[SPARK-20232] Better combineByKey documentation: clarify memory allocation, better example

• Type: Improvement
• Status: Resolved
• Priority: Trivial
• Resolution: Fixed
• Affects Version/s: 2.1.0
• Fix Version/s: 2.2.0
• Component/s: Documentation

Environment

macOS Sierra 10.12.4
Spark 2.1.0 installed via Homebrew

• Assignee: David Gingrich
• Reporter: David Gingrich
• Created: 05/Apr/17 19:46
• Updated: 13/Apr/17 19:45
• Resolved: 13/Apr/17 19:43

Description

combineByKey docs has a few flaws:

• Doesn't include note about memory allocation (on aggregateBykey)

• Example doesn't show difference between mergeValue and mergeCombiners (both are add)

I have a trivial patch, will attach momentarily.

Issue Links

• links to: [Github] Pull Request #17545 (dgingrich)