[SPARK-14628] Remove all the Options in TaskMetrics

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0.0
• Component/s: Spark Core
• Target Version/s: 2.0.0
• Assignee: Wenchen Fan
• Reporter: Reynold Xin
• Created: 14/Apr/16 08:00
• Updated: 18/Apr/16 03:06
• Resolved: 15/Apr/16 22:39

Description

Part of the reason why TaskMetrics and its callers are complicated are due to the optional metrics we collect, including input, output, shuffle read, and shuffle write. Given their values are zero, I think we can always track them. It is usually very obvious whether a task is supposed to read any data or not. By always tracking them, we can remove a lot of map, foreach, flatMap, getOrElse(0L) calls throughout Spark.

Issue Links

• links to: [Github] Pull Request #12388 (rxin)
• links to: [Github] Pull Request #12417 (cloud-fan)
• links to: [Github] Pull Request #12462 (cloud-fan)