“Total Disk I/O Checks” reports the number of times engines checked for disk I/O.
When a task needs to perform I/O, the Adaptive Server engine running that task immediately issues an I/O request and puts the task to sleep, waiting for the I/O to complete. The engine processes other tasks, if any, but also loops to check for completed I/Os. When the engine finds completed I/Os, it moves the task from the sleep queue to the run queue.
