From reading the docs, this has an IMO surprising design decision: the “journal” is a stream of bytes, where each append (of a byte string) is atomic and occurs in a global order. The bytes are grouped into fragments, and no write spans a fragment boundary.

This seems sort of okay if writes are self-delimiting and never corrupt, and synchronization can always be recovered at a fragment boundary.

I suppose it’s neat that one can write JSONL and get actual JSONL in the blobs. But this seems quite brittle if multiple writers write to one journal and one malfunctions (aside from possibly failing to write a delimiter, there’s no way to tell who wrote a record, and using only a single writer per journal seems to defeat the purpose). And getting, say, Parquet output doesn’t seem like it will happen in any sensible way.