Abstract: There is provided a parallel database system 1. System 1 includes a storage device 2 for maintaining a plurality of rows 3. System 1 also includes a plurality of access modules 4 for accessing in parallel a respectively assigned one or more of rows 3. An interface 5 receives data 6 indicative of a table 7 defined by a selection 8 of rows 3. A processor 9 is responsive to data 6 for selectively designating table 7 to be a single-module table. In this single module table, selection 8 is collectively assigned to an owning one of modules 4, indicated by reference numeral 10.

Abstract: A method, system and computer program for mapping business concepts related to the processing of requests on a database system to database system feature settings is disclosed. Rules limit the requests that will be submitted to the database system for processing and establish workload definitions that can be used to map each request submitted to the database system for processing to database feature settings, based on business concepts associated with each request.

Abstract: A method, database system and computer program are disclosed for performing a temporal join between two temporal database tables. The method includes determining a selected table intersection between a period of interest and a time period value for a selected table row, scanning an inner table for a row that matches the selected table on the join conditions and overlaps the selected table intersection, and determining the remainder time period values from the selected table intersection.

Abstract: A method, database system and computer program are disclosed for optimizing a SQL query, in which the SQL query seeks to aggregate temporal database information. The method includes determining whether two rows of information have a common grouping value, and if so, determining both temporal overlap and temporal non-overlap components of the two rows, aggregating each of the temporal overlap components of the two rows, and separating the temporal non-overlap components of the two rows.

Abstract: A method, computer program and system for regulating the workload of a database system as it processes one or more requests are disclosed. The requests are grouped into workload groups and are processed by one or more of a plurality of subsystems within the database system. Each subsystem has resources. The system has resources. The subsystem resources and the system resources are allocated across the workload groups. The method, computer program and system include monitoring, at a subsystem level, the processing of the requests and adjusting the allocation of subsystem resources to workload groups to achieve a subsystem goal and monitoring, at a system level, the processing of the requests and adjusting the allocation of system resources to workload groups to achieve a system goal. The subsystems are arranged in a hierarchical network.

Abstract: Request processing is optimized. The request has elements. The method, computer program and database system includes selecting an access path for the request taking into consideration a stored actual request element cost, processing the request using the selected access path, producing one or more actual request element costs, and storing the one or more actual request element costs.

Abstract: A method and computer program for clustering a string are described. The string includes a plurality of characters. R unique n-grams T1 . . . R are identified in the string. For every unique n-gram TS, if the frequency of TS in a set of n-gram statistics is not greater than a first threshold, the string is associated with a cluster associated with TS. Otherwise, for every other n-gram TV in the string T1 . . . R, except S, if the frequency of n-gram TV is greater than the first threshold, and if the frequency of n-gram pair TS-TV is not greater than a second threshold, the string is associated with a cluster associated with the n-gram pair TS-TV. Otherwise, for every other n-gram TX in the string T1 . . . R, except S and V, the string is associated with a cluster associated with the n-gram triple TS-TV-TX. Otherwise, nothing is done.

Abstract: 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.

Abstract: A method for retrieving information from a database includes identifying a cylinder. The cylinder includes a plurality of data segments. The method also includes retrieving the plurality of data segments from the cylinder during a single retrieval operation. In addition, the method includes storing the plurality of data segments in a cache.

Abstract: A method, computer system, and database system for automating a business rule in a database are disclosed. One or more database triggers associated with a business rule state machine are enabled and the business rule state machine is initialized.

Abstract: There is provided a method, system and computer program for updating at least one component in a multi-component software application. The method includes receiving application data describing characteristics of the software application, receiving update data describing at least one update applicable to the software application and reviewing the application data and update data to determine whether the at least one update is applied to the software application.

Abstract: A computer-implemented system, method and article of manufacture for managing a plurality of database systems in a domain, wherein each of the database systems are managed by one or more closed-loop system management (CLSM) regulators. A virtual regulator manages the domain, wherein the virtual regulator communicates with the CLSM regulators to monitor the database systems' system conditions and operating environment events within the domain and to provide for dynamic query optimization between the database systems within in the domain based on the system conditions and operating environment events.

Abstract: A method of selecting for use a stored execution plan for a dynamic SQL query within a database system. Respective selectivity values are maintained that are associated with one or more predicates in the dynamic SQL query for respective historical data values. Respective confidence level values are maintained that are associated with one or more of the selectivity values. One or more data values are received with which to execute the dynamic SQL query. Respective selectivity values are calculated for one or more of the predicates in the dynamic SQL query for the received data value(s). The stored selectivity values are compared with respective corresponding calculated selectivity values. A stored execution plan is selected for use on detecting substantial equality between the respective pairs of compared values.

Abstract: In a method, computer program and process for administering the workload of a database system as it executes one or more requests the one or more requests are sorted into one or more workload groups. Each workload group has an associated level of service desired from the database system. The one or more requests are executed in an order intended to achieve the levels of service associated with each of the workload groups. The system resources are assigned to the one or more workload groups as necessary to provide the level of service associated with each workload group. The execution of requests is monitored on a short-term basis to detect a deviation from the level of service greater than a short-term threshold. If such a deviation is detected, the assignment of system resources to workload groups is adjusted to reduce the deviation. Monitoring is also performed on a long-term basis to detect deviations from the expected level of service greater than a long-term threshold.

Abstract: A technique for generating two or more execution plans for an SQL query within a database system. The system has two or more resources. A first resource utilization profile is defined by associating a first set of numerical utilization values respectively with two or more of the resources. The utilization values represent utilization of the resources. A first execution plan is generated that is optimal assuming utilization of the resources specified in the first resource utilization profile. The technique defines at least one further resource utilization profile by associating at least one further set of numerical utilization values respectively with two or more of the resources, the further utilization values representing utilization of the resources. At least one further execution plan is generated that is optimal assuming utilization of the resources specified in the further resource utilization profile(s).

Abstract: A method of and system for extracting time series data from temporal data in a database table is disclosed. The method comprises receiving a request for time series data, the request including information indicative of a period of time to be covered by the request, values sought by the request, time instants at which the values are sought and a precision between consecutive time instants, and creating a temporary table and populating the temporary table with a plurality of time stamps covering the period of time indicated by the request, consecutive time stamps being separated by the precision indicated by the request, and the time stamps specifying the time instants indicated by the request.

Abstract: A method, database system, and computer program for collecting statistics about a table are disclosed. The table includes one or more rows and each row includes a respective value. The method includes creating zero or more histogram buckets. Each histogram bucket includes a width representing a respective range of values and a height representing a count of rows having values in the range of values. The method further includes creating one or more high-bias buckets, each high-bias bucket represents one or more values that appear in a minimum percentage of rows.

Abstract: A method and apparatus performs a partitioned joins of spatial objects in a database system. In one example arrangement, each spatial object is represented by z-cells in a z-ordered space. The z-cells of certain spatial objects are either duplicated or redistributed across multiple partitions in the database system to enable parallel joins of spatial objects.

Abstract: A method, computer program, and system for optimizing the execution of a SQL request on a database system are disclosed. The database system has a state. The request has characteristics and the state has characteristics. The SQL request is parsed to create a logical plan. The logical plan is enumerated into a plurality of physical plans. The plurality of physical plans are costed using current environmental and data demographics of the database system to produce cost information. One of the plurality of physical plans is selected using the cost information and workload profile information to execute the request. Workload profile information includes one or more characteristics of the request and the state of the database system. The request is executed using the selected physical plan to produce results.

Abstract: 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.