Change websocket cleanup performance from O(n^2) to O(n).#429
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marshallbrekka wants to merge 1 commit intoNetflix:masterfrom
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Change websocket cleanup performance from O(n^2) to O(n).#429marshallbrekka wants to merge 1 commit intoNetflix:masterfrom
marshallbrekka wants to merge 1 commit intoNetflix:masterfrom
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Move subscription tracking to a dict keyed by the underlying websocket object. Changes the cleanup from two nested for loops (the 2nd being the unsubscribe_from method), to a single loop with (the common case) deleting a single key from a dict.
savingoyal
approved these changes
Jun 17, 2024
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lgtm! we can ship this once @saikonen approves |
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@savingoyal @saikonen is there any update here, anything I can do to help get this upstreamed? thanks! |
saikonen
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Aug 23, 2024
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overall changes look good. had one minor note on the filter part.
linter step is failing due to unrelated reasons, this is fixed in master now if you want to rebase
| # This is primarily useful when calling `unsubscribe_from` during the cleanup | ||
| # loop in the event handler. | ||
| for k in list(self._subscriptions.keys()): | ||
| for sub in self._subscriptions[k]: |
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note to self: no KeyError possible due to self._subscriptions being a defaultdict(list)
| self.subscriptions = list( | ||
| filter(lambda s: uuid != s.uuid or ws != s.ws, self.subscriptions)) | ||
| self._subscriptions[ws] = list( | ||
| filter(lambda s: uuid != s.uuid or ws != s.ws, self._subscriptions[ws])) |
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is the ws != s.ws check necessary anymore as the subscription is keyed per websocket?
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Move subscription tracking to a dict keyed by the underlying websocket object.
Changes the cleanup from two nested for loops (the 2nd being the unsubscribe_from method), to a single loop with (the common case) deleting a single key from a dict.
We found that with a sufficient number of disconnected clients, and long gaps between database activity, the cleanup could end up taking multiple hours. This would cause the python web service to become unresponsive.