druid/extensions-core
Gian Merlino 8ee324c7e7
MSQ: Cancel workers more quickly. (#16158)
Prior to this patch, when canceled, workers would keep trying to contact
the controller: they would attempt to report an error, and if they were
in the midst of some other call (like a counters push) they would keep
trying it.

This can cause cancellation to be delayed, because the controller shuts
down its HTTP server before it cancels workers. Workers are then stuck
retrying calls to the controller that will never succeed. The retry loops
are broken when the controller gives up on them (one minute later) and
exits for real. Then, the controller failure detection logic on the worker
detects that the controller has failed, and the worker finally shuts down.

This patch speeds up worker cancellation by bypassing communication
with the controller. There is no real need for it. If the controller
canceled the workers, it isn't interested in further communications from
them. If the workers were canceled out-of-band, the controller can
detect this through worker monitoring and report it as a WorkerFailed
error.
2024-03-19 14:21:22 +05:30
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