A system and method for an ultimate locking mechanism which minimizes a lock period for modifying shared data in a shared database. A process is executed as one or more initial instances and a final instance. Each initial instance reads the shared data from the shared database without acquiring a lock on the shared database. The locking mechanism obtains results that are directed to modifying the shared data and buffers the results at least partially. During or after each of the initial instances, it determines whether the next instance is to be the final one (e.g., the estimated runtime of the next instance is acceptable as the lock period). In response to a positive determination, the final instance of the process is executed. The final instance uses at least one of the buffered results during execution and acquires the lock on the shared database to modify the shared data.