Blocking

“Blocking” reports the number of times Adaptive Server performed blocking network checks.

After an engine completes a task, it loops waiting for the network to deliver a runnable task. After a certain number of loops (determined by the sp_configure parameter runnable process search count), the Adaptive Server engine goes to sleep after a blocking network I/O.

When an engine yields to the operating system because there are no tasks to process, it wakes up once per clock tick to check for incoming network I/O. If there is I/O, the operating system blocks the engine from active processing until the I/O completes.

If an engine has yielded to the operating system and is doing blocking checks, it might continue to sleep for a period of time after a network packet arrives. This period of time is referred to as the latency period. You can reduce the latency period by increasing the runnable process search count parameter so that the Adaptive Server engine loops for longer periods of time.

See the System Administration Guide for more information.