International Business Machines Corporation

Other

Shawfu Chen

Robert O Dryfoos

Allan Feldman

David Y Hu

Peter Grimm Sutton

Mei-Hui Wang

Jason A Keenaghan

Peter A Lewis

Alice M Williams-Obleton

Adris E Hoyos

John M Tarby

Kevin T Jones

Bernard Klos

Aleksandr Krymer

Mark Richard Gambino

Wei-Yi Xiao

Masashi E Miyake

Ric C Hung

A method, system, method and computer program product for retrieving data. Records are retrieved from a hierarchical database. The records are categorized into a plurality of record types. Each record comprises a unique identifier field. A record map contains zero or more entries. Each entry comprises an identifying value, data from at least one record and a set of Boolean flags. Each flag corresponds to a record type. A computer iterates over the retrieved records. Data from each record is stored at an entry in the record map having an identifying value equal to the value included in the unique identifier field of the record. Moreover, the flag in this entry which corresponds to the record type of the record is set. Inner joins and outer joins are then performed using the contents of the record map.

Performing an efficient implicit join of multiple mixed-type records

Techniques for replicating modified data to a hierarchical database. A first list comprises records included in a set of records before at least one modification thereto. A second list comprises records included in the set of records after the at least one modification thereto. For each pre-modification record included in the first list and each post-modification record included in the second list having equal identifying values, a target record at the database and having a matching identifying value is modified. Specifically, if both records include corresponding indexes, information about a structure pointed to by the pre-modification record is removed from an index included in the target record, and information about a structure pointed to by the post-modification record is added to the index. If neither record includes an index, the target record is modified to contain at least one changed value included in the post-modification record.

Accessing a hierarchical database using service data objects (SDO) via a data access service (DAS)

A plurality of batch lists are maintained by a channel in order to improve the efficiency of the channel in performing messaging between a sender and a receiver. For example, a Next Batch list is used to prefetch messages to be sent to the receiver from the sender; a Current Batch list includes the messages currently being transmitted to the receiver or waiting confirmation; and an Acknowledged Batch List includes the messages confirmed by the receiver. This allows the functions of prefetching messages, sending messages and deleting confirmed messages to be performed in parallel.

Method, system and program storage device for accessing memory to perform messaging using a channel coupled to a sender and a receiver

A method for triggering message queue applications, comprising performing a first trigger process, the first trigger process including: a first application evaluating a queue for a trigger message; the first application determining whether a second trigger process is already being performed for the queue; and the first application invoking a second application where the invoking is in response to the trigger message.

System and method for triggering message queue applications

Performance of channels used in communicating between senders and receivers

A structure and method is provided for optimizing memory resources, by establishing a history file for recording data processing criterion. The history file is then recorded in a first memory. Information either stored in the first memory or scheduled to be stored in the first memory can then be selectively reallocated and stored in an alternate memory. All or portions of the reallocated information can then be restored back to the first memory subsequently, with reference to the history file.

Structure and method for efficient management of memory resources

A highly available, high-performance memory queue. Locking of the queue is minimized in order to provide a highly available queue and to improve performance of the queue. Multiple updates of the queue can occur under a single lock. Further, messages of the queue are persistent. A time-initiated checkpointing process, as well as the storing of message information on a recovery log, ensures the persistence of the queue messages.

High-performance memory queue

Memory resident queues are monitored at predefined time intervals. When the monitoring indicates that a particular queue is not being serviced at a desired level, then action is taken to sweep one or more messages from the queue. The sweeping of the messages frees up system resources associated with the messages, thus allowing other tasks to be serviced. If, after the sweeping, it is determined that the queue can handle additional messages, then one or more messages are placed back on the queue.

