[ZOOKEEPER-3793] Request throttling is broken when RequestThrottler is disabled or configured incorrectly.

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 3.6.0
• Fix Version/s: 3.7.0, 3.6.1
• Component/s: server
• Labels: pull-request-available
• Assignee: Michael Han
• Reporter: Michael Han
• Created: 10/Apr/20 17:55
• Updated: 23/Oct/21 18:20
• Resolved: 12/Apr/20 09:16

Description

When RequestThrottler is not enabled or is enabled but configured incorrectly, ZooKeeper server will stop throttling. This is a serious bug as without request throttling, it's fairly easy to overwhelm ZooKeeper which leads to all sorts of issues.

This is a regression introduced in ZOOKEEPER-3243, where the total number of queued requests in request processing pipeline is not taking into consideration when deciding whether to throttle or not, or only taken into consideration conditionally based on RequestThrottler's configurations. We should make sure always taking into account the number of queued requests in request processing pipeline before making throttling decisions.

Issue Links

• links to: GitHub Pull Request #1316