Suppressing Certain Events for a Connector

On systems with OW38840 installed or which are at OS/390® Release 9 or higher, connectors to a cache structure may request that the system suppress certain connection and disconnection events that the connector might otherwise generate. Suppressing these events (New Connection, Existing Connection, Rebuild New Connection, Rebuild Existing Connection, and Disconnected or Failed Connection) may provide a significant performance benefit at connect time to connectors who do not need the information presented in these events.

Note that suppression of these events is on a per-connection basis, where it is the ORIGINATION of the event that is suppressed, not the RECEIPT of the event. A review of the events and how they originate follows:

A New Connection event notifies existing connectors of a new connection to the structure. The event originates from the new connector.
An Existing Connection event notifies a new connector to the structure of all the current existing connections to the structure. The event originates from the new connector.
A Rebuild New Connection event notifies existing connectors of a new connection to the new structure. The event originates from the new connector.
A Rebuild Existing Connection event notifies a new connector of all the current existing connectors to the new structure. The event originates from the new connector.
A Disconnected or Failed Connection event notifies all active connectors to the structure that a connector has either disconnected or failed. The event originates from the connector that either disconnected or failed.

To understand the effect of using SUPPRESSEVENTS, consider the following:

A connection that is suppressing the origination of events may nevertheless receive such events for another connection to the structure that is NOT suppressing the origination of events. In the case of response-required events, this connection is still required to provide responses to any such event that is presented to it, regardless of whether the connection is suppressing events itself.
When a connection is suppressing the origination of events, other connections will not receive the suppressed events originating from that connection, even if the other connections themselves are NOT suppressing events.

Also note that depending on whether OW38840 is present on the system where the connection is running (or whether the system is at OS/390 Release 9 or higher), a request to suppress events may or may not be honored for the current connection.