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Java log4j2: Log messages go missing sporadically, especially in multi-threaded scenarios

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#3,488 1 comment 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Needs clarification
Activity status
Stale
Tech stack
azure, java
Domain
observability

Research direction

No source file or test is named. Clone the linked azure-app-insights reproduction and repeatedly run it with parameter 3, using the listed JDK and environments; inspect behavior around generalExportQueueCapacity and missing messages. Done means the sporadic loss is reproducible, explained, and addressed with verification that all messages reach App Insights.

Written by the indexing model from the issue text.

Description

Expected behavior

All log messages should be sent to App Insights

Actual behavior

Log messages go missing sporadically in multi-threaded scenarios when several threads are logging simultaneously
Application Insights log file has no errors

To Reproduce

Clone https://github.com/hexagon-ecosys/azure-app-insights.git and run it several times by supplying the single parameter value '3' (which runs it in multi-threaded mode with long messages upto 20K characters in length)

System information
  • App Insights 3.4.18
  • MacOS 14.2 and Alpine 3.18 with Eclipse Temurin JDK 21
Additional Information
  • I cannot not see any pattern to this issue other than the fact that it happens more during weekdays (we're based in New York City) and less during the weekends
  • I am using the preview option generalExportQueueCapacity. Without it, I can see error messages in the Application Insights log file asking that it be set
Dominant language
Java
Stars
327
Forks
222
Avg merge
22h 34m
Merged PRs (30d)
14

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