1. A system, comprising: one or more processors configured to: perform a plurality of transactions, including a current transaction and one or more concurrent transactions; wherein: the current transaction has a current start time and a current target commit time, and the one or more concurrent transactions are committed to a data model at corresponding one or more intermediate times after the current start time and before the current target commit time; perform a commit processing check to determine whether the current transaction can be committed consistently with a set of one or more constraints relating to data in the data model, the commit processing check being based at least in part on: a snapshot corresponding to the current transaction that is a snapshot of at least a part of the data model as of the current start time, and one or more changes to the data model made by the one or more concurrent transactions; in the event that it is determined that the current transaction can be committed consistently with the set of one or more constraints relating to the data in the data model, commit the current transaction; and in the event that it is determined that the current transaction cannot be committed consistently with the set of one or more constraints relating to the data in the data model, abort the current transaction; and one or more memories coupled to the one or more processors, configured to provide the one or more processors with instructions.