Hewlett-packard Development Company, L.P.

Compaq Computer Corporation, Inc.

Tandem Computers Incorporated

Anoop Sharma

Hansjorg Zeller

Michael James Hanlon

Johannes Klein

Robbert C Van Der Linden

Robert Matthew Wehrmeister

David W Birdsall

Viral Shah

Brian Shaun Vickery

Gary Martin Gilbert

Raj K Rathee

Subbarao Kakarlamudi

Vinita Subramanian

Venkatesan N Ranganathan

Lars B Plum

Sudhir Radhakrishna Shetiya

Andrew D Therber

Selvaganesan Govindarajan

Thomas Canivel Reyes

A system and method for providing parallel result streams for database queries is provided. The system includes a network including a client, a server, and a database. The client executes an application and sends a query to the server. In response, the server compiles the query to produce a query plan, executes statements in the query plan and sends parallel result streams to the client.

Providing parallel result streams for database queries

There is provided a computer-executed method of freeing memory. One exemplary method comprises receiving a message from a user process. The message may specify a virtual address for a memory segment. The virtual address may be mapped to the memory segment. The memory segment may comprise a physical page. The method may further comprise identifying the physical page based on the virtual address. Additionally, the method may comprise freeing the physical page without unmapping the memory segment.

System and method for freeing memory

There is provided a computer-implemented method of modifying a query executing in a database management system. The method comprises sending a no-wait message for the query to a control broker. The method also comprises receiving a reply to the no-wait message from the control broker. The reply to the no-wait message specifies a modification to the query. Additionally, the method comprises performing the modification.

System and method for modifying an executing query

An automated method to align column values to proper byte boundaries for rapid scanning in a parallel processing database system. A table definition is received having a logical order of fields. The fields are re-ordered to create a physical order of fields. The physical order of fields has fixed length fields having a same byte alignment requirement positioned adjacent to each other in descending order from largest size to smallest size, and wherein a first fixed length field in the physical order is aligned on a proper byte boundary. Other embodiments, aspects and features are also disclosed.

Automated re-ordering of columns for alignment trap reduction

Systems and methods to indicate whether to store a database query language module in a local directory or a global directory are disclosed. An application program can be created once, tested once, and deployed in separate environments. The database query language modules can be shared among a group of application programs running in a common environment. Separate query language modules can be maintained for each environment.

Systems and methods for handling multiple static query modules for distinct environments

A database management system includes an execution engine that, upon rollback of an aborted transaction, has the ability to set fields of the rows that are updated or deleted by the transaction prior to aborting. In particular, when a select, update or delete statement includes a &ldquo;set on rollback&rdquo; clause, the respective table access operator of the execution engine modifies the &ldquo;before image&rdquo; of each row that is stored by the transaction log manager. The modified before image includes the field updates specified by the set on rollback clause. If a transaction associated with the statement aborts, when the transaction log manager restores the before images of each row that was deleted or updated by the transaction, the restored before images include the field updates specified by the set on rollback clause.

Database management system and method for updating specified tuple fields upon transaction rollback

A structured query language (SQL) grouping and aggregation system and method that incorporates hash-based techniques, several overflow handling strategies and statistics-based process-selection criteria. The method can execute SQL group-by queries on distributed database tables or tables stored locally to the database management system (DBMS) processor executing the grouping method. Hash-based techniques allow groupings and aggregates to be generated on the fly through the use of partial aggregates maintained in primary memory. Where primary memory is limited, groups and aggregates are still generated for as many groups as can be maintained in primary memory, while various overflow procedures are provided for buffering ungrouped data and writing that data to an overflow disk file for later processing. In one overflow procedure, raw data from groups that cannot be aggregated in primary memory are buffered then written to the overflow disk file. In a second overflow procedure, ungroupable raw data is formatted the same as data being aggregated in the group table, buffered, and then written to the overflow file. In a third overflow procedure, ungroupable raw data is partially aggregated in an output buffer maintained in primary memory before being written to the overflow file maintained in secondary memory. Database table statistics maintained by a cataloger are consulted to determine whether hash-based grouping or conventional sort based grouping should be used to execute a group-by query. The system is adaptable to running a grouping query against a partitioned database on distributed processors.

Hash-based database grouping system and method

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San Jose, CA, United States of America

Anoop Sharma