Ensure reconnecting workers do not loose required data #5436
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fjetter
commented
Oct 18, 2021
| @@ -4339,9 +4343,9 @@ async def add_worker( | |||
| worker_msgs[address] = [] | |||
| worker_msgs[address].append( | |||
| { | |||
| "op": "free-keys", | |||
| "op": "remove-replicas", | |||
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This is the relevant change
crusaderky
approved these changes
Oct 18, 2021
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Again a deadlock masked by mark.repeat flags. We should be more careful with these flags. This time, at least, this showed up as AssertionErrors in tests
If a worker briefly disconnects it has the chance to register what tasks it already has in memory and is currently executing. If it has data which is already released, it is also asked to release this. However, this introduces a subtle race condition where the worker is asked to release all it's data although we simultaneously would expect him to compute that keys dependent. Therefore, we should use the safe handler (remove-replica) instead of the strict handler (free-keys). See comment below for the proper section.
I took this chance to clean up the signature around free-keys to be in alignment with the rest
test_worker_reconnects_mid_compute_multiple_states_on_schedulerflaky #5377