[CASSANDRA-16707] JmxHistogram#getRecentValues() is not thread-safe

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0.1, 4.1-alpha1, 4.1
• Component/s: Observability/JMX
• Bug Category: Correctness - Transient Incorrect Response
• Severity: Low
• Complexity: Low Hanging Fruit
• Discovered By: Code Inspection
• Platform: All
• Since Version: 4.0-rc2

Source Control Link

https://github.com/apache/cassandra/commit/e6946e7ddb76bd72109995664289e988b0e9818c

Test and Documentation Plan

n/a

• Assignee: Caleb Rackliffe
• Reporter: Caleb Rackliffe

Authors

Caleb Rackliffe

Reviewers

Brandon Williams, Yifan Cai

• Created: 02/Jun/21 18:24
• Updated: 27/May/22 19:25
• Resolved: 03/Jun/21 18:41

Description

Published JmxHistogram instances do not protect their “last” field. This isn’t a hot path, and there is a multi-part calculation based on it in getRecentValues(), so we should probably just synchronize that method.

Issue Links

• is related to: CASSANDRA-13642 Expose recent histograms in JmxHistograms