The decreasing cost of computing makes it economically viable to reduce the response time of decision support queries by using parallel execution to exploit inexpensive resources. This goal poses the following query optimization problem: Minimize ...

In this paper, we study the scheduling and optimization problems of parallel query processing using interoperation parallelism in a shared-memory environment and propose our solutions for XPRS. We first study the scheduling problem of a set of a ...

During the past decade, parallel database systems have gained increased popularity due to their high performance, scalability and availability characteristics. With the predicted future database sizes and the complexity of queries, the scalability of ...

This paper describes the Query Rewrite facility of the Starburst extensible database system, a novel phase of query optimization. We present a suite of rewrite rules used in Starburst to transform queries into equivalent queries for faster execution, ...

This paper describes testing of rule conditions and execution of rule actions in Ariel active DBMS. The Ariel rule system is tightly coupled with query and update processing. Ariel rules can have conditions based on a mix of patterns, events, and ...

Static analysis methods are given for determining whether arbitrary sets of database production rules are (1) guaranteed to terminate; (2) guaranteed to produce a unique final database state; (3) guaranteed to produce a unique stream of observable ...

In this paper we introduce DOODLE, a new visual and declarative language for object-oriented databases. The main principle behind the language is that it is possible to display and query the database with arbitrary pictures. We allow the user to tailor ...

The concept of a trigger is central to any active database. Upon the occurrence of a trigger event, the trigger is “fired”, i.e, the trigger action is executed. We describe a model and a language for specifying basic and composite trigger events in the ...

Database programming languages like O₂, E, and O++ include the ability to iterate through a set. Nested iterators can be used to express joins. This paper describes compile-time optimizations similar to relational transformations like join reordering ...

In this paper, we propose locking protocols that are useful for real-time databases. Our approach is motivated from two main observations. First, locking protocols are widely accepted and used in most database systems. Second, in real-time databases it ...

Buffer coherency control can be achieved through retaining a lock (shared, exclusive, etc.) on each page in the buffer, even after the requesting transaction has committed. Depending upon the lock mode held for retention and the compatibility of lock ...

We present efficient and flexible methods which permit read-only transactions that do not mind reading a possibly slightly old, but still consistent, version of the data base to execute without acquiring locks. This approach avoids the undesirable ...

The support of the superclass-subclass concept in object-oriented databases (OODB) makes an instance of a subclass also an instance of its superclass. As a result, the access scope of a query against a class in general includes the access scope of all ...

We investigate the performance of some of the best-known object clustering algorithms on four different workloads based upon the tektronix benchmark. For all four workloads, stochastic clustering gave the best performance for a variety of performance ...

Scans through large collections of complex objects often cannot be avoided. Even if sohphisticated indexing mechanisms are provided, it may be necessary to evaluate simple predicates against data stored on disk for filtering. For traditional record ...

Oracle first implemented multiversioning, which was called read consistency, in Version 4 (ea. 1983) of the kernel. It supported the old master/new master programming paradigm for both application builders and query-processor implementors while avoiding ...