[KAFKA-6937] In-sync replica delayed during fetch if replica throttle is exceeded

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.11.0.1, 1.0.1, 1.1.0
• Fix Version/s: 1.0.2, 1.1.1, 2.0.0
• Component/s: core
• Assignee: Jun Rao
• Reporter: Jun Rao
• Created: 23/May/18 21:33
• Updated: 25/May/18 23:34
• Resolved: 25/May/18 23:34

Description

When replication throttling is enabled, in-sync replica's traffic should never be throttled. However, in DelayedFetch.tryComplete(), we incorrectly delay the completion of an in-sync replica fetch request if replication throttling is engaged. 

The impact is that the producer may see increased latency if acks = all. The delivery of the message to the consumer may also be delayed.

Issue Links

• links to: GitHub Pull Request #5074