This attribute defines the number of messages that are cached by the DBQD process when it requests a block of messages from a database message queue.
Each BG and
WISMBD process requests a message from one of its allocated message queues whenever it is not either already processing a message or sleeping. The
DBQD process receives this request and returns a message from its cache for the specified queue. If the cache is empty, the
DBQD process requests another block of
DBQD_MAX_CACHED_MESSAGES messages from the database message queue to refill the cache.
The rate at which messages are processed from the cache depends upon the number of BG and
WISMBD processes that are running, and the type of procedure being processed. For example, procedures involving significant use of deadlines or EAI steps would take longer to process than those involving normal steps.
Increasing the DBQD_MAX_CACHED_MESSAGES value increases the amount of memory used by the
DBQD process and the time required to perform the caching operation. Decreasing this value means that the process needs to access the database to refill its cache more often.