SQLite async connection pool for high-performance

This is strange on so many levels.

SQLite does not even do network I/O.

How does sharing a connection (and transaction scope) in an asyncio environment even work? Won’t you still need a connection per asyncio context?

Does sqlite_open really take long compared to the inevitable contention for the write lock you’ll see when you have many concurrent contexts?

Does sqlite_open even register in comparison with the overhead of the python interpreter?

What is an asyncio SQLite connection anyways? Isn’t it just a regular one that gets hucked into a separate thread?

If you're talking to a 100KB SQLite database file this kind of thing is likely unnecessary, just opening and closing a connection for each query is probably fine.

If you're querying a multi-GB SQLite database there are things like per-connection caches that may benefit from a connection pool.

> What is an asyncio SQLite connection anyways? Isn’t it just a regular one that gets hucked into a separate thread?

Basically yes - aiosqlite works by opening each connection in a dedicated thread and then sending async queries to it and waiting for a response that gets sent to a Future.

https://github.com/omnilib/aiosqlite/blob/895fd9183b43cecce8...

> If you're querying a multi-GB SQLite database

In which case SQLite is probably the wrong tool for the job, and you should be using Postgres or MySQL that is actually designed from the ground up for lots of concurrent connections.

SQLite is amazing. I love SQLite. But I love it for single-user single-machine scenarios. Not multi-user. Not over a network.

Multi-GB is tiny these days.

I didn't say anything about concurrent access. SQLite with WAL mode is fine for that these days for dozens of concurrent readers/writers (OK only one writer gets to write at a time, but if your writes queue for 1-2ms who cares?) - if you're dealing with hundreds or thousands over a network then yeah, use a server-based database engine.

I always had troubles having multiple processes get write access to the sqlite file. For example if I have node.js backend work with that file, and I try to access the file with different tool (adminer for example) it fails (file in use or something like that). Should it work? I don't know if I'm doing something wrong, but this is my experience with multiple projects.