Abstract: Provided are a method, computer program product and system for providing indexed queue support for efficient retrieval of messages from a queue. An index key for expediting message retrieval is assigned to a message when the operation of placing the message on a queue is committed. The index key assigned at commit time comprises an attribute (such as a message ID or correlation ID) specified by the sending application program, which placed the message on the queue. This deferred assignment of an index key until commit time means that the index key can be used to search for messages having the particular attribute without any possibility of identifying messages for retrieval before the messages have been committed. This maintains transactional requirements of a transaction-oriented messaging system which requires a message to only be made available for retrieval by receiver application programs after the sender application's put operation has committed.

Abstract: Various enhancements are made to the architecture of a list processor to facilitate its use in implementing a message queue that is shared by queue managers residing across a multisystem complex. A new list structure control—a program list entry identifier indicator, or PLEIDI—is defined to allow the user to specify whether user-defined entry IDs are used when the list is allocated. A new delete list (DL) command is added that sequentially processes list entries in the order in which they exist on the specified list. A new move list entries (MLES) command provides a performance-optimized means to process an input list of entries. New key comparison functions and list monitoring enhancements have also been added. A new type of key called a secondary list entry key (SLEK) allows the user to specify a secondary key value as a means to identify a list entry.

Abstract: A method and apparatus for implementing a shared message queue using a list structure. A put list is defined comprising a sequence of list entries, each of which corresponds to a message in the queue and has an associated list entry key. Each list entry key corresponding to an uncommitted message falls within an uncommitted key range defining an uncommitted portion of the put list, while each list entry key corresponding to a committed message falls within a committed key range defining a committed portion of the put list. To write a message to the queue, a list entry is added to the put list having a list entry key within the uncommitted key range.

Abstract: The invention relates to communicating message data between application programs, the message data relating to units of work performed by the application programs. A plurality of message queuing subsystems interface to the application programs and are coupled together through a coupling facility. The message data is communicated in shared queues between the message queuing subsystems by means of data structures contained in the coupling facility. The data structures include an administrative structure listing unit of work descriptors describing operations performed by the queuing subsystems on a shared queue. A connection failure between a queuing subsystem and the shared queue is notified to the remaining queuing subsystems connected to the shared queue.

Abstract: Provided are a method, computer program product and system for providing indexed queue support for efficient retrieval of messages from a queue. An index key for expediting message retrieval is assigned to a message when the operation of placing the message on a queue is committed. The index assigned at commit time comprises an attribute (such as a message ID or correlation ID) specified by the sending application program which placed the message on the queue. This deferred assignment of an index key until commit time means that the index key can be used to search for messages having the particular attribute without any possibility of identifying messages for retrieval before the messages have been committed.

Abstract: The invention relates to communicating message data between application programs, the message data relating to units of work performed by the application programs. A plurality of message queuing subsystems interface to the application programs and are coupled together through a coupling facility. The message data is communicated in shared queues between the message queuing subsystems by means of data structures contained in the coupling facility. The data structures include an administrative structure listing unit of work descriptors describing operations performed by the queuing subsystems on a shared queue. A connection failure between a queuing subsystem and the shared queue is notified to the remaining queuing subsystems connected to the shared queue.

Abstract: A method for dynamically assigning and removing task affinity for a resource is disclosed and claimed. A first interrupt handler recognizes a special task interrupt condition which is generated by the hardware. The interrupt condition is generated because a task attempted to execute a special instruction and either a special resource is attached to the central processing unit which issued the special instruction, or a special resource is not attached to the issuing central processing unit, but could be attached to another central processing unit in a central electronic complex. The first interrupt handler then passes control to a second interrupt handler which determines if execution of the current task can continue. If it can, the second interrupt handler creates or reestablishes a special environment and the task is dispatched (either for the first time or again) with a special dynamic affinity to only those central processing units in the central electronic complex that have a special resource attached.