Spotlight on SAP ASE 2.12 - User Guide

Network Checks

Non-Blocking

"Non-Blocking" reports the number of times Adaptive Server performed non-blocking network checks.

With non-blocking network I/O checks, an engine checks the network for I/O and continues processing, whether or not it found I/O waiting.

Blocking

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

Blocking checks occur after an engine yields to the operating system because there are no tasks to process.  The engine 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.

An engine yields to the operating system after it cannot find a runnable task.  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.

* Available only for Adaptive Servers versions prior to 12.5.0.3