[jchanimal]

The full op-log plus deterministic merging is a great fit for immutable block storage, which can have other security, performance, and cost benefits. I'm building Fireproof[1] to take advantage of recent research in this area. An additional benefit to content addressing the immutable data is that each operation resolves to a cryptographically guaranteed proof (or diff), enforcing causal consistency and allowing stable references to be made to snapshots. This means your interactive, offline-capable, losslessly-merging database can run on the edge or in the browser, but still have the integrity you'd have looked to a centralized database or the blockchain for in the past. (Eg you can drop a snapshot CID into a PDF for signature, or a smart contract, and remove all ambiguity about the referenced state.

[1] https://github.com/fireproof-storage/fireproof

[jitl]

how do such immutable systems deal with redaction eg for GDPR delete requests? Do you need to repack the whole history, and break the existing signature chain?

[jchanimal]

Yes that’s what you’d do. Makes sense to partition eg one chat per database file / proof chain, for lots of reasons including that.