International Business Machines Corporation

Vern Lee Watts

Harley A Beier

Richard G Hannan

Shyh-Mei Fang Ho

Richard C Schneider

Jack Chiu-Chiu Yuan

Steve T Kuo

Judy Y Tse

David Wayne Moore

Mark Neal Ziebarth

Karen Alicia Ranson

Dean Lynn Grover

Steven Michael Bock

Thomas Phillip Bridges

Jerome Joseph Zentner

Claudia Si-man Ho

Sidney Kornelis

Percy Tzu-jung Li

Jimmy Paul Strickland

Gregory Walter Vance

Ronald L Obermarck

Donald Prentiss Terry

Harrison Scofield

Takeshi Fukumoto

Joaquin Ramirez

Lawrence Edward Sullivan

Robert Frederic Kern

Merle R Beghtel

Charles Alexander Goodwyn, Jr

A method, apparatus, and program for reorganizing a database while concurrently providing access to the database for updates. In an exemplary embodiment of the invention, an on-line reorganization facility (ORF) uses index data-spaces that point to other data-spaces, referred to as data data-spaces, to efficiently track and coordinate information about the data-elements in an original data-space operated upon by a reorganization process. A relative base address of a data-element in an index data-space can be derived from a relative base address of a data-element in an original data-space, and vice versa. An index data-space data-element contains a location of a data-element in a data data-space that tracks change information related to a corresponding data-element in the original data-space. Tracked changes are later applied to the newly reorganized data-space to assure consistency and integrity of the data. Tracked changes include the location in the original data-space where the change occurred and a flag indicting the type of change.

Method, apparatus, and program for capturing data changes utilizing data-space tracking

A program for reorganizing information in a computer system while concurrently providing access to the information for updates. In an exemplary embodiment of the invention, an on-line reorganization facility (ORF) uses index data-spaces that point to other data-spaces, referred to as data data-spaces, to efficiently track and coordinate information about the data-elements in an original data-space operated upon by a reorganization process. A relative base address of a data-element in an index data-space can be derived from a relative base address of a data-element in an original data-space, and vice versa. An index data-space data-element contains a location of a data-element in a data data-space that tracks change information related to a corresponding data-element in the original data-space. Tracked changes are later applied to the newly reorganized data-space to assure consistency and integrity of the data. Tracked changes include the location in the original data-space where the change occurred and a flag indicting the type of change.

Program for capturing data changes utilizing data-space tracking

A system for satisfying a request from a client for a send-then-commit transaction includes a front-end information management system (IMS) server. Shared message queues (SMQ) communicate with the front-end IMS server and plural back-end IMS. The front-end IMS server receives the request from the client and transmits the request to the SMQ. A back-end IMS server accesses the SMQ and generates a transaction output in response to the request. The back-end IMS server transmits the result to the front-end IMS server and the front-end IMS server interfaces with the client to communicate the response thereto. The back-end IMS server and front-end IMS server operate in separate system images, but work together in a resource recovery services (RRS) environment to commit or backout the transaction output.

System and method for processing transactions in a multisystem database environment

A method of reorganizing a database while concurrently providing access to the database for updates. In an exemplary embodiment of the method, an on-line reorganization facility (ORF) uses index data-spaces that point to other data-spaces, referred to as data data-spaces, to efficiently track and coordinate information about the data-elements in an original data-space operated upon by a reorganization process. A relative base address of a data-element in an index data-space can be derived from a relative base address of a data-element in an original data-space, and vice versa. An index data-space data-element contains a location of a data-element in a data data-space that tracks change information related to a corresponding data-element in the original data-space. Tracked changes are later applied to the newly reorganized data-space to assure consistency and integrity of the data. Tracked changes include the location in the original data-space where the change occurred and a flag indicting the type of change.

Method of capturing data changes utilizing data-space tracking

Methods and apparatuses are described that use index data-spaces that point to other data-spaces referred to as data data-spaces to efficiently associate temporary information with data-elements in a data-space. An original data-space is divided into data-elements of fixed size, based upon application requirements for the resolution at which temporary information is to be associated with data in the original data-space. The relative base address of data-elements in an index data-space can be ascertained from the relative base address of their corresponding data-element in an original data-space, and vice versa. Each index data-space data-element can be populated with a pointer to a data data-space data-element that can be populated with information relevant to the associated original data-space data-element. Index data-space and data data-space memory requirements are optimized to meet application requirements.

Data-space tracking with index data-spaces and data data-spaces

A throttling specification is received by a computer task to direct the computer task's usage of critical computer resources, such as CPU cycles. The computer task comprises units of work, and the elapsed time of each unit of work is calculated as each unit of work completes. Upon the completion of one unit of work, a suspension time is calculated based at least partially on the throttling specification and the elapsed time corresponding to the completed unit of work. Prior to initiating the next unit of work for the computer task, the computer task is suspended for the calculated suspension time. In this manner, other important computing tasks operating in the computer system have access to critical computer resources during the suspension period. Even though the computer task may be given the highest possible priority to ensure a timely and predictable completion, total monopolization of critical computer resources is avoided.

Method, computer program product, and system for a self-throttled computing task

An on-line reorganization facility (ORF) uses index data-spaces that point to other data-spaces, referred to as data data-spaces, to efficiently track and coordinate information about the data-elements in an original data-space operated upon by a reorganization process. A relative base address of a data-element in an index data-space can be derived from a relative base address of a data-element in an original data-space, and vice versa. An index data-space data-element contains a location of a data-element in a data data-space that tracks change information related to a corresponding data-element in the original data-space. Tracked changes are later applied to the newly reorganized data-space to assure consistency and integrity of the data. Tracked changes include the location in the original data-space where the change occurred and a flag indicting the type of change.

Capturing data changes utilizing data-space tracking

A fuzzy data record pointer is utilized for identification of both a target file and a target data record within the target file. A target data record is accessed from a target file, selected from a set of N related files, utilizing a fuzzy data record pointer (&ldquo;fuzzy&rdquo;, as used herein, means that the data record pointer need not be coincident with the actual data record address). A modulus for the data record pointer divided by N is computed. This modulus is used to select the target file. A data record address is computed for the target data record utilizing the data record pointer and modulus. In this manner a fuzzy data record pointer is utilized to determine both the target file from a set of N related files and the target data record to be accessed within the target file.

Method, computer program product, and system for file and record selection utilizing a fuzzy data record pointer

A method and apparatus for merging log data for recovering one or more database data sets to any point-in-time in a single pass of log data sets. Using disaster recovery technology, the invention may be implemented to provide a method to reduce the time that a broken database is unavailable by processing recovery input data in parallel and recovering multiple database data sets, including areas, simultaneously. The invention reduces operational complexity and resource constraints experienced by IMS customers trying to recover database data sets especially in a data sharing environment. The invention simplifies the recovery process by eliminating both the need for change accumulation and the need to run separate recovery jobs for each database data set requiring recovery, thereby reducing the impact of recovery on system resources.

Database recovery to any point in time in an online environment utilizing disaster recovery technology

A method, apparatus, and article of manufacture for accessing a database. A hierarchical database system is modeled into an objects framework, wherein the objects framework corresponds to one or more application views, database definitions, and data defined and stored in the hierarchical database system. The objects framework also provides mechanisms for accessing a relational database system, wherein the objects framework provides industry-standard interfaces for attachment to the relational database system. Transactions from an application program for both the hierarchical database system and the relational database system are processed through the objects framework using message queue objects.

Object-oriented programming model for accessing both relational and hierarchical databases from an objects framework

The invention is an optimistic locking mechanism which allows Internet access to a database while maintaining data integrity in a stateless web environment. One embodiment of the invention incorporates a conventional IMS residing on a host computer and includes a generic transaction module which retrieves original data segments from the an IMS database in response to a search request from a web user. This embodiment of the invention further includes a server-side interface module for duplicating the original data segment into identical lines of data segments. One data segment may be updated by a web user whereas the other data segment remains constant and serves as a reference of the original state of the data segment. Both data segments are transmitted to a web user who may make changes to one data segment but not the other. Both data segments are returned, and the generic transaction module compares the state data segment to a current data segment to determine if the web user updates were based on the current state. If so, the IMS is updated to reflect the web user updates. If the web user updates were not based on the current state, the data segments are updated to reflect the current state and are then retransmitted to the web user. In this manner, a web user is allowed to update only data segments which are current, thereby maintaining integrity of the database.

Apparatus, method, and article of manufacture for client-side optimistic locking in a stateless environment

A method and apparatus to synchronize recovery logs transmitted to a remote site for recovering related databases having different logical structuring. In one embodiment, the related databases are a hierarchial structured database such as IMS and a relational structured database such as DB2.

Synchronizing recovery log having time stamp to a remote site for

The system, method, and program product of this invention allows a database management system to internally use direct and indirect pointing to locate targeted data elements that are logically related to another data element or are a target of a secondary index. By using direct and indirect pointing, the number of steps involved in a reorganization of the database can be reduced. After a reorganization, the database management system does not go back, in a separate process, to update all of the direct pointers that have pointed to segments that have moved as a result of the reorganization. Instead, the direct pointer is updated, by using the indirect pointer, only upon a first reference to the targeted data element that has moved. As such, each data element, that points to a targeted data element, has a direct pointer associated with it having a unique identifier of the targeted data element, assigned by the DBMS at the time a data element is created, a partition id of the targeted segment, a reorganization number, and a pointer to a location of the targeted data element. Each targeted data element has an entry in an indirect index where the unique identifier is the key into the index. Each entry is updated, with a new location, whenever the targeted data element is moved. The DBMS also maintains, in memory, a current reorganization number for each partition. Upon reference to a targeted element, the reorganization number in memory is compared with the reorganization number in the direct pointer. If they match, the direct pointer is used to locate the targeted element. If they do not match, the indirect index is used by indexing into it by using the unique id in the direct pointer. The current location and current reorg number from the indirect index are used to update the direct pointer. The direct pointer can then be used, directly, to locate the targeted data element on subsequent references until a next reorganization involves the targeted data segment.

System, method, and program for using direct and indirect pointers to

The system, method, and program product of this invention allows a database management system to internally use direct and indirect pointing to locate targeted data elements that are logically related to another data element or are a target of a secondary index. By using direct and indirect pointing, the number of steps involved in a reorganization of the database can be reduced. After a reorganization, the database management system does not go back, in a separate process, to update all of the direct pointers that have pointed to segments that have moved as a result of the reorganization. Instead, the direct pointer is updated, by using the indirect pointer, only upon a first reference to the targeted data element that has moved. Each targeted data element has an entry in an indirect index where a unique identifier of the targeted data element is the key into the index. The indirect index has two direct pointer slots. Which pointer slot is used by the DBMS is determined by the odd/even reorganization number. For each reorganization, the DBMS alternates between the two portions of the indirect index to update the appropriate one of the two pointers with a new location whenever the targeted data element is moved. As a result, the indirect index contains the most recent update and the most recent previous update. If the reorganization fails, the most recent previous pointer is used to find the location of the targeted data element. Consequently, as the reorganization process is proceeding, the update to the assigned slot for the new reorganization number can be made without logging and without involving unnecessary overhead associated with maintaining direct recoverability of the keyed data records.

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Los Altos, CA, United States of America

Vern Lee Watts