CODEWITHSUNDEEP
cqrsevent-sourcing
Mohsen
Mohsen

Reputation: 4266

Can I use Time as globally unique event version?

I found time as the best value as event version.

I can merge perfectly independent events of different event sources on different servers whenever needed without being worry about read side event order synchronization. I know which event (from server 1) had happened before the other (from server 2) without the need for global sequential event id generator which makes all read sides to depend on it.

As long as the time is a globally ever sequential event version , different teams in companies can act as distributed event sources or event readers And everyone can always relay on the contract.

The world's simplest notification from a write side to subscribed read sides followed by a query pulling the recent changes from the underlying write side can simplify everything.

Are there any side effects I'm not aware of ?

Upvotes: 0

Views: 111

Answers (1)

Alexey Zimarev
Alexey Zimarev

Reputation: 19630

Time is indeed increasing and you get a deterministic number, however event versioning is not only serves the purpose of preventing conflicts. We always say that when we commit a new event to the event store, we send the new event version there as well and it must match the expected version on the event store side, which must be the previous version plus exactly one. If there will be a thousand or three millions of ticks between two events - I do not really care, this does not give me the information I need. And if I have missed one event on the go is critical to know. So I would not use anything else than incremental counter, with events versioned per aggregate/stream.

Upvotes: 2

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