Release 10.1A: OpenEdge Data Management:
Database Administration

Spin locks

On multi-processor systems, the database engine uses a spin lock algorithm to control access to memory. The spin lock algorithm works as follows: When a process needs a memory resource, it attempts to acquire the resource’s latch. If it cannot acquire the resource’s latch it repeats the attempt. This iterative process is called spinning. If a process fails to acquire a latch after a specified number of spins, the process pauses, or takes a nap, before trying again. If a process repeatedly fails to acquire a latch, the length of its nap is gradually increased. You can set the Spin Lock Retries (-spin) parameter to specify how many times to test a lock before napping.