[SPARK-31055] Update config docs for shuffle local host reads to have dep on external shuffle service

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0
• Fix Version/s: 3.0.0
• Component/s: Documentation
• Assignee: Thomas Graves
• Reporter: Thomas Graves
• Created: 05/Mar/20 15:41
• Updated: 09/Mar/20 19:18
• Resolved: 09/Mar/20 19:18

Description

with SPARK-27651 we now support host local reads for shuffle, but only when external shuffle service is enabled. Update the config docs to state that.

Issue Links

• relates to: SPARK-27651 Avoid the network when block manager fetches shuffle blocks from the same host
• links to: GitHub Pull Request #27812