International Business Machines Corporation

Lucent Technologies Inc.

Red Brick Systems, Inc.

Latha S Colby

David G Wilhite, Jr

William McKenna

Richard Lee Cole

Galt Johnson

Nasi Jazayeri

Edward P Haslam

Jun Rao

Sangeeta T Doraiswamy

Quanzhong Li

Hetal Thakkar

Lee E Schumacher

David G Wilhite

Guy Maring Lohman

Mir Hamid Pirahesh

Eugene Jon Shekita

Kevin Scott Beyer

Fatma Ozcan

Kenneth Andrew Ross

Volker Gerhard Markl

Daniel Francis Lieuwen

Minglong Shao

Craig J Bunger

Akira Kawaguchi

Zografoula Vagena

Gopal B Mulagund

William J McKenna

William Mckenna

William J Mckenna

According to one embodiment of the present invention, a method for processing join predicates in full-text indexes is provided. The method includes evaluating local predicates of an outer full text index to generate a first posting list of documents. For each document in the first posting list, the value of a join attribute is determined and an inner full text index is probed to obtain a second posting list of documents containing one of the join attributes determined for each document. Local predicates of an inner full text index are evaluated to generate a third posting list of documents, and the second posting list is merged with the third posting list to generate a merge list of documents. Documents in the first posting list may be paired up with documents in the merge list.

Join algorithms over full text indexes

A method and system for cleansing anomalies from sequence-based data at query time. Sequence-based data such as RFID data is loaded into a database. One or more cleansing rules are received at a cleansing rules engine. The cleansing rule engine converts the cleansing rule(s) to a template that includes logic to compensate for anomalies in the sequence-based data. A query to retrieve the sequence-based data is received by a query rewrite engine. The query rewrite engine rewrites the query by applying the template logic. The rewritten query is executed at query time. The result of the rewritten query execution is identical to the result of executing the original query on a data set generated by applying the cleansing rule to all of the sequence-based data.

Method and system for cleansing sequence-based data at query time

A method is disclosed for executing a predetermined query plan, the method comprising: executing a portion of the query plan; providing a reordered query plan; comparing ranking metrics for the query plans; and executing the query plan having the lower ranking metric.

Adaptively reordering joins during query execution

A method for cleansing anomalies from sequence-based data at query time. Sequence-based data such as RFID data is loaded into a database. A cleansing rule is received at a cleansing rules engine. The cleansing rule engine converts the cleansing rule to a template that includes logic to compensate for anomalies in the sequence-based data. A query to retrieve the sequence-based data is received by a query rewrite engine. The query rewrite engine rewrites the query by applying the template logic and an expanded rewrite technique. The rewritten query is executed at query time. The result of the rewritten query execution is identical to the result of executing the original query on a data set generated by applying the cleansing rule to all of the sequence-based data.

Method for cleansing sequence-based data at query time

Technique are provided for maintaining pre-computed aggregate views. A pre-computed aggregate view derived from one or more base tables is received, the pre-computed aggregate view including a pre-computed aggregate table and a view definition, the view definition including aggregate functions that can be any combination of sum, sum distinct, count(*), count, count distinct, min, and max, the view definition further including expressions that may be nullable. Changes to the one or more base tables are received, the changes being represented as insertions and deletions and being non-minimal. A set of incremental modifications to the pre-computed aggregate table are derived and applied based on the changes to the one or more base tables, wherein modifications may include any combination of inserts, deletes, and updates. Deriving the set of incremental modifications to the pre-computed aggregate table includes deriving a first table wherein each record, representing an aggregated group of changes, shows for each aggregation function, the contributions of base table changes that are insertions for the group and the contributions of base table changes that are deletions for the group and using some combination of information in the first table, the pre-computed aggregate table, and the one or more base tables from which the pre-computed view is derived.

Maintaining pre-computed aggregate views incrementally in the presence of non-minimal changes

Methods and apparatus implementing a technique for incrementally maintaining pre-computed aggregate views. In general, the technique includes: receiving a pre-computed aggregate view derived from one or more base tables. The pre-computed aggregate view including a pre-computed aggregate table and a view definition. The view definition including aggregation functions that can be any combination of sum, sum distinct, count(*), count distinct, min, and max. The view definition further including expressions that may be nullable. The technique includes receiving changes to the base table, the changes being non-minimal. The technique includes analyzing the view definition, including the type of aggregation functions and the nullability and data type of columns and expressions in the view definition, to reduce or eliminate the use of information in base tables in order to define the incremental modifications to the pre-computed aggregate table.

A system and method for answering a relational database query is presented. According to an embodiment of the present invention, a database query is received. It is then determined whether that query can be rewritten in such a manner as to be able to utilize a precomputed view, such that an answer to the rewritten query is equivalent to an answer to the original query. If the query can be rewritten, it is determined whether the rewritten query can more efficiently derive the answer than the original query. The query which has the most efficiently derived answer is the query which is utilized to derive that answer.

System and method for rewriting relational database queries

Server-integrated methods and apparatus for processing precomputed views for answering user queries on a database are described. In accordance with one embodiment, a system for answering user queries on a database stored on a server includes a query processing system integrated into the server and configured to respond to user queries, and a query processing system integrated into the server and configured to process precomputed results of user queries on the database. In another aspect, a method of answering user queries on a database stored on a server includes responding to user queries received at the server, and processing, at the server, precomputed results of user queries on the database.

Server integrated system and methods for processing precomputed views

Methods and apparatus for processing precomputed views for answering user queries on a database are described. In accordance with one aspect, a user database query on precomputation strategy effectiveness is responded to by defining, based upon user database query history, an analysis space consisting of a subset of all possible views for the database, and by characterizing the views in the analysis space. In accordance with a second aspect, a structure is imposed on an analysis space consisting of a subset of all possible views for the database based upon the capabilities of a query rewriting facility, and the views in the analysis space are characterized. In accordance with a third aspect, an analysis space consisting of a subset of all possible views for the database is defined, and a cost formula is applied to the analysis space based upon a user-defined subset of the data contained in the database. In accordance with a fourth aspect, an analysis space that includes a candidate view composed of a combination of two or more constituent views is defined, and the views in the analysis space are characterized.

Defining and characterizing an analysis space for precomputed views

The invention features methods and apparatus for processing precomputed views for answering user queries on a database. In accordance with one aspect, a user query on the database is analyzed, and a candidate view based upon the user query is generated.

System and method for determining and generating candidate views for a database

A system and a method maintain a precomputed view corresponding to detail data in a database server by: determining a maintenance plan to refresh the precomputed view when detail data is changed; integrating the maintenance plan with a query execution plan in the database server; and executing the query execution plan.

System for maintaining precomputed views

In a database, a database manager can generate a view, which can be considered as a subset of the database, and which is placed outside the database for use without disturbing the database. However, if the database changes, the views will not reflect those changes, because the views are separate from the database. To solve this problem, a process called &ldquo;refreshing&rdquo; keeps the views consistent with the data within the database. But different refreshing approaches are used: some views require immediate refreshing when the database changes, other types can be refreshed at later times, and still other types can be refreshed at different times and intervals. The invention presents a system which keeps data consistent among the views and the database, despite the different times of refreshing undertaken.

Growing community of inventors

Los Altos, CA, United States of America

Latha S Colby