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ljharb
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Oct 22, 2018
src/heartbeat.js
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| this.emit('workerStall', workerId); | ||
| this.emit('info:workerHeartbeatDelta', workerId, delta); | ||
| .filter(([, worker]) => !worker.isDead()) | ||
| .filter(([, worker]) => worker.state === 'up').forEach(([workerId]) => { |
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sinc the filters are on their own lines, the forEach should be too
andyfangdz
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Oct 22, 2018
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Changes look good to me. Thanks for doing this!
It looks like we now won’t be detecting stalls that are caused by process startup. This is reasonable as time to first heartbeat should be treated separately. Perhaps a future task 😄
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@andyfangdz yes, though I think we already weren't adequately tracking that due to monitoring only starting after all workers came up for the first time. Monitoring successful boot and start up time is def a useful, but distinct thing. |
When the process backing a worker exits, pool-hall replaces it with a new process. Process start up can take a nontrivial amount of time. The heartbeat module was not aware of process replacement, so it continued expecting heartbeats while the process was starting up. This can lead to a worker being reported as stalled, when it merely booting up, leading to confusion over underlying problem (stalls = infinite loops, process replacement = unhandled errors or the like). This factors in worker state to monitoring and tweaks delta checking to avoid reporting start up time.
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When the process backing a worker exits, pool-hall replaces it with a
new process. Process start up can take a nontrivial amount of time.
The heartbeat module was not aware of process replacement, so it
continued expecting heartbeats while the process was starting up. This
can lead to a worker being reported as stalled, when it merely booting
up, leading to confusion over underlying problem (stalls = infinite
loops, process replacement = unhandled errors or the like).
This factors in worker state to monitoring and tweaks delta checking to
avoid reporting start up time.
/cc @andyfangdz @goatslacker @martinwin