International Business Machines Corporation

Craig Alan Friske

James Alan Ruddy

John Marland Garth

Regina J Liu

James Z Teng

Julie Ann Watts

Ka Chun Ng

Binghui Zhong

Laura Michiko Kunioka-Weis

Balakrishna Raghavendra Iyer

Kenneth E Plambeck

Kalpana Shyam

Jay A Yothers

Jerry Mukai

Charles H Lin

Gary Howard Sockut

Cherri M Vidmar

Stephen Walter Turnbaugh

John P Lazarus

Bituin B Vizconde

David Wilhite

Szu-Huey Chuang

Chung-Chia Chang

Gregory L Davoll

Arnold T Banzon

Mohamed H El-Ruby

James Zu-Chia Teng

Akira Shibamiya

Paramesh Sampatrai Desai

Christina Marie Lee

Kathryn Ruth Zeidenstein

Daniel Keith Courter

David Elmer Raiman

Kevin Daniel Gougherty

Dropping of columns from a table with data availability, where the columns in the table are each associated with a column number, includes: executing a statement to drop a given column in the table and deferring an application of the statement until a reorganization of a current data set including the table. When the reorganization of the current data set is performed, the reorganization includes: updating column numbers for columns in each row of the table using a mapping data structure to remove the given column; loading the plurality of data rows with the updated column numbers into a shadow data set; applying to the shadow data set any changes to the table that are concurrent with the reorganization; updating a schema definition of the table with the updated column numbers; and switching the current data set to the shadow data set.

Dropping columns from a table with minimized unavailability

Recovering data to a point in time before pending definition changes are materialized in a relational database management system. One or more definition changes to a database schema are received. Original data base schema attributes are saved as point in time metadata in a catalog table until the one or more definition changes have been materialized. During recovery processing, it is determined for each object being recovered whether the object is being recovered to a point in time prior to which the one or more definition changes were materialized. In response to determining that an object is being recovered to a point in time prior to which the one or more definition changes were materialized, the saved point in time metadata is used for the object in the recovery process.

Point in time recovery support for pending schema definition changes

Recovering data to a point in time before pending definition changes are materialized in a relational database management system. One or more definition changes to a database schema are received. Original data base schema attributes are saved and maintained as point in time metadata in a catalog table until the one or more definition changes have been materialized. During recovery processing, it is determined for each object being recovered whether the object is being recovered to a point in time prior to which the one or more definition changes were materialized. In response to determining that an object is being recovered to a point in time prior to which the one or more definition changes were materialized, the saved point in time metadata is used for the object in the recovery process.

A method, apparatus and program storage device for managing buffers during online reorganization. An adaptive buffer is provided having a dynamically adjustable boundary, the adaptive buffer processes log records and pointers associated with the log records during online reorganization of a database. Adaptive switching is provided between a first and a second task during the processing of data log records and index log records during the online reorganization of the database.

Method, apparatus and program storage device for managing buffers during online reorganization

A method, apparatus and program storage device for determining an optimal number of tasks during reorganization of a database system with memory and processor constraints. The reorganization system identifies memory constraints, identifies processing capabilities and determines a number of reorganization processes and a combination of reorganization processes that provides a minimum reorganization time based upon the identified memory and processing constraints. The identified memory and processing capabilities identify a domain representing a set of rules applicable to the identified memory and processing capabilities. The set of rules of the identified domain are applied to determine an optimal number and combination of reorganization processes that minimizes a reorganization time.

Method, apparatus and program storage device for determining an optimal number of tasks during reorganization of a database system with memory and processor constraints

One or more indexes are built on data (concurrent with manipulation of data) wherein the index build operation is done without restricting the manipulation of data. The index is brought to consistency with the data based upon processing recovery log records to simulate index manipulations during data insert, update, or delete operations.

Method and apparatus for building one or more indexes on data concurrent with manipulation of data

The present invention is related to a method and system for preserving an original table schema for a table in a database system that supports dynamic table schema changes. The method and system includes storing the original table schema for the table in a designated table prior to performing a schema change on the table. By storing the original table schema in the designated table, a backup copy of the table that includes rows which are not self-describing can be used for data recovery.

Method and system for preserving an original table schema

A reorganizer utility performs an online reorganization of a database that provides applications with concurrent access to data during an iterative process of log apply operations to a shadow version of the data. The reorganizer continues this iterative process of log apply operations until an estimate of an elapsed time necessary to complete a last iteration is less than or equal to a user-specified maximum length of time that read-only (RO) access may be provided to the data. When this threshold is reached, the reorganizer performs the last iteration, which includes draining all applications making modifications to the data; allowing read-only access to the data, performing log apply operations against the shadow version of the data, and then switching all of the applications to the shadow data.

Method for estimating the elapsed time required for a log apply process

A technique for identifying changes in a data store connected to a computer. Initially, one or more interval changes are measured. Each interval change indicates an amount of change in the data store at an interval. Next, a data store change is estimated that indicates an amount of change in the data store across all of the intervals using each interval change.

Method of estimating an amount of changed data over plurality of intervals of time measurements

A method and apparatus for online reorganization of a database which does not prevent a process from accessing the database during the data reorganization. The invention uses a non-blocking drain to lock on a database, unloads a copy of the data contained in the database, reorganizes the copied data, loads the reorganized data into a shadow location, applies log records to the shadow location data so that the reorganized data may be adjusted for any changes to the database after the data was copied and reorganized, and then replaces the data in the database with the reorganized data. The non-blocking drain does not prevent other requests on the database from being processed while the reorganization lock is in place, except briefly when the reorganized data replaces the data in the database.

Non-blocking drain method and apparatus for use in processing requests on a resource

A method, apparatus, and article of manufacture for a computer-implemented repartitioning system. Data is repartitioned in a database stored on a data storage device connected to a computer. First, it is detected that a partitioning scheme for the data has been altered. Next, partitions that would be affected by the altered partitioning scheme are identified. Then, the identified partitions are reorganized based on the altered partitioning scheme.

Repartitioning data

Non-blocking drain method and apparatus used to reorganize data in a

A system for creating a static data compression dictionary adapted to a hardware-based data compression architecture. A static Ziv-Lempel dictionary is created and stored in memory for use in compressing database records. No data compression occurs during dictionary construction. A fixed-size Ziv-Lempel parse-tree is adapted to database characteristics in one of two alternate ways. First, the parse-tree is overbuilt substantially and then pruned back to a static size by eliminating the least recently used (LRU) nodes having the lowest use count. Alternatively, the parse-tree is built to a static size and thereafter selected nodes are replaced with new nodes upon database sampling. This node recycling procedure chooses the least-useful nodes for replacement according to a use count and LRU strategy while exhausting the database sample. The pruned Ziv-Lempel parse-tree is then transformed to a static dictionary configuration and stored in memory for use in a hardware-based database compression procedure. Completion of the static dictionary before starting data compression eliminates the initial compression inefficiencies well-known for the Ziv-Lempel procedure. The parse-tree construction is enhanced by initializing the tree with NULL and DEFAULT sequences from database definitions before examining any data.

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San Jose, CA, United States of America

Craig Alan Friske