Details
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New Feature
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Status: Triage Needed
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Normal
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Resolution: Unresolved
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Description
We should be able to view GC pause history in a virtual table.
I think the best approach here is to read from the GC logs. The format was unified in Java 9, and we've dropped older JVM support so I think this is reasonable. The benefits of using logs are that we can preserve it across restarts and we enable GC logs by default.
The downside is people might not have GC logs configured and it seems weird that a feature would just stop working because logs aren't enabled. Maybe that's OK if we call it out, or error if people try to read from it and the logs aren't enabled. I think if someone disables -Xlog:gc then an error might be fine as I don't expect it to happen often. I think I lean towards this from a usability perspective, and Microsoft has a project to parse them, but I haven't used it so I'm not sure if it's suitable for us.
At a minimum, pause time should be it's own field so we can query for pauses over a specific threshold, but there may be other data we want to explicitly split out as well.