International Business Machines Corporation

Dermot Flaherty

Jeffrey Mark Nick

David Arlen Elko

David Harold Surman

Stephen James Hobson

Douglas W Westcott

Paul Kettley

Peter Siddall

Richard Dievendorff

James H Warnes

Paul Hopewell

Robert Daniel Millar

Stephen Richard Walker

David James Fisher

Stephen James Todd

A messaging handling system implements the well-known Two-Phase Commit protocol (comprising prepare and commit operations) to store messages related to transactions in a repository, but enforces message ordering. The commit operation is divided into two phases: a commit phase and a release phase. Prepare requests are implemented conventionally. Commit requests are implemented by immediately executing the commit phase of the operation, but delaying release of the message for reading from the repository until all prepare requests received prior to an instant request have released. In this manner, message ordering is preserved, while allowing use of conventional two-phase commit protocol processing.

Message ordering in a messaging system

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&#x2014;a program list entry identifier indicator, or PLEIDI&#x2014;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.

Method and apparatus for processing a list structure

A data processing arrangement () and method for fuzzy backup and restore of MQSeries shared queues held in coupling facility list structure (). Periodically backups are taken of the data held in the CF list structure by backing up messages in the sequence uncommitted puts (), committed puts (), uncommitted gets () and expired messages (), whereby all messages may be backed up in the backup means except for exceptions which are recorded in the record log. In the event of media failure of the coupling facility, data can be restored by restoring messages in the sequence restoring messages from the backup means (), replaying messages from the record log means () and determining final disposition of messages from replay of the record log means (). This provides the advantage of allowing the number of log records written to be reduced.

Data processing arrangement and method

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.

Method and apparatus for implementing a shared message queue using a list structure

A data processing system () and method for creating a fuzzy backup () only of objects older than a predetermined threshold, and restoring from the fuzzy backup and from a record log () replayed from a time equal to the predetermined threshold before the fuzzy backup start time. This provides advantages of reduced resource cost for the fuzzy backup and reduced restore time.

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Southampton, United Kingdom

Dermot Flaherty