[CASSANDRA-16316] Tracing continues after session completed

• Type: Bug
• Status: Open
• Priority: Normal
• Resolution: Unresolved
• Fix Version/s: 2.2.x, 3.0.x, 3.11.x
• Component/s: Observability/Tracing
• Bug Category: Degradation - Resource Management
• Severity: Normal
• Complexity: Normal
• Discovered By: User Report
• Platform: All
• Assignee: Jan Karlsson
• Reporter: Jan Karlsson

Authors

Jan Karlsson

• Created: 08/Dec/20 08:47
• Updated: 18/Dec/20 13:01

Description

We saw the system_trace.events table increasing in size continuously without any trace requests being issued.

I traced the issue back to a specific version and patch. I believe we have removed the call to reset the trace flag in CASSANDRA-15041 which causes tracing to continue in the thread even after it is finished with the request.

Reproduced like follows:
1. ccm test -n 1 -v 3.11.9

2. Enable authentication/authorization

3. Set permissions_update_interval_in_ms: 1000 (It works if this value is default value. I am guessing this is because the update is done in the calling thread)

4. select * from some table a bunch of times until PermissionRoleCache is refreshed

5. Watch system_traces.events grow