Managing memory resident queues to control resources of the systems using the queues

A real-time vehicular traffic flow display system employs groups of monitor stations positioned at spaced-apart locations along vehicular roadways, to sense the speed of traffic flow on a given portion of a route. Individual section stations each serve a sequential group of different monitor stations. Each monitor station senses the speed of vehicular traffic a given road portion and transmits corresponding information to an associated section station; each section station processes the received signals, and transmits them to display stations on board vehicles in addition to sending the signals to an optional geographic area central station. The signals transmitted to vehicles present information concerning traffic speed for each monitored portion of a road in addition to identifying the road portion; traffic speed information is processed to identify predetermined ranges of average speed in selected colors. Each vehicle station includes a Global Positioning System (GPS) receiver and visual display device with access to both the GPS including a database of local area road maps for display. All portions of each monitored route on a displayed map are shown in a color corresponding to the average speed of traffic monitored on the corresponding route portion. The current position of the vehicle station is shown on the map, and a 'preferred' route from that location to an optionally selected destination is highlighted; both functions are accomplished in accordance with known GPS technology. An optional geographic area central station stores information not usually available in the on-board vehicle station, such as wide-area maps, and also receives traffic condition signals from various section stations including those beyond the range of the vehicle station. The central station correlates these two sources of information and makes the combined results available for separate access by users of the system.

Traffic flow and route selection display system for routing vehicles

When a processor becomes inactive, queues resident in the memory of that processor become inaccessible. Thus, in order to access those queues, an active processor takes over ownership of one or more of the inaccessible queues. Each queue may be rebuilt prior to its take over to ensure that it has up-to-date information.

Reconstructing memory residents queues of an inactive processor

A method and apparatus for switching messages from a primary message channel to a secondary message channel in a message queuing system in which messages are placed in a first transmission queue of a local system for transmission to a remote system via a primary message channel. A local queue manager continuously checks to see whether a high water mark has been reached in the first transmission queue, indicating an apparent failure in the primary message channel. On determining such an apparent failure in the primary message channel, the queue manager determines whether the secondary message channel is associated with the first transmission queue. If so, the queue manager activates the secondary message channel to serve said first transmission queue. If, on the other hand, the secondary message channel is associated with another transmission queue, the queue manager transfers messages already in the first queue to the other queue and redirects any new messages intended for the first queue to the other queue. If the other transmission queue was previously empty, the secondary message channel is activated by a trigger to serve the other queue.

Method and apparatus for switching messages from a primary message channel to a secondary message channel in a message queuing system

A method for a non-disruptive TCP connection switch is introduced that allows the re-establishment of communications between a remote host and a new host when the host originally in processing communication with the remote host takes an outage. The present invention particularly relates to loosely coupled environments connecting to a TCP/IP network. The method involves three important steps of initialization, during which all hosts and remote hosts are identified by a communication box; failure detection step during which a host outage is detected by the communication box; and re-registration step during which the communication box provides and re-establishes processing connection between the remote host and a new host replacing the initial failing host.

Method for a non-disruptive host connection switch after detection of an

A system for maintaining a non-disruptive connection between a local host and a remote host is introduced that allows the re-establishment of processing communications between the remote host and a new host in case the first host originally in processing communication with the remote host experiences an outage. The present invention particularly relates to loosely coupled environments connecting to a TCP/IP network. The system uses a communication box or an offload frontend box for holding all socket associations between the remote host and the local hosts. Each socket connection associates the remote host to an application being run on the local host but maintained by the communication or the offload frontend box. The offload frontend box detects a host outage through its channel connectivity and holds all processing and communication data related to the failing host until a new connection is established between a second host and the remote host, at which time the box transfers all such data to the second replacing host.

Loosely coupled system environment designed to handle a non-disruptive

A system and method for allowing communications sessions to be established between two or more computer processors and a remote terminal in a communications network where only one host to terminal session may be created. The system allows processors in a loosely coupled processor complex to determine whether another of the processors has an existing communications session with the requested remote device. If so, any new request for a communications session with that remote device will be routed through the processor with the established link. The interprocessor routing uses service transaction programs within each of the processors in a loosely coupled complex to establish the required communications sessions and to serve as an intermediary for passing messages between the requesting host and the remote device.

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New Milford, CT, United States of America

Shawfu Chen