International Business Machines Corporation

Wenbin Ma

Calisto Paul Zuzarte

Qi Cheng

Nattavut Sutyanyong

Abhinav Goyal

Liping Zhang

Mir Hamid Pirahesh

Vincent Kulandaisamy

Linqi Liu

Jian Le

Joshua D Gross

Embodiments described herein provide a solution for optimizing a generating of query search results. A filtering search term (e.g., a search term that is used in a query to perform filtering aggregations of the query search results) is identified. A filtering bitmap that has a plurality of mapped locations corresponding to data values for the filtering search term is created. As a data value in the filtering search term is encountered during a scan of the query search results, the corresponding mapped location is updated. Each mapped location in the filtering bitmap is read to determine whether the value corresponding to the mapped location satisfies the filtering aggregation. The filtering aggregation can then be performed (e.g., prior to any grouping aggregation) by removing any of the query search results determined, based on the filtering bitmap, as having data values for which the filtering aggregation is not satisfied.

Grouping aggregation with filtering aggregation query processing

Provided herein are techniques for processing a database query aggregating data. Data tuples of a database object each including a grouping element and a data element are analyzed to determine a length of the data element for each data tuple. A plurality of tables each accommodate a successively greater length for the data element. A corresponding table of the plurality of tables to store each data tuple is determined based on the length of the data element of that data tuple relative to the accommodated lengths of the plurality of tables. Each data tuple in the determined corresponding table is stored to group the data tuples within each of the plurality of tables based on the grouping element, and an indication of corresponding tables containing members for each group is provided. The groups are combined across the plurality of tables to aggregate the data tuples for a database query.

Efficient database query aggregation of variable length data

Responding to relational database queries (for example, SQL queries) in a new way. More specifically, qualifying queries are written (for example, written by a human individual) in a way so that a join operation precedes a row limiting operation. Notwithstanding the fact that the join operation precedes the row limiting operation, when responding to the query, machine logic (for example, software) performs the row limiting operation before the join operation. This can improve time and processing efficiency.

Optimizing relational database queries with multi-table predicate expressions

A method, system, and computer program product for optimizing database queries in a data processing system. A query optimization (QO) utility maximizes the query coverage of Materialized Query Tables (MQTs) in order to efficiently process various types of incoming queries to a database engine. In particular, the QO utility enables MQT technology for nullable foreign key columns in a number of table joins involving fact tables and dimension tables, in which the fact tables and dimension tables have column data which are not null. The QO utility also enables MQT query matching for a relational database engine for non-additive measures, and improves the performance of existing query-matching capabilities for a relational database engine for additive measures. The QO utility specifies a number of functionally dependent relationships between the columns of a table in order to enhance the query matching abilities of the database engine.

Database query optimization

A system for use with an information retrieval system, in which system is used for transforming a database statement containing a first subquery and a second subquery joined together, the first subquery including a group by operation over a child subquery, the information retrieval system comprising means for removing the first subquery from the database statement thereby eliminating the join between the first subquery and the second subquery.

System for aggregation subquery join elimination

A method for use with an information retrieval system, in which the method is used for transforming a database statement containing a first subquery and a second subquery joined together, the first subquery including a group by operation over a child subquery, the method comprising removing the first subquery from the database statement thereby removing the join between the first subquery and the second subquery.

Method for aggregation subquery join elimination

A system and method transform queries with subqueries, using window aggregation. An optimizer in a relational database management system transforms queries to optimize their efficiency and speed. The method transforms queries that have a subquery, replacing the subquery with a window aggregation function. In the case of a correlated subquery, the window aggregation function is partitioned by a correlated column of a correlated table. All data in the main select clause, or outer block, of the query that was obtained through references to the correlated table is instead obtained through the new window aggregation subquery. By using window aggregation, the aggregation is performed at the same time as the selection of relevant data from the correlated table, thereby compiling all needed data in a single pass through the table or view. Reducing the number of times that tables or views are accessed reduces the computational demands of a query.

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Vaughn, Canada

Wenbin Ma