[psanford]

I wrote a library[0] to let you concurrently update a sqlite db in s3 safely. It uses the little known sqlite sessions extension plus s3 compare-and-swap on a small metadata file to make this work reasonably efficiently and safely. I have been enjoying it for a bunch of small projects where I want a lambda function to have a db for state but I don't want to pay for a full database instance.

[0]: https://github.com/psanford/s3db

[password4321]

This is exactly what I had dreamed of except without being aware of the session extension... I put it off because I thought I would have to create a layer opening sequential partial sqlite dbs and somehow filtering to the most recent version of each record in-between compactions.

It sounds like sqlite sessions handles the hardest part and you've sanded down some of the rough edges while implementing the glue bits for s3 (generously licensed MIT); thanks for the heads-up!