Performance Implications and Special Considerations

Event sourcing gives you a complete history. That history has real costs. This lesson lists the costs honestly and shows the standard way to control each one. None of them is a reason to avoid the pattern. All of them are reasons to plan before you adopt it.

Replay Cost

To load an aggregate, you replay its events in order. Replay time therefore grows with the length of the history. An aggregate with ten events loads fast. An aggregate with 100,000 events does not.

**The cost of a load is set by the length of one aggregate's history, not the size of your system