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Type:
Investigation
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Resolution: Won't Do
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Priority:
Major - P3
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Affects Version/s: None
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Component/s: None
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None
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Not Needed
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Developer Tools
There will be a new section in serverStatus that tracks mutex contentions for a subset of service-level locks.
Description of Linked Ticket
Summary
Track the number of contended mutex acquisitions and report that to external observers (e.g. through FTDC metrics). Additionally, report individual mutex metrics for special instances marked by MongoDB engineers (e.g. the replication coordinator mutex). Collecting and reporting these metrics should have no performance impact on the happy path, and minimal cost on acquiring a contended mutex.
Motivation
The primary goal is to make an observable mutex type with negligible performance overhead to address the requirements specified in SERVER-90745 and similar tickets. The diagnostics should help TSEs and server engineers identify contended mutex acquisitions in testing and production.