materialize: don't use locks in the extended logger #2043
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williamhbaker
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mdibaiee
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Oct 11, 2024
materialize-boilerplate/logging.go
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| asyncLog() | ||
| l.mu.Unlock() | ||
| }, loggingFrequency) | ||
| return repeatAsync(func() { asyncLog() }, loggingFrequency) |
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Can be simplified to:
repeatAsync(asyncLog, loggingFrequency)
The use of a mutex in both the extended logger event handler and the async logger functions was simple, but there was a potential deadlock if the event handler needed to stop the logger and wait for it to stop while holding the lock, and the logger timer ticked over at nearly the same instant making the logger need to get the lock also to finish its last log before exiting. This updates the extended logger to not use locks at all, since it wasn't far from being able to do that in the first place. The "count" values that are read concurrently by the async loggers have been changed to use atomics, and for good measure the "round" counter is provided as an explicit argument to them, even though it doesn't strictly need to be, it's just easier to understand this way.
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Description:
The use of a mutex in both the extended logger event handler and the async logger functions was simple, but there was a potential deadlock if the event handler needed to stop the logger and wait for it to stop while holding the lock, and the logger timer ticked over at nearly the same instant making the logger need to get the lock also to finish its last log before exiting.
This updates the extended logger to not use locks at all, since it wasn't far from being able to do that in the first place. The "count" values that are read concurrently by the async loggers have been changed to use atomics, and for good measure the "round" counter is provided as an explicit argument to them, even though it doesn't strictly need to be, it's just easier to understand this way.
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(How does one use this feature, and how has it changed)
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