> If a transaction executes on a single node, there is no issue. But even
> relaxing this, it boils down to the same principle that governs Firebird
> transactions, which is that any given transaction sees a stable set of
> committed transactions. Records that were committed by a transaction
> that was visibly committed when another transaction starts are visible,
> otherwise a back version (or nothing) is required.

Yup, thanks for the clarification!

Roman