[DOCS-13424] Investigate changes in SERVER-43945: Expose out of order latch acquisitions in serverStatus Created: 18/Feb/20  Updated: 13/Nov/23  Due: 22/May/20  Resolved: 02/Jun/20

Status: Closed
Project: Documentation
Component/s: manual
Affects Version/s: None
Fix Version/s: 4.3.3, Server_Docs_20231030, Server_Docs_20231106, Server_Docs_20231105, Server_Docs_20231113

Type: Task Priority: Major - P3
Reporter: Backlog - Core Eng Program Management Team Assignee: Kay Kim (Inactive)
Resolution: Fixed Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Documented
documents SERVER-43945 Expose out of order latch acquisition... Closed
Duplicate
Participants:
Days since reply: 3 years, 36 weeks, 1 day ago
Epic Link: DOCS: 4.4 Server Release Work

 Description   

Description

Downstream Change Summary

This commit introduced an off-by-default section to serverStatus "latchAnalysis". This section tracks internal resource acquisition history with simple counters. See comments and https://github.com/mongodb/mongo/commit/86efdd6b047927d3a37577a6033bacc709c7ae89#diff-d22a4335737abd53429d1093cd829697R264-R298 for the data schema.

Description of Linked Ticket

Ideally, we would like to serialize Hierarchical Acquisition violations in a way that allows us to investigate and reproduce the violation. To that end, we want to know the Latch name and the ordering of violations. I propose the following opt-in section in serverStatus:

{    ...,
    "latchAnalysis": {
        "hierarchicalAcquitionViolations": {
            "<latchNameHere>": {
                "onAcquire": 2,
                "onRelease": 1
            }
        }
    }
}

The top level "latchAnalysis" allows us to expand this segment with future statistics. The separation of "onAcquire" and "onRelease" into separate monotonically increasing counters will allow us to consider them as a pair to determine the period in which a potential deadlock happened as well as the total violations. This scheme deliberately leaves out the client name.

Scope of changes

Impact to Other Docs

MVP (Work and Date)

Resources (Scope or Design Docs, Invision, etc.)



 Comments   
Comment by Githook User [ 02/Jun/20 ]

Author:

{'name': 'Kay Kim', 'email': 'kay.kim@10gen.com', 'username': 'kay-kim'}

Message: DOCS-13424: 4.4 serverstatus latchAnalysis
Branch: master
https://github.com/mongodb/docs/commit/c8b1b41e64db6b0c5c31cf4b8121d3895a15fada

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