Represents the context under which a database runtime method is executed.
In particular it provides details about the currently executing txn to runtime operations.
More generally it acts as a container for information that database operations may require to function correctly.
Classifies a transaction according to its workload.
A transaction can be executing a reducer.
It can be used to satisfy a one-off sql query or subscription.
It can also be an internal operation that is not associated with a reducer or sql request.