Fix bitcask_pulse model to know when a keydir may have been frozen. #181
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* Rename `bitcask_nifs:keydir_remove/3` -> * `bitcask_nifs:keydir_remove_int/3`
* Use a compile-time -ifdef magic to add `pulse_log_call()` wrappers
around all keydir NIF calls that can mutate the keydir.
* Make several changes to the bitcask_pulse model:
* Filter out bad reads from either kind of bad folds
* If a bad read happens, that's bad
* If a bad fold happens, then figure out during what period of
at-last-one-folder-is-running-time that the bad result appeared.
Then figure out if a keydir mutating NIF was called; if yes,
then it's possible that the keydir was frozen ... we don't know
for sure, but we won't cause the model to fail in this case.
1. Use `keydir_call` and `keydir_return` for the trace labels for NIF mutations. 2. Only consider *successful* mutations when checking for keydir frozenness.
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@engelsanchez Whatchathink about this model change? |
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Honestly @slfritchie, I'd like to do this in a different way. I think it should be possible to change our internal API to expose the epochs generated inside of Bitcask that determine the visibility of the values for the folds, as well as the epochs used when folding to verify. That way we can determine exactly what we should be seeing and have a stricter model. I will try to give that a go in the 2.0.2 cycle. |
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Fixes #180.
bitcask_nifs:keydir_remove/3-> *bitcask_nifs:keydir_remove_int/3pulse_log_call()wrappersaround all keydir NIF calls that can mutate the keydir.
at-last-one-folder-is-running-time that the bad result appeared.
Then figure out if a keydir mutating NIF was called; if yes,
then it's possible that the keydir was frozen ... we don't know
for sure, but we won't cause the model to fail in this case.