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0 pointsporker9y ago0 comments

> if your event streams contain mostly CRUD (possibly ANY) then you're most likely applying it incorrectly. Its not just a version history of your data.

Thanks for that. I'd made that mistake: I have a system which now needs to become distributed (a copy of it goes offline for a couple of weeks, and has to merge back into the main datastore) and keep a history of changes. It's currently CRUD backed by MySQL, and I'd latched onto event sourcing as what I'd need.

> The event type itself is data, which provides context and semantics over and above the notion of writes and deletes.

OK, going to have to get my head around that :)

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karmajunkie9y ago

See the presentation by Greg Young I linked to in another comment. One thing he talks about towards the end is the application for occasionally connected clients, which is one I'm looking to tackle myself in the next several months. ES may very well serve your needs, but I'd take a step back from the CRUD model and really think about the domain model. Something I do a lot of times when I'm looking at moving away from CRUD in an app is creating a bunch of domain-based command classes, which take over the persistence job, and move the app layer towards talking only to those commands. Still CRUD under the covers, but now there's an abstraction layer above it, and as you get a better delineation of boundaries you start to see where the services will fall out of it and what areas might benefit from ES the most.

[1]https://www.youtube.com/watch?v=LDW0QWie21s

Terr_9y ago

There's nothing wrong with having a system that uses immutable events to represent data, IMO it's mainly a terminology issue: "Event Sourcing" often implies you're recording rather abstract, high-level events that try to capture something about a particular domain. As opposed to, say, a straight diff between two data-dumps.

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