Ncr Corporation

Teradata Us, Inc.

Teredata, Us, Inc.

J Mark Morris

Bhashyam Ramesh

O Pekka Kostamaa

Todd A Walter

Eric M Shank

Methods, computer programs, and database systems for protecting one or more database objects are disclosed. The methods include designating one or more database objects for protection and characterizing one or more data storage units by a set of dimensions. The method include, for one or more database objects designated for protection: selecting one or more data storage units to store protection information for the database object based on one or more dimensions, and storing protection information in the one or more selected data storage units.

Object-level mirroring

A database system receives a transaction that selects values of a column of a first table based on one or more conditions, the column in the first table being according to a first data type. The database system transforms the first data type to a second, different data type. The selected values of the column according to the second data type are stored in the second table.

Transforming a data type of a column in a table

Methods, computer programs, and database systems for performing a database query to join a column A and a column B on an inequality condition are disclosed. A database includes value-count indexes for columns A and B. Minimum and a maximum values for A and B are determined, using the value-count indexes for A and B, respectively. The method includes defining three or more sets of values in A and B, relative to the minimum and maximum values for B and A, respectively. The method includes generating one or more Cartesian products between values in A and B. The database query is performed on a set of values in A and a set of values in B to generate a partial query result. The method includes merging one or more Cartesian products and the partial query result.

Dynamic partition enhanced inequality joining using a value-count index

Methods, computer programs, and database systems for performing a database query to join two or more tables on a condition are disclosed. Each table includes one or more join columns. Each of the join columns includes zero or more join-column values. The method includes excluding join-column values that do not satisfy the condition, using one or more value-count indexes and performing the database query on non-excluded join-column values.

Dynamic partition enhanced joining using a value-count index

A database system receives a transaction specifying one or more conditions to apply to a first table, and inserts data selected in the transaction into a second. The database system further generates a value list used for compressing a column of the second table, where generating the value list comprises one of inheriting entries of the value list from another value list associated with the first table, and deriving the value list based on the one or more conditions to apply on the first table.

Compressing data stored in an intermediate or result table of a database

Methods, computer programs, and database systems for performing a database query that includes a join on an equality condition are disclosed. The method includes defining two or more first-table partitions and two or more corresponding second-table partitions. The method includes performing the join on the first-table partition and the second-table partition, storing the result, and merging the results.

Dynamic partition enhanced joining

A method, computer program, database system and data structure are disclosed for compressing a decimal type field in a database including one or more tables. Each of the one or more tables includes one or more rows. Each of the one or more rows includes an instance of the decimal type field. Space is allocated in one of P amounts to an instance of the decimal type field in a row, the amount being chosen based on the size of the value being stored in the instance of the decimal type field. One or more presence bits are set in the row to identify the amount of space allocated.

Compressing decimal types

A method, computer program, and computer system are disclosed for managing data corruption identified by an application in a storage subsystem. Data requested of the application by a process is copied from a primary storage device in the storage subsystem to a memory. A data integrity check is performed on the data stored in the memory. If the data integrity check succeeds, the data is provided from the application to the process. If the data integrity check fails: the data requested by the process and stored on the primary storage device in the storage subsystem is identified; the data requested by the process and stored on a redundant storage device in the storage subsystem is identified; the data stored in the memory, the identified data stored on the primary storage device, and the identified data stored on the redundant storage device are compared as the first, second, and third copies, respectfully; and at least one of a group of instructions is chosen to be transmitted from the application to the storage subsystem based at least in part on the comparison of the first, second, and third copies.

Method and system for managing detected corruption in stored data

Detecting data corruption includes receiving one or more blocks of data to be written to a storage device, selecting a portion of the data in the blocks (e.g., one or more bytes or data words), applying a rule to derive information characterizing the selected portion of data (e.g., calculating a checksum for the for the portions of data selected from the block to be written), and storing this information. After the data has been written to the storage device, the store information is used in deciding whether the data has been corrupted.

Detecting and correcting errors in data

A set of storage disks includes a mirrored pair of disks. Each disk in the pair includes a mirror copy of data stored on the other disk in the pair. For each of the disks in the pair, the data forming the mirror copy is physically located between the center of the disk and the data that is mirrored on the other disk.

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Poway, CA, United States of America

J Mark Morris