Model
Synchronous commit latency
Each step up the ladder adds about one network round trip and one more flush on another machine.
- Flush
- time to make a record durable locally
- Round trip
- round trip to the replica
Worked examples, recomputed
Every number the mechanisms quote for this relationship is recomputed from it, so none of them disagrees with it.
Where it appears
Each mechanism states it in its own names. The general symbol each name stands for is shown with it.
- Persistence & Durability
When a system says "yes, your data is safe", what exactly has it promised, and what did it have to do to keep that promise?