Abstract: A method, apparatus, and article of manufacture for optimizing database queries using an automatic summary table. A query is analyzed using matching and compensation tests between the query at least one correlated subquery within the query and the automatic summary table to determine whether expressions occurring in the query, but not in the automatic summary table, can be derived using the automatic summary table. If so, the query is rewritten so that the automatic summary table is used.

Abstract: A method and system for use in a computing environment for selecting a subset of records from a set of records for placement of the subset of records in a plurality of destinations. A group of replica records is formed for a record of the subset of records, and a destination identification is assigned to each replica record, except one, of the group of replica records. A replica record associated with one of the plurality of destinations can be selected and can be placed in the associated destination.

Abstract: A method, apparatus, and article of manufacture for optimizing database queries using a derived summary table, wherein a definition of the summary table is based on a full select statement, including, but not limited to, a derived table involving nested GROUP BY operations and complex HAVING clauses with subqueries or joins, that is materialized in the table and describes how the summary table was derived. A query is analyzed using matching/compensation tests between the query and the definition of the summary table (that is, a query by itself) to determine whether expressions occurring anywhere in the query, but not in the summary table, can be derived using either the content in the summary table alone, or after combining (through some relational operator) the content of the summary table with other base tables, and hence the query is subsumed by or overlaps with the summary table definition.

Abstract: A method and system for graphically representing a plan for a query in a relational database management system is disclosed. The method includes receiving and processing an input query to form a plurality of plans, selecting at least one plan of the plurality of plans, and transforming the selected plan into a self-describing formatted file which is platform independent. The method further includes generating a graph representing the selected plan from the self-describing formatted file.

Abstract: A method and system for use in a computing environment for selecting a subset of records from a set of records for placement of the subset of records in a plurality of destinations. A group of replica records is formed for a record of the subset of records, and a destination identification is assigned to each replica record, except one, of the group of replica records. A replica record associated with one of the plurality of destinations can be selected and can be placed in the associated destination.

Abstract: A method and system for graphically representing a plan for a query in a relational database management system is disclosed. The method includes receiving and processing an input query to form a plurality of plans, selecting at least one plan of the plurality of plans, and transforming the selected plan into a self-describing formatted file which is platform independent. The method further includes generating a graph representing the selected plan from the self-describing formatted file.

Abstract: A method, apparatus, and article of manufacture for optimizing database queries using an automatic summary table. A query is analyzed using matching and compensation tests between the query at least one correlated subquery within the query and the automatic summary table to determine whether expressions occurring in the query, but not in the automatic summary table, can be derived using the automatic summary table. If so, the query is rewritten so that the automatic summary table is used.

Abstract: A method, apparatus, and article of manufacture for optimizing database queries using subsumption tests between the query and at least one summary table that comprises a cube index to determine whether an expression in the query can be subsumed in the summary table. The summary table stores at least one materialized view involving at least one GROUP BY operation that computes at least one of the following: (1) a cube, (2) a rollup, (3) a grouping set, and (4) a concatenation of cubes, rollups, grouping sets, and one or more grouping items. When the expression in the query can be subsumed in the summary table, the query is rewritten to use the summary table.

Abstract: A method, apparatus, and article of manufacture for optimizing database queries uses a derived summary table, wherein a definition of the summary table is based on a full select statement that is materialized in the table and describes how the summary table was derived. The summary table definition can be a complex query involving nested GROUP BY operations as well as complex HAVING clauses with subqueries or join operations. A query is analyzed using subsumption tests between the query and the definition of the summary table to determine whether expressions occurring anywhere in the query, but not in the summary table, can be subsumed in the summary table. In performing the query, an expression in the query is subsumed in the summary table when the expression can be re-derived from one or more of the columns of the summary table.

Abstract: A method for typed view hierarchies for an object-relational database management (OPDBMS). The views in the hierarchy are merged into a unified hierarchy view through case expressions for mapping and wrapping of overloaded columns. During the merge, the underlying logical tables are eliminated which results in a simplified query graph. The transformation is a non-loss operation which condenses the type information within the case expressions. This allows update, delete and insert operations to be resolved on the query graph on a local level. Using query rewrite rules, the case expressions may be simplified further.

Abstract: A method, apparatus, and article of manufacture for optimizing database queries using a materialized view for a table referenced in the query, wherein the materialized view has different properties than the referenced table. The materialized view may be replicated across multiple processors of the computer system, so that some or all of the query can be executed in a local fashion wherein there is no data movement required to perform the operations. The materialized view also may be partitioned across multiple processors of the computer system using a different partitioning key than the referenced table. The materialized view may be a vertical and/or horizontal subset of the table, so that only selected columns and/or tuples from the table are present therein. Columns may be added to the materialized view to contain pre-computed results of complex expressions, and indices may be created on the columns of the materialized view.

Abstract: An automated methodology, and an apparatus for practicing the methodology, which enables the power and flexibility inherent in shared nothing parallel database systems (MPP) to be utilized on complex queries which have, heretofore, contained query elements requiring local computation or local coordination of data computation performed across the nodes of the distributed system. The present invention provides these features and advantages by identifying and marking the subgraphs containing these types of query elements as "no TQ zones" in the preparation phase prior to optimization. When the optimizer sees the markings, it builds a plan that will force the computation of the marked subgraphs to be in the same section. This preparation phase also provides the partitioning information for all inputs to the "no TQ zones". This allows the bottom-up optimizer to correctly plan the partitioning for the "no TQ zones".

Abstract: Method and apparatus for detecting and stacking grouping sets to support GROUP BY operations with GROUPING SETS, ROLLUP and CUBE extensions in relational database management systems, with greatly reduced numbers of grouping sets. A first GROUP BY (element-list1) is input to a second GROUP BY (element-list2), resulting in the GROUP BY of the intersection of the two lists. This intersection property is then useable to reduce the number of GROUP BYs required to implement the grouping by GROUPING SETS, ROLLUPs, and CUBEs required for the online analytical processing of data contained in the database.

Abstract: An automated system for detecting and preventing mutating table violations of database integrity in a SQL query before generation and selection of an optimal query execution plan (QEP). This system modifies the query graph model (QGM) to restrict the choice of execution plans to those that avoid mutating table integrity (MTI) violations, thereby forcing database integrity during table mutation when executing the optimal QEP. Mutating table integrity violations are detected by evaluating the position in the QGM of each write-node referencing a particular base table with respect to each of the positions of all other read- and write-nodes referencing of the same base table. Every common-referencing node pair is tested for sequencing conflicts and a data-flow dam is inserted in the QGM where necessary or a poke query is inserted between the nodes to force the completion of the execution of one node before initiating execution of the other common-referencing node.