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The linked projects (https://vlcn.io https://vlcn.io and https://github.com/vlcn-io/cr-sqlite https://github.com/vlcn-io/cr-sqlite) are both extremely impressiv

The linked projects (https://vlcn.io https://vlcn.io and https://github.com/vlcn-io/cr-sqlite https://github.com/vlcn-io/cr-sqlite) are both extremely impressive, and open up the possibility of adding "multiplayer" to apps that rely on SQLite for local storage—including web apps, via a WASM build of SQLite.

hummus_bae 4y ago
Could you elaborate? What problem would using CRDTs solve in the context of a web-based app, especially one built with WASM? I've heard of offline-first web apps but am not aware of much use cases for CRDTs there.
- AlexErrant 4y ago
  I'm using cr-sqlite right now in my Anki clone: https://github.com/AlexErrant/Pentive https://github.com/AlexErrant/Pentive It's basically an offline-first flashcard webapp. CR-Sqlite allows for incremental syncing. With Anki (the app from which I'm taking my inspiration), syncing is _not_ incremental - basically it just copies SQLite files around. So for example, the app could be on an iPhone with cards a card `A` reviewed, but the app on an iPad could make changes to the template on which card `A` is based, and that's enough to cause a conflict - you must take changes from only the iPad or only the iPhone. (To be clear - Anki does have some incremental syncing capabilities - I'm picking an intentionally pathological example.) CR-SQLite will mean that everything is incremental, however. Basically makes 3 way merges a breeze (or n-way merges, really).
brunoqc 4y ago
That could be nice with D1.
- 5Qn8mNbc2FNCiVV 4y ago
  D1 is eventually consistent so better not use it with that. I'd rather use Durable Objects
  - AlexErrant 4y ago
    I believe that the entire point of using CRDTs in your database is eventual consistency. (At least, to some degree. The definition/requirements of "consistent" may change from app to app.)
- tantaman 4y ago
  Yep! That was one plan for deploying cr-sqlite to "the cloud." D1, unfortunately, doesn't support loading extensions into SQLite. fly.io, and their sqlite solution, does however! I've been using fly.io to run cr-sqlite in the cloud and act as a sync server for non peer to peer use cases. Eventually I'll have finished up a re-write of strut.io[1] atop vlcn/cr-sqlite which'll serve as a good end to end example of how to make applications with this sort of architecture. Some discussion about this setup on the fly.io forums: https://community.fly.io/t/litefs-many-tens-to-hundreds-of-thousands-of-sqlite-dbs/9977/1 https://community.fly.io/t/litefs-many-tens-to-hundreds-of-t... [1] https://github.com/tantaman/strut https://github.com/tantaman/strut

hummus_bae 4y ago

Could you elaborate? What problem would using CRDTs solve in the context of a web-based app, especially one built with WASM? I've heard of offline-first web apps but am not aware of much use cases for CRDTs there.

AlexErrant 4y ago
I'm using cr-sqlite right now in my Anki clone: https://github.com/AlexErrant/Pentive https://github.com/AlexErrant/Pentive It's basically an offline-first flashcard webapp. CR-Sqlite allows for incremental syncing. With Anki (the app from which I'm taking my inspiration), syncing is _not_ incremental - basically it just copies SQLite files around. So for example, the app could be on an iPhone with cards a card `A` reviewed, but the app on an iPad could make changes to the template on which card `A` is based, and that's enough to cause a conflict - you must take changes from only the iPad or only the iPhone. (To be clear - Anki does have some incremental syncing capabilities - I'm picking an intentionally pathological example.) CR-SQLite will mean that everything is incremental, however. Basically makes 3 way merges a breeze (or n-way merges, really).

brunoqc 4y ago

That could be nice with D1.

5Qn8mNbc2FNCiVV 4y ago
D1 is eventually consistent so better not use it with that. I'd rather use Durable Objects
- AlexErrant 4y ago
  I believe that the entire point of using CRDTs in your database is eventual consistency. (At least, to some degree. The definition/requirements of "consistent" may change from app to app.)
tantaman 4y ago
Yep! That was one plan for deploying cr-sqlite to "the cloud." D1, unfortunately, doesn't support loading extensions into SQLite. fly.io, and their sqlite solution, does however! I've been using fly.io to run cr-sqlite in the cloud and act as a sync server for non peer to peer use cases. Eventually I'll have finished up a re-write of strut.io[1] atop vlcn/cr-sqlite which'll serve as a good end to end example of how to make applications with this sort of architecture. Some discussion about this setup on the fly.io forums: https://community.fly.io/t/litefs-many-tens-to-hundreds-of-thousands-of-sqlite-dbs/9977/1 https://community.fly.io/t/litefs-many-tens-to-hundreds-of-t... [1] https://github.com/tantaman/strut https://github.com/tantaman/strut