sqlite_scanner VS dqlite

It's not a dumb question at all. I'm pretty knowledgeable with DBs and still find it very difficult to understand how many of these front-end/pass-through engines work.

Checkout Postgres Foreign Data Wrappers. That might be the most well known approach for accessing one database through another. The Supabase team wrote an interesting piece about this recently.

https://supabase.com/blog/postgres-foreign-data-wrappers-rus...

You might also want to try out duckdb's approach to reading other DBs (or DB files). They talk about how they can "import" a sqlite DB in the above 0.7.0 announcement, but also have some other examples in their duckdblabs github project. Check out their "...-scanner" repos:

https://github.com/duckdblabs/postgres_scanner

https://github.com/duckdblabs/sqlite_scanner

DuckDB can actually read SQLite or Postgres directly! In the SQLite case, something like Litestream plus DuckDB could work really well!

Also, with Pyarrow's help, DuckDB can already do this with Delta tables!

https://github.com/duckdblabs/sqlite_scanner

https://github.com/duckdblabs/postgresscanner

Excellent question! I'll jump in - I am a part of the DuckDB team though, so if other users have thoughts it would be great to get other perspectives as well.

First things first - we really like quite a lot about the SQLite approach. DuckDB is similarly easy to install and is built without dependencies, just like SQLite. It also runs in the same process as your application just like SQLite does. SQLite is excellent as a transactional database - lots of very specific inserts, updates, and deletes (called OLTP workloads). DuckDB can also read directly out of SQLite files as well, so you can mix and match them! (https://github.com/duckdblabs/sqlitescanner)

DuckDB is much faster than SQLite when doing analytical queries (OLAP) like when calculating summaries or trends over time, or joining large tables together. It can use all of your CPU cores for sometimes ~100x speedup over SQLite.

DuckDB also has some enhancements with respect to data transfer in and out of it. It can natively read Pandas, R, and Julia dataframes, and can read parquet files directly also (meaning without inserting first!).

Does that help? Happy to add more details!

If you're interested in this, here are some related projects that all take slightly different approaches:

- LiteSync directly competes with Marmot and supports DDL sync, but is closed source commercial (similar to SQLite EE): https://litesync.io

- dqlite is Canonical's distributed SQLite that depends on c-raft and kernel-level async I/O: https://dqlite.io

- cr-sqlite is a Rust-based loadable extension that adds CRDT changeset generation and reconciliation to SQLite: https://github.com/vlcn-io/cr-sqlite

Slightly related but not really (no multi writer, no C-level SQLite API or other restrictions):

- comdb2 (Bloombergs multi-homed RDMS using SQLite as the frontend)

- rqlite: RDMS with HTTP API and SQLite as the storage engine, used for replication and strong consistency (does not scale writes)

- litestream/LiteFS: disaster recovery replication

- liteserver: active read-only replication (predecessor of LiteSync)

I'd be curious for a similar tuning with Dqlite: https://github.com/canonical/dqlite

Anyone knows how the DB this is about, https://rqlite.io/, compares with https://dqlite.io/ by Canonical (both seem to be distributed versions of sqlite)?

For folks' context, the new tool that's being discussed in the thread mentioned by the parent here is litefs [0], as well as which you can also look at rqlite [1] and dqlite [2], which all provide different trade-offs (e.g. rqlite is 'more strongly consistent' than litefs).

[0]: https://github.com/superfly/litefs

[1]: https://github.com/rqlite/rqlite

[2]: https://github.com/canonical/dqlite

I presume you're familiar with https://github.com/canonical/dqlite (made by my employer) and https://github.com/rqlite/rqlite (unrelated)? How will mvsqlite compare to those?

Check out dqlite, it's sqlite but with a raft consensus to distribute changes through a log: https://dqlite.io/ You can link it in as a library too, it sounds like exactly what you want.