Abstract: A database system includes database software to receive a query specifying a join of plural base tables, and to determine whether a foreign key and primary key relationship exists between join columns specified by the query and a materialized view definition. Based on the existence of the foreign key and the primary key relationship between join columns specified by the query and the materialized view definition, the database software determines that a result for the received query is to be computed from the materialized view.

Abstract: A database system is capable of processing a query and providing a progress indicator of the processing of the query based on at least a first cost factor. Initially, an estimate is set for the first cost factor. During processing of the query, the estimate of the first cost factor is updated to enable refinement of the progress indicator.

Abstract: A method or apparatus for use with a database system that stores a join view associated with plural base relations includes receiving modification operations to modify at least two of the base relations of the join view, and re-ordering the received modification operations to avoid concurrent execution of modification operations of more than one of at least two base relations.

Abstract: A database system includes a storage to store a view containing results of a cube-based operation on at least one base table, with the view containing a first result set for a group-by on a first grouping set, and a second result set for a group-by on a second grouping set. In response to a change to the at least one base table, a controller updates the first result set by computing a change to the first result set based on a change in the at least one base table, and updates the second result set by computing a change to the second result set based on the change to the first result set.

Abstract: A method and apparatus identifies SQL statements in a first transaction that specify modification operations that are commutative and associative. The SQL statements are combined into one SQL statement, and the one SQL statement is submitted to a database system. Optionally, or alternatively, multiple transactions can be grouped together into one transaction.

Abstract: Auxiliary relations are used to maintain a materialized view. The materialized view comprises results of some operation performed between two or more base relations of a parallel database management system comprising a plurality of nodes. The two or more base relations are distributed to the nodes according to some partitioning strategy. Each auxiliary relation is partitioned according to the join attribute in the materialized view definition. During join or other operations involving the relations, the auxiliary relations, not the base relations, are used to construct join results and to maintain the materialized view.

Abstract: A database system includes a rescheduler that performs rescheduling of transactions in a scheduling queue based on one or more criteria. One criterion is whether a first transaction in the queue can be performed as a synchronized scan of a table with a second transaction that is currently executing. This enables the first and second transactions to share a segment of a buffer storage pool.

Abstract: A database system receives a transaction that causes a tuple to be integrated into a join view. In response to receiving the transaction, a predefined first lock is placed on at least a portion of the join view, the predefined first lock conflicting with either a shared lock or an exclusive lock placed on the join view, but not conflicting with another predefined first lock placed on the join view. Also, a latch or semaphore associated with a value of a predetermined attribute of the tuple is obtained before integrating the tuple into the join view.

Abstract: A database system includes a locking mechanism for an aggregate materialized view defined on base relations. In response to updates of a base relation, predefined locks are placed on the aggregate materialized view. With locking mechanisms, transaction concurrency is enhanced by enabling concurrent updates of the materialized view by plural transactions in certain cases, while avoiding the situation in which multiple tuples belonging to the same group are integrated as separate tuples into the aggregate materialized view.

Abstract: A database system includes a locking mechanism for a view defined on one or more base relations. A B-tree index is defined on the view. In response to updates of a base relation, predefined locks are placed on the view. With locking mechanisms according to some embodiments of the invention, concurrency of transactions that access the view and B-tree index is enhanced by enabling concurrent updates of the materialized view by plural transactions in certain cases, while avoiding read-write and write-read conflicts.

Abstract: A database system includes a locking mechanism for a materialized view defined on base relations. In response to updates of a base relation, a name lock is placed on the materialized view. The name lock is a type of exclusive lock and is associated with a data structure containing a first parameter to identify a base relation of the materialized view being updated, and a second parameter to indicate a number of transactions updating the base relation. With locking mechanisms according to some embodiments of the invention, transaction concurrency is enhanced by enabling concurrent updates of a materialized view by plural transactions in certain cases.

Abstract: A database system includes a locking mechanism for a materialized view defined on base relations. In response to updates of a base relation, a predefined lock (e.g., Y lock or IY lock) is placed on the materialized view. With the locking mechanism, transaction concurrency is enhanced by enabling concurrent updates of a materialized view by plural transactions in certain cases.

Abstract: Auxiliary relations are used to maintain a materialized view. The materialized view comprises results of some operation performed between two or more base relations of a parallel database management system comprising a plurality of nodes. The two or more base relations are distributed to the nodes according to some partitioning strategy. Each auxiliary relation is partitioned according to the join attribute in the materialized view definition. During join or other operations involving the relations, the auxiliary relations, not the base relations, are used to construct join results and to maintain the materialized view.

Abstract: A parallel hash ripple join algorithm partitions tuples of two relations for localized processing. The algorithm is non-blocking and may be performed in a parallel, multi-processor environment. At each processing node, the tuples are further partitioned such that join operations may be performed as tuples are redistributed to each node during the partitioning.

Abstract: A database system includes a transaction rescheduling mechanism that reorders pending transactions based on whether one or more of the pending transactions conflict with any transactions that have been scheduled for execution. In one arrangement, the received pending transactions are stored in a first queue. The transactions that are scheduled for execution are stored in a second queue. The transactions are moved from the first queue to the second queue based on the reordering by the transaction rescheduling mechanism.

Abstract: A method and apparatus determines (1) if a materialized view can be used to respond to a query for data stored in one or more base tables of a database system; and/or (2) if the materialized view needs to be updated in response to an update query. A query expression tree represents the query, and a materialized view expression tree represents the materialized view. The components of the query expression tree are compared with components of the materialized view expression tree to determine if the materialized view covers the query that is, the tuples in the result of the query expression are a subset of the tuples in the result of the materialized view expression.

Abstract: A non-blocking parallel band join method and apparatus partitions tuples of two relations for localized processing. At each processing node, the tuples are further partitioned such that join operations may be performed efficiently, as tuples are received by the node during the partitioning.

Abstract: A parallel spatial join index is used for efficient join operations involving spatial data, including polygon data. The join operations between spatial data from two different tables are performed in parallel in a multi-processor environment. Join indices are created, based upon spatial object attributes from the two tables. Auxiliary relations are constructed from the two tables as well, and further include data for avoiding duplicate join results. R-trees index the auxiliary relations and B-trees index the join indices.

Abstract: A non-blocking parallel spatial join algorithm generates the spatial join result tuples continuously even in the event of memory overflow. The algorithm employs duplicate avoidance techniques to avoid the blocking and time-consuming removal of duplicates. The algorithm also uses parallelism to improve performance.