Diagnosing regular periodic high memory usage

Using cloud provider’s standard system monitoring tools, we’re getting alerts about the same time most days because memory utilization was over 80% for 10+ minutes continually. This state continues for maybe 30 to 60 minutes or more (the duration seems to vary by day) starting right around the same time.

  • Anyone seen something like this that might have an idea where to start looking? Or, alternatively …
  • Is there any easy way to look at scheduled jobs within the application stack that might be happening at this pattern and a culprit?

Backups? Especially if you’ve got lots of uploads. You can look at /sidekiq.

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Nope, backups were my first idea too. Backups (both Discourse and cloud provider) are only happening weekly. (Which I should probably change but not until I get this ghost tracked down!) :thinking:

So I took a look at https://discourse.example.org/sidekiq/scheduler and it seems that all the jobs there are on a period rotation and not necessarily at a certain time of day. Does anyone know if that’s right? If so, is that period based on the startup time of the app container?

It’s almost bound to be a big or bunch of big queries. Dashboard re-calc and Top recalc come to mind as two possible hogs.

80% is not all bad though, means you aren’t over-stressing the system (and going into swap), but utilisation is efficient and you are making good use of your (virtual) hardware?

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