3 ms·

> Every time a system responds to a create/update/execute request, drop an equivalent message into an event stream. Don't we call that just "a WAL"?

• klysm 5y ago
  Write ahead log is something with more specific and semantics. You write something in a WAL _ahead_ of some process for durability sake.
  • jhgb 5y ago
    Possibly, but it records the complete information about actions to be performed on some system, which presumably is what the "fat events" were supposed to be about (unless I misinterpreted it somehow).
    • morelisp 5y ago
      To the extent a fat event is a "RESTful" event, it should definitely not be about the actions but about the current state of things. Now, maybe it only emits when that state has changed, but that's distinct from what's in the message. What exactly a WAL contains depends on the specific storage, but it's commands at least as often as it's state - probably more often since you want your WALs to be tiny and they often also facilitate rollback. In general you wouldn't want to emit a fat event until the data is firmly committed to its system of record which is usually not the event system itself; in that use case it will be a kind of 'write behind' log.