Constraint-based consistency with snapshot isolation

摘要

Efficient processing of concurrent atomic transactions is provided by identifying the constraints that need to be satisfied for correct application behavior. With these constraints identified, commit processing for a transaction can then refer to the constraints to see if committing the current transaction causes a problem with the constraints. If there is a conflict with the constraints, the transaction aborts. If there is no conflict with the constraints, the transaction commits.

主权项

1. A method of ensuring consistency of concurrent transactions relating to a data model, the method comprising:
providing a set of constraints relating to data in the data model; performing at least two transactions, wherein each of the at least two transactions has a corresponding start time, and relies on a corresponding snapshot of part or all of the data model as of the start time; wherein a current transaction of the at least two transactions has a current start time and a current target commit time, and wherein one or more concurrent transactions of the at least two transactions have committed to the data model at one or more intermediate times after the current start time and before the current target commit time; performing a commit processing check that automatically determines whether the current transaction can be committed consistently with the set of constraints from at least a) the snapshot of the current transaction and b) changes to the data model made by the one or more concurrent transactions; automatically committing the current transaction if it can be made consistently with the set of constraints; and automatically aborting the current transaction if it cannot be made consistently with the set of constraints.