[SPARK-20144] spark.read.parquet no long maintains ordering of the data

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 2.0.2
• Component/s: SQL
• Assignee: Unassigned
• Reporter: Li Jin
• Created: 29/Mar/17 14:20
• Updated: 11/Apr/19 20:27
• Resolved: 04/Apr/17 11:02

Description

Hi, We are trying to upgrade Spark from 1.6.3 to 2.0.2. One issue we found is when we read parquet files in 2.0.2, the ordering of rows in the resulting dataframe is not the same as the ordering of rows in the dataframe that the parquet file was reproduced with.

This is because FileSourceStrategy.scala combines the parquet files into fewer partitions and also reordered them. This breaks our workflows because they assume the ordering of the data.

Is this considered a bug? Also FileSourceStrategy and FileSourceScanExec changed quite a bit from 2.0.2 to 2.1, so not sure if this is an issue with 2.1.

Issue Links

• links to: [Github] Pull Request #22673 (darabos)
• links to: [Github] Pull Request #22673 (darabos)
• links to: GitHub Pull Request #22673