edit: author here

Our current FUSE implementation is specific to DuckDB and does make (as well as validate) some assumptions about DuckDB's access patterns to the underlying files. In this case - we know that currently DuckDB always truncate the WAL on successful checkpoint - which triggers a Differential Storage snapshot under the hood.

We are working on future-proofing this setup by removing our reliance on some of these assumptions and having our FUSE implementation act much more like a generic FS moving forward.

Though in general the truncation of the WAL is still usually a good time to snapshot the database, as the truncation means that the only "state" needed to reconstruct the current database is completely captured in the database file.