Abstract: Techniques are disclosed for accessing a dimensional data model when processing a query. In one embodiment, the query is processed by performing a two-stage zigzag join operation including a zigzag main join and a zigzag back join. The zigzag main join is configured to generate a set of row identifiers of fact records satisfying any local predicates in the query. The zigzag back join is configured to generate query results based on the set of row identifiers. The query results are returned responsive to the query.

Abstract: There is disclosed a system and method for executing multiple distinct aggregate queries. In an embodiment, the method comprises: providing at least one Counting Bloom Filter for each distinct column of an input data stream; reviewing count values in the at least one Counting Bloom Filter for the existence of duplicates in each distinct column; and if necessary, using a distinct hash operator to remove duplicates from each distinct column of the input data stream, thereby removing the need for replicating the input data stream and minimizing distinct hash operator processing. Also, the use of Counting Bloom Filters for monitoring data streams allow an early duplicate removal of the input stream of data, resulting in savings in computation time and memory resources.

Abstract: There is disclosed a system and method for executing multiple distinct aggregate queries. In an embodiment, the method comprises: providing at least one Counting Bloom Filter for each distinct column of an input data stream; reviewing count values in the at least one Counting Bloom Filter for the existence of duplicates in each distinct column; and if necessary, using a distinct hash operator to remove duplicates from each distinct column of the input data stream, thereby removing the need for replicating the input data stream and minimizing distinct hash operator processing. Also, the use of Counting Bloom Filters for monitoring data streams allow an early duplicate removal of the input stream of data, resulting in savings in computation time and memory resources.

Abstract: Disclosed is a data processing system implemented method, a data processing system and an article of manufacture for executing a query having a union operator. A data processing system implemented method direct the data processing system to execute a query against a database having data objects. The query has sub-queries and having a union operator. The union operator is operable on sub-queries associated with the query. The database is operatively coupled to the data processing system.

Abstract: Disclosed is a data processing system, a data processing system implemented method and an article of manufacture for executing a query having a union all operator. The data processing system implemented method directs the data processing system to execute a query against a data object. The query has a union all operator and has a set of data modifying operators. The set of data modifying operators is associated with the union all operator. The union all operator references the data object. The data processing system implemented method includes preventing the union all operator from being applied to the data object, and applying the set of data modifying operators against the data object.

Abstract: A query processing system has a query processor and a data manager. The query processor calls the data manager to carry out data access for a query including a filtering operation. The data manager accesses the data in a set of data and before returning the data, initiates a callback to the query processor to determine if the located data meets the filtering criteria. Where the data does not satisfy the filtering criteria, the data manager seeks additional data in the set of data, without having to return the first located data to the query processor.

Abstract: Disclosed is a data processing system implemented method, a data processing system and an article of manufacture for executing a query having a union operator. The data processing system implemented method directs the data processing system to process a query against data objects. The data objects are operatively coupled to the data processing system. The query includes a parent operator. The parent operator references a union operator. The union operator references sub-queries. The sub-queries reference the data objects. The data processing system implemented method includes noting a set of partitionings for the union operator, the noted set of partitionings being based on the sub-queries and being based on the data objects reference by the sub-queries, and executing the query having the union operator, the execution of the query being based on the noted set of partitionings and the parent operator.

Abstract: A query processing system having a data manager, and a query manager also includes a buffer. The query manager calls the data manager to access data based on a query. Where there is no predicate check or consumption operation on the record accessed, the data manager will notionally return the record to the query manager. However, the data manager accomplishes the return by writing the relevant portions of the record to a buffer. The data manager maintains stabilization of the page containing the record while the buffer is being written to. The data manager continues to access records on the stabilized page and to write such records to the buffer where appropriate. The query manager retrieves the records from the buffer after the data manager has completed its operation resulting from the query manager call.

Abstract: The present invention provides a system and a method for materializing records in a result set in response to a query. The computer system comprises a server and a client. The server has a database and a database management system for providing access to the database. The client is operatively coupled to the database management system. The client is adapted to provide a query to the database management system and the database management system is adapted to materialize a number of records in a result set in response to the query. The number of materialized records is selected to reduce inefficient materialization of records from the database in response to the query.

Abstract: A procedure optimizes command execution in a database system. According to one embodiment, the database system stores data records on data pages, and provides an identifier for each data page. The identifier indicates when any of the data records contained in the data page were last modified. A data record is selected from a data page and copied to a second storage area. Verification that the selected data record has not been modified since the time that is was copied to the second storage area is based upon the identifier, and then the command is executed.

Abstract: A query processing system has a query processor and a data manager. The query processor calls the data manager to carry out data access for a query including a filtering operation. The data manager accesses the data in a set of data and before returning the data, initiates a callback to the query processor to determine if the located data meets the filtering criteria. Where the data does not satisfy the filtering criteria, the data manager seeks additional data in the set of data, without having to return the first located data to the query processor.

Abstract: A method for ordering a first and a second character string is disclosed. The method comprises determining which of the two character strings has a lower collating weight according to a first dictionary sort order table with a non-unique collating sequence, and determining which of the two character strings has a lower collating weight according to a second dictionary sort order table with a unique collating sequence.

Abstract: The present invention provides a system and a method for materializing records in a result set in response to a query. The computer system comprises a server and a client. The server has a database and a database management system for providing access to the database. The client is operatively coupled to the database management system. The client is adapted to provide a query to the database management system and the database management system is adapted to materialize a number of records in a result set in response to the query. The number of materialized records is selected to reduce inefficient materialization of records from the database in response to the query.

Abstract: A system, method and computer readable medium containing programming instructions for optimizing command execution in a database system is disclosed. According to one embodiment of the present invention, the database system stores data records on data pages, and provides a log sequence number for each data page. The log sequence number indicates when any of the data records contained in the data page were last modified. A data record is selected from a data page and copied to a second storage area. The present invention verifies that the selected data record has not been modified since the time that is was copied to the second storage area based upon the log sequence number, and then executes the command.

Abstract: A query processing system having a data manager, and a query manager also includes a buffer. The query manager calls the data manager to access data based on a query. Where there is no predicate check or consumption operation on the record accessed, the data manager will notionally return the record to the query manager. However, the data manager accomplishes the return by writing the relevant portions of the record to a buffer. The data manager maintains stabilization of the page containing the record while the buffer is being written to. The data manager continues to access records on the stabilized page and to write such records to the buffer where appropriate. The query manager retrieves the records from the buffer after the data manager has completed its operation resulting from the query manager call.

Abstract: A query processing system has a query processor and a data manager. The query processor calls the data manager to carry out data access for a query including a filtering operation. The data manager accesses the data in a set of data and before returning the data, initiates a callback to the query processor to determine if the located data meets the filtering criteria. Where the data does not satisfy the filtering criteria, the data manager seeks additional data in the set of data, without having to return the first located data to the query processor.