[SPARK-22681] Accumulator should only be updated once for each task in result stage

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.2.0
• Fix Version/s: 2.3.0
• Component/s: Spark Core
• Assignee: Carson Wang
• Reporter: Carson Wang
• Created: 04/Dec/17 12:31
• Updated: 05/Dec/17 17:15
• Resolved: 05/Dec/17 17:15

Description

As the doc says "For accumulator updates performed inside actions only, Spark guarantees that each task’s update to the accumulator will only be applied once, i.e. restarted tasks will not update the value."
But currently the code doesn't guarantee this.

Issue Links

• links to: [Github] Pull Request #19877 (carsonwang)