[5.x] Metrics snapshot config proposal and fix for race condition #936
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glamorous
commented
Nov 26, 2020
glamorous
commented
- New option in the config so you will be able to save snapshots on smaller timestamps then 5 minutes.
- Fix for a race condition when you have slow or fast servers and lock in redis isn't yes released because the lock was now the same length as the time the scheduler is been called. (bug noticed by @Dries-Vandenneucker and reported by myself in Snapshot miss lock time to time #935)
This way you can schedule snapshots every minute, every two minutes and set the locking time the same so they can be stored and shown in the horizon dashboard.
Because the scheduler had the same amount of time, you can have a race condition that lock isn't over yet.
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driesvints
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driesvints
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Nov 27, 2020
| @@ -31,7 +31,7 @@ class SnapshotCommand extends Command | |||
| */ | |||
| public function handle(Lock $lock, MetricsRepository $metrics) | |||
| { | |||
| if ($lock->get('metrics:snapshot', 300)) { | |||
| if ($lock->get('metrics:snapshot', config('horizon.metrics.snapshot_lock', 300) - 30)) { | |||
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The -30 here is a slight change in behavior. We may not want to do that on a minor/patch release.
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That's the bugfix. Can be smaller too, but the point is:
- Cron executes at 09:00:00
- Command for metrics runs at 09:00:05 and is taken
- Metric snapshot is taken
- Cron executes at 09:05:00
- Command for metrics runs at 09:05:01 and is not available, because lock is till 09:05:05.
That's the bug. The -30 is "a" solution, not the only one off-course. I'm open for suggestions.
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