verneuil VS mvsqlite

It'd be process wide. If you want an example can check out the example using a vfs here. There's an explicit passing of vfs there and an implicit usage of it. https://github.com/backtrace-labs/verneuil/blob/main/examples/rusqlite_integration.rs

It doesn't even have to be WAL-based system. Backtrace Labs has a SQLite virtual file system (VFS) called Verneuil that works similarly but works with the rollback journal instead of the WAL.

https://github.com/backtrace-labs/verneuil/ is one way to address the diffing / read replica part of the problem. I believe it's compatible with gossipping: most of the data is in small content-addressed chunks, with small manifests that tell clients what chunks to fetch and how to reassemble them to recreate a sqlite database. There's already client-side caching to persistent storage, and chunks can be fetched on demand.

Sharing replication data P2P, while retaining the simplicity of a single authoritative writer per database, is explicitly part of the project's long-term goals!

I’ve been using FDB for toy projects for a while. It’s truly rock solid. That being said, I wish there were more layers.

Ideally someone could implement the firestore or dynamodb api on top.

https://github.com/losfair/mvsqlite

For the rough plan, it's Cloud Backed SQLite meets FoundationDB.

- Oh, and if you're wondering about backup to S3, they have that too: https://github.com/libsql/bottomless

- Uh, sqld can integrated with this https://github.com/losfair/mvsqlite, so now your SQLite is backed by FoundationDB!?

- Meanwhile Litestream exists https://github.com/benbjohnson/litestream/

Shameless plug of my [mvSQLite](https://github.com/losfair/mvsqlite) project here! It's basically another distributed SQLite, but with support for everything expected from a proper distributed database: synchronous replication, strictly serializable transactions, + scalable reads and writes w/ multiple concurrent writers.

This project looks really exciting!

I'm working on mvsqlite [1], a distributed SQLite based on FoundationDB. When doing the VFS integration I have always wanted to patch SQLite itself, but didn't because of uncertainty around correctness of the patched version...

A few features on my wishlist:

1. Asynchronous I/O. mvsqlite is currently doing its own prefetch prediction that is not very accurate. I assume higher layers in SQLite have more information that can help with better prediction.

2. Custom page allocator. SQLite internally uses a linked list to manage database pages - this causes contention on any two transactions that both allocate or free pages.

3. Random ROWID, without the `max(int64)` row trick. Sequentially increasing ROWIDs is a primary source of contention, and causes significant INSERT slowdown in my benchmark [2].

[1] https://github.com/losfair/mvsqlite

[2] https://univalence.me/posts/mvsqlite-bench-20220930

That DynamoDB VFS looks cool! I agree that the VFS api makes one think about plenty of crazy ideas. Someone is working on a VFS based on Foundation DB[0] that looks very promising. It was recently discussed here[1]

[0]: https://github.com/losfair/mvsqlite

[1]: https://news.ycombinator.com/item?id=32269287