Abstract: Disclosed is a method, system, and program for database query execution. A range of data pages is assigned to each of multiple parallel tasks. For each of the multiple parallel tasks, the range of data pages is mapped to one or more physical partitions, and a data partitioned secondary index partition associated with each of the one or more physical partitions is identified. Each of the multiple parallel tasks is executed to process the database query against the assigned range of data pages using the one or more data partitioned secondary index partitions.

Abstract: Disclosed is a method, system, and program for database query execution. A range of data pages is assigned to each of multiple parallel tasks. For each of the multiple parallel tasks, the range of data pages is mapped to one or more physical partitions, and a data partitioned secondary index partition associated with each of the one or more physical partitions is identified. Each of the multiple parallel tasks is executed to process the database query against the assigned range of data pages using the one or more data partitioned secondary index partitions.

Abstract: Disclosed is a system, method, and program for searching a list of entries. Each entry is comprised of multiple fields. Each field in the entry may include one of a range of possible values for that field. If search criteria is provided for less than all of the fields, then multiple search keys will be generated such that each generated search key includes a search value for each field. The search value for each field for which there are no provided search criteria comprises one of the possible values for that field. A search operation is executed for each of the generated search keys to determine entries in the list that include field values that match the search values in the search key.

Abstract: A method, apparatus, and article of manufacture for a computer-implemented apportioning system. Work is distributed to processors in a multi-processor system. Initially, during bind-time, a scaling factor is determined for each processor. The scaling factor represents relative processing power in relation to each other processor. Then, portions of a total amount of work are distributed to each processor based on the determined scaling factor of that processor and a determined amount of work for an average processor.

Abstract: Disclosed is a system, method, and program for joining a multi-column table and at least two satellite tables. Each satellite table is comprised of multiple rows and at least one join column and each multi-column table is comprised of multiple rows and join columns corresponding to the join columns in the satellite tables. A query including predicates is received. A join predicate column comprises the satellite table and multi-column table join column to which at least one query predicate applies. A determination is then made as to whether there is at least one index on the multi-column table including at least one column for one join predicate column. One index is selected. The ordering of the join predicate columns in the selected index is used to determine the join order of the satellite tables and the multi-column table. The satellite tables and multi-column tables are then joined in the determined join order.

Abstract: A method, apparatus, and article of manufacture for a computer-implemented apportioning system. Work is distributed to processors in a multi-processor system. Initially, during bind-time, a scaling factor is determined for each processor. The scaling factor represents relative processing power in relation to each other processor. Then, portions of a total amount of work are distributed to each processor based on the determined scaling factor of that processor and a determined amount of work for an average processor.

Abstract: The system, method, and program of this invention collects multi-column statistics, by a database management system, to reflect a relationship among multiple columns of a table in a relational database. These statistics are stored in the system catalog, and are used during query optimization to obtain an estimate of the number of qualifying rows when a query has predicates on multiple columns of a table. A multi-column linear quantile statistic is collected by dividing the data of multiple columns into sub-ranges where each sub-range has approximately an even distribution of data, and determining a frequency and cardinality of each sub-range. A multi-column polygonal quantile statistic is collected by dividing the data of multiple columns into sub-spaces where each sub-space contains approximately the same number of tuples, and determining a frequency and cardinality of each sub-space.

Abstract: A method, apparatus, and article of manufacture for a computer implemented query compiler. A query is executed in a computer, the query being performed by the computer to retrieve data from a database stored on a data storage device connected to the computer. The query is received containing at least one variable. At execution time, a value is determined for each variable in the query. A filter factor is estimated using the determined value for each variable. Then, an access path is determined for the query using the estimated filter factor.

Abstract: A method, apparatus, and article of manufacture for an index screening system. A query is executed to access data stored on a data storage device connected to a computer. In particular, while accessing one or more indexes to retrieve row identifiers, index matching predicates in the query are applied to select row identifiers and index screening predicates in the query are applied to eliminate one or more selected row identifiers.

Abstract: A method, apparatus, and article of manufacture for a computer implemented query compiler. A query is executed in a computer, the query being performed by the computer to retrieve data from a database stored on a data storage device connected to the computer. The query is received containing at least one variable. At execution time, a value is determined for each variable in the query. A filter factor is estimated using the determined value for each variable. Then, an access path is determined for the query using the estimated filter factor.

Abstract: The system, method, and program of this invention collects multi-column statistics, by a database management system, to reflect a relationship among multiple columns of a table in a relational database. These statistics are stored in the system catalog, and are used during query optimization to obtain an estimate of the number of qualifying rows when a query has predicates on multiple columns of a table.A multi-column linear quantile statistic is collected by dividing the data of multiple columns into sub-ranges where each sub-range has approximately an even distribution of data, and determining a frequency and cardinality of each sub-range. A multi-column polygonal quantile statistic is collected by dividing the data of multiple columns into sub-spaces where each sub-space contains approximately the same number of tuples, and determining a frequency and cardinality of each sub-space.

Abstract: A method and apparatus for generating static, dynamic and hybrid sparse indices for use with workfiles used by SQL queries in a relational database management system.

Abstract: A relational data base management system includes a query processor that permits consideration of alternative user-specified access paths, which the processor will validate and incorporate into the query execution plan it otherwise generates. The optimizer of the query processor retrieves user-specified data that defines an access path for a query during bind operations. Any access path parameters that are invalid are replaced with processor-selected values.

Abstract: A method, apparatus and article for manufacture for generating static, dynamic and hybrid sparse indices for use with workfiles used by SQL queries in a relational database management system. A workfile and a sparse index structure are temporarily created in the computer during execution of the query by the computer. The workfile stores intermediate relations resulting from execution of a portion of the SQL query, wherein the intermediate relations comprise sorted rows for an inner table referenced in the SQL query. The sparse index structure contains one or more entries indicating at least an approximate location for at least some of the rows in the workfile. As one or more rows from an outer table referenced in the SQL query are retrieved, the entries of the sparse index structure are searched for a closest matching entry for each retrieved row. The sorted workfile is then scanned for a row matching each retrieved row using the closest matching entry from the sparse index structure as a starting position.

Abstract: A system and method for a computer system having a plurality of DBMS providing a coordinating and assisting function. If a DBMS performs a coordinating function, it is referred to as a coordinating DBMS. If a DBMS performs an assisting function, it is referred to as an assisting DBMS. Each coordinating DBMS receives a query from a user application, decomposes the query into multiple parallel tasks, and allocates the parallel tasks to all of the DBMSs in the system. Each assisting DBMS receives one or more parallel tasks from a coordinating DBMS, executes the parallel tasks and returns the results to the coordinating DBMS. The coordinating DBMSs and assisting DBMSs access one or more storage devices. Furthermore, the present invention comprises a system and method for dynamically disabling a parallel mode on the coordinating DBMSs and the assisting DBMSs.