Saving shared memory in sharing a buffer area

An area called a message-storing buffer pool saves service requests on the shared memory and is secured for each user server. When this area is shared among multiple user servers, the shared memory used by a user server schedule can be saved. If the message-storing buffer tool is shared, specify the following definitions in the concerned nodes.

Specify a user server group name (schedule buffer group name) that shares a buffer area in the scdbufgrp operand in the schedule service definition.
Specify a schedule buffer group name using the scdbufgrp operand in the user service definitions for every user server to be shared.

If there is no schedule buffer group name specified in the user service definitions, an error will occur when starting the user server.

Figure 3-53 illustrates the shared buffer area.

Figure 3-53 Sharing a buffer area

[Figure]

Organization of this subsection: (1) User servers that specify sharing buffer areas; (2) Notes for sharing a buffer area

(1) User servers that specify sharing buffer areas

Specifying the sharing of a buffer area is only valid for a server that receives requests from the queue. Even if the sharing of a buffer area is specified for a server that receives requests from the socket, the specification will be ignored and be executed without sharing the buffer area.

(2) Notes for sharing a buffer area

When the processes of the user servers that have sharing specified are started simultaneously, a conflict occurs in the buffer area and schedule performance may decrease. Share the buffer area only if the user servers use non-resident processes, or when it is obvious that the user servers share the buffer simultaneously.

3.4.4 Saving shared memory in sharing a buffer area

(1) User servers that specify sharing buffer areas

(2) Notes for sharing a buffer area