[CASSANDRA-15177] Reloading of auth caches happens on the calling thread

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 4.0-rc1, 4.0
• Component/s: Feature/Authorization
• Bug Category: Degradation - Performance Bug/Regression
• Severity: Normal
• Complexity: Normal
• Discovered By: Unit Test
• Platform: All
• Since Version: 4.0-alpha1

Source Control Link

https://github.com/apache/cassandra/commit/d656f8ac012f4577d22ed7bd3db94c15ae8eb5a9

Test and Documentation Plan

Covered by existing python dtests

• Assignee: Sam Tunnicliffe
• Reporter: Sam Tunnicliffe

Authors

Sam Tunnicliffe

Reviewers

Benjamin Lerer, Brandon Williams

• Created: 20/Jun/19 18:03
• Updated: 25/Apr/21 11:31
• Resolved: 23/Mar/21 10:07

Description

When Guava caches were replaced by their Caffeine equivalents in CASSANDRA-10855, the async reloading of stale AuthCache entries was lost due to the use of MoreExecutors.directExecutor() to provide the delegate executor. Under normal conditions, we can expect these operations to be relatively expensive, and in failure scenarios where replicas for the auth data are DOWN this will greatly increase latency, so they shouldn’t be done on threads servicing requests.

Issue Links

• is caused by: CASSANDRA-10855 Use Caffeine (W-TinyLFU) for on-heap caches