Resources
Articles, announcements, interviews, and stories around Event Sourcing and the products built for it.
Ten weeks ago we put ESDM under the MIT license and asked you to tell us what works and what doesn't. ESDM 0.15.0, released last week, is what came back. It is a big release, and most of it traces to someone using ESDM on a real model and reporting what happened: a vocabulary that speaks more than one language, a command that turns a model into a browsable set of pages, a stable way to point at any element from outside the model, and a linter that explains every finding it makes.
There Is No Row to LockOptimistic locking is one of those techniques you learn once and then use everywhere. A version column, an UPDATE ... WHERE version = 7, and whoever arrives second finds zero rows affected and has to try again. It is cheap, it needs no coordination, and it has kept relational systems correct for decades.
Not an Event YetEvery event stored in EventSourcingDB is a CloudEvent. What your application sends in order to write one is not. It is missing seven of the eleven fields a stored event carries, and if you try to supply them yourself, the database rejects the whole request.
Start With One TableYou have been circling Event Sourcing for a while now: long enough to be convinced by the idea, not long enough to have built anything with it. Today you finally stopped reading and picked one table to start with, the one holding who pays you for which plan. Which is when a colleague asks you why. The table works. The reports run. Nobody has complained. And when you are done, it holds the same values it held that morning, so from the outside, you spent an afternoon achieving nothing.
PostgreSQL Is Not an Event StoreThe table takes about fifteen minutes to write. An ID, a stream name, a version number, an event type, a JSON payload, a timestamp. Add a unique constraint, add an index, and you have somewhere to put your events. It is the first thing almost every team reaches for, and for good reason: the database is already running, already backed up, already monitored, and everybody on the team can read it.
Your Progress Bar Doesn't Belong in the Event StoreThe progress bar works. It fills up, users can see how far along their contract review is, and nobody has complained. Then you open the event store and find 312 events for a single contract, 310 of which nobody would have written if that bar did not have to move.