SIGMOD '86 Proceedings of the 1986 ACM SIGMOD international conference on Management of data
Practical selectivity estimation through adaptive sampling
SIGMOD '90 Proceedings of the 1990 ACM SIGMOD international conference on Management of data
Managing persistent objects in a multi-level store
SIGMOD '