters object is a List, this is a quadratic operation.

See line 123: https://github.com/apache/spark/blob/ac1ab6b9db188ac54c745558d57dd0a031d0b162/sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/parquet/ParquetWriteSupport.scala

Issue Links

• links to: [Github] Pull Request #18005 (tpoterba)