I don't see any implementation of WriteAheadLog interface. Is it used by anyone? Sample code will be very helpful.
I agree. I'd love to see an example of how this is expected to be used. It doesn't seem like all the hooks are there or I don't understand how the hooks are supposed to work.
Astyanax should have given atleast one implmenentation of WriteAheadLog interface. So that users can directly use the available WAL feature.
WAL was a mechanism that was used to provide more robust persistence in the face of temp failures, where all mutations that haven't been successfully persisted are added to the WAL, with the expectation that they could be removed at a later point if and when the mutation succeeded.
The other expectation is to be able to replay a batch of mutations from the WAL when the app resumes at a later point in time.
Overall the feature is not used widely and now we also have atomic batches that do pretty much the same thing.
Please use those instead. This way you don't have to provide a WAL impl.
Closing this out.