Code Structure

Check out https://github.com/microsoft/FASTER. More details will be added in future.

Lifecycle of a Read operation for disk data

Here is the sequence of steps from FASTER side, during a Read operation for disk data:

1. User issues Read operation
2. We create a PendingContext object for the read
3. The HandleOperationStatus() call adds PendingContext object to ioPendingRequests dictionary
4. Create AsyncIOContext which has pointer to a readyResponses queue (also called callbackQueue), for that session
5. Issue IO with AsyncIOContext as param
6. …
7. IO callback accesses readyResponsesqueue, and enqueues the result in there (result is just the AsyncIOContext itself)
8. …
9. User calls CompletePending on session, which does this:
   • Dequeue entry from readyResponses queue
   • Remove item from ioPendingRequests dictionary
   • Finally return result to user via ReadCompletionCallback