Abstract: Techniques for accessing a parallel database system via an external program using vertical and/or horizontal partitioning are provided. An external program to a database management system (DBMS) configures external mappers to process a specific portion of query results on specific access module processors of the DBMS that are to house query results. The query is submitted by the external program to the DBMS and the DBMS is directed to organize the query results in a vertical or horizontal manner. Each external mapper accesses its portion of the query results for processing in parallel on its designated AMP or set of AMPS to process the query results.

Abstract: Techniques for finding a column with column partitioning are provided. Metadata for a container row is expanded to include information for searching ranges of partitioned column values. The metadata identifies offsets to specific ranges and specific columns within a specific range. The offsets also identify where compressed data for a desired column resides. Thereby, permitting partitioned columns having compressed data to be located without being decompressed and decompressed on demand as needed.

Abstract: Demand Chain Management (DCM) refers to a suite of analytical applications for retail business, that provides retailers with the tools they need for product demand forecasting, planning and replenishment. The reliable development and user-friendly interface of DCM applications ensures improved customer satisfaction, increased sales, improved inventory turns and significant return on investment. The present subject matter provides a self-contained reusable smart cache component for DCM development and interface. The smart cache component gives a DCM developer the ability to automatically have a configurable amount of information temporarily stored in readily available memory on an application server. The information can be retrieved in a high speed fashion without the need for additional calls to the original location of the information.

Abstract: A database system may include a storage array including a plurality of storage devices configured to store database data. The database system may further include a processor in communication with the memory device. The processor may be further configured to determine usage frequency of the database data. The processor may be configured to select a subset of the database data for compression based on the usage frequency. The processor may be further configured to perform the compression of the selected subset of the database data. A method and computer-readable medium may also be implemented.

Abstract: A computer running a database system receives one or more queries, each query comprised of parallel threads of execution working towards the common goal of completing a user request. These threads are grouped into a schedulable object called a task group. The task groups are placed within a specific multiple tier hierarchy, and database system resources allocated to the task groups according to their placement within the hierarchy. Beginning with the top tier of the hierarchy, resources remaining after allocations to each task group within a tier are passed to the next lower tier for allocation.

Abstract: Techniques for parallel frequent sequential pattern detection are provided. A sequence database is split into separate datasets and each node is given a specific dataset to resolve specific frequent items occurring in its specific dataset based on counts. Then, each node groups its item frequent items into “n” (varying) length sequences representing sequential patterns present in the original sequence database. The nodes process in parallel with one another and collectively produce a complete set of the sequential patterns defined in the original sequence database.

Abstract: A full bisection bandwidth network, having a plurality of nodes and a plurality of paths among the nodes, is divided into a plurality of Virtual Local Area Networks (“VLANs”) by assigning paths to the VLANs such that each VLAN satisfies a spanning tree protocol and all paths are active in at least one VLAN.

Abstract: A method, system, and computer program are disclosed. Statistics are read from a data dictionary on a target system. The statistics include statistics for a table in a database in the target system. The statistics are exported to a test system separate from the target system. A command is received to use the statistics in emulation. In response the statistics are copied to a cache in the test system and the target system is emulated on the test system using the statistics in the test system's cache.

Abstract: A database system may include an array of storage devices configured to store a plurality of database tables and a plurality of histograms. Each histogram may correspond to one or more columns of a database table. The database system may further include a processor in communication with the storage device. The processor may receive an indication that a histogram is to be rebuilt, wherein the histogram has a first number of intervals. The processor may determine at least one condition associated with a distribution of column values of at least one column in the histogram. The processor may determine a second number of histogram intervals based on the at least one condition. The processor may rebuild the histogram to include the second number of intervals. A method and computer-readable medium may also be implemented.

Abstract: A system, method, and computer-readable medium for grouping of database object access counts per processing module in a parallel processing system. Each processing module manages an intermediate cache allocated thereto that stores database object access counts local to the respective processing module. The processing modules are configured in a hierarchical configuration. The intermediate caches managed by the processing modules at the lowest level of the configuration are forwarded to a parent processing module and merged with the intermediate cache allocated to the parent processing module. A root processing module merges the intermediate caches received from one or more parent processing modules with the root processing module's intermediate cache to generate a final cache. An objects access count data structure is then generated by the root processing module.

Abstract: A disk-error detection system may include a storage array having a plurality of storage disks configured to store data. The disk-error detection system may include a processor in communication with the storage disks. The processor may detect presence of a media error in a storage disk from the plurality of storage disks during a read operation of the data stored on the storage disk. The processor may perform a media-error detection scan of a predetermined portion of the storage disk in response to the detection of the media error. The location on the storage disk of the predetermined portion of the storage disk may be based on location of the media error on the storage disk. A method and computer-readable medium may also implement disk-error detection.

Abstract: A database system may implement compression management of tables in the database system. The compression management may include determination of a pattern of usage of various database tables in the database system. Based on this pattern of usage, the database tables may be selected as candidates for compression or decompression at the appropriate time. In one example, the pattern of usage may be based on the contents of a query log of the database system. The compression management may also include evaluation of various compression strategies to apply to a candidate database table. Each compression strategy may be evaluated to determine if application to a database table or a portion of the database table would be beneficial based on various conditions. The compression management may also include consideration of each available compression strategy to be applied solely or in combination with one another.

Abstract: A computer-implemented method, apparatus and article of manufacture for optimizing a database query. Resource usage of one or more resources of the computer system are monitored. A condition code representative of the monitored resource usage is stored. A cost model is modified using the stored condition code. A query execution plan is generated for the database query using the modified cost model. The query execution plan is then executed in order to retrieve data from a database stored on the computer system, wherein the retrieved data is presented to a user for subsequent use and analysis.

Abstract: Divisions by numbers that are not divisible by two (2) can be performed in a computing system based on a summation that estimates and/or approximates the reciprocal of the dividing number or denominator value. By way of example, dividing by three (3) can be calculated based on a summation that approximates or estimates one third (?) represented as the sum of a selected group of the inverses of the powers of two (2) in a pattern, namely the sum of: ¼, 1/16, 1/64, 1/256, . . . ). Applications of the division techniques are virtually unlimited and include memory mapping of global memory addresses to memory channel addresses by dividing a global memory address into the number of memory channels, allowing memory mapping to be performed in an efficient manner even for large memory spaces using a number of memory channels that are not divisible by two, including prime numbers.

Abstract: A method for facilitating join operations between a first database table and a second database table within a database system. The first database table and the second database table share at least one common index column. The method includes creating a new index column in the second database table that is populated with a limited number of distinct calculated values for the purpose of increasing the overall number of distinct values collectively assumed by the columns common between the two tables. An intermediate table is created, the intermediate table including the common columns of the first database table, the second database table, and the new index column. An index is defined of the intermediate table to be the column(s) common between the first and second tables. An index is defined of the second table to be the column(s) common between the first database table, the second database table and the new index column.

Abstract: A memory channel can be divided into two or more memory sub-channels, wherein each one of the memory sub-channels includes two or more memory components configured to store data made accessible on that memory sub-channel, and wherein the two or more memory components in each one of the memory sub-channels are respectively connected via at least one transmission line and can be individually accessed (addressed) on their associated sub-channel.

Abstract: Data partitions are assigned to reducer tasks using a cost-based and workload balancing approach. At least one of the initial data partitions remains unassigned in an unassigned partitions pool. Each reducer while working on its assigned partitions makes dynamic run-time decisions as to whether to: reassign a partition to another reducer, accept a partition from another reducer, select a partition from the unassigned partitions pool, and/or reassign a partition back to the unassigned partitions pool.

Abstract: A query is executed on a multi-database system. The multi-database system includes a first system database and a second system database. The query is partially executed on a first system database by generating a spool. It is determined that it is more efficient to store the spool on the second system database than to store the spool on the first system database, and in response the spool is stored on the second system database. The query execution is continued by accessing the spool on the second system database, completing execution of the query to produce a result, and storing the result.

Abstract: A database system comprises a processing module, and a storage device communicatively coupled with the processing module and allocated thereto. The storage device stores a base table allocated to the processing module. The processing module receives a database query from a client computer system, and generates a spool based upon a number of columns of a table, and partitions at least one column of the spool based upon the database query received from the client computer system.

Abstract: Streaming data is populated to an in-memory data table and a continuous query is executed against an in-memory data table using a database interface to perform analytical operations on the populated in-memory data table. Results from the analytical operations performed are streamed to consuming applications.