CONCURRENCY CONTROL USING AN EFFECTIVE CHANGE STACK AND TENANT-BASED ISOLATION

Transaction processing is disclosed. A first transaction associated with a first system tenant is received. The first transaction is associated with a transaction effective time. It is determined whether the first transaction modifies data. In the event that the first transaction modifies data, it is determined whether a second transaction is executing that modifies data associated with the first system tenant. In the event that there is not a second transaction executing, the first transaction is executed with respect to the transaction effective time.