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Comment by katsura | Hacker News Reader

MongoDB imitators? Wasn't CouchDB before MongoDB? CouchDB also stores JSON documents. They did create an imitation of the Mongo query syntax, but the document model doesn't seem to originate from Mongo, as far as I can tell.

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In some ways it is another reflection of the unix philosophy "worse is better". The CouchDB wire protocol is really complex because A) it starts with an almost full HTTP stack and is "REST-like", and B) prioritized multi-database synchronization and replication first and up front, which is incredibly powerful and useful, but makes compatible implementations a lot harder to write. MongoDB's wire protocol is simple, stupid, relatively efficient (binary encoding of JSON over plaintext JSON encodings), had a query language that specifically wasn't built on REST terms, and was so simple to implement that every database could do it (and have done it).

MongoDB's protocol has fewer features (RIP easy synchronization and replication) but worse is better and if the "core" feature of a database it its query language, then the best/worst query language won, the simple, dumb, easy to replicate one.

To be fair, I'd love a plugin/framework/microservice you could simply on top of Postgres for having CouchDB's offline synchronization capabilites. Like the syncing capabilites for mobile and other "sometimes offline" devices are fire. But in my stack, everything else is already running in a Postgres already, and that's the source of truth.

At one point I started to explore what you would need to adapt any MongoDB compatible DB to work with CouchDB-style synchronization. The biggest problem is you need a consistent Changes view of the database and that's optional from MongoDB-provider to MongoDB-provider. Had I continued on that project it probably would have wound up Azure CosmosDB-specific, specific enough that it didn't feel particularly good for ROI, and was starting to feel like a "back to the drawing board/time to leave CouchDB" situation. It's interesting to wonder if the CosmosDB/DocumentDB pieces that Microsoft is open sourcing (as mentioned in the article here) would eventually include a Postgres extension for their Changes view? Had that been done when I was evaluating options in that past project, it might have lent more weight to that ROI decision that it would also support open source Postgres databases with these open source Document DB extensions.

We are working on this: https://www.powersync.com/

We started with Postgres and added support for MongoDB after they deprecated Atlas Device Sync in September last year.

You mean like https://zero.rocicorp.dev/ or https://electric-sql.com/ ?

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