Audit via resource_change ID

[behas]

If a source supports change memory and issues change events for resource changes and inventory creation, and each change event has a unique sequential ID (á la commit hash in Git), then a destination can easily check if it is in sync by comparing it local event id (from its last sync request) with the most recent remote event id.

[zimeon]

If one uses a sequential event ids (different from github that avoids this in favor of something hashlike because sequential ids would require centralized synchronous control) and if the destination knows both that it has never missed and update (every event in sequence since start) and has the most recent update, then this would be a form of audit. It would still be a rather weaker check than actually verifying content so perhaps less broadly applicable.

[behas]

Sequential doesn't necessary mean that the itself needs to be sequential (1,2,3,...). It can also be sth. hashlike as long as the changememory remembers their temporal order. E.g. a git repository knows about the temporal order of commits, but doesn't encode this in the event id. WebDav works the same way; it uses hash-like event IDs and demands the the source knows about their sequence.

This clearly works only if a source has changememory but I think it would be a fast and efficient, but certainly weaker audit check than a full inventory comparision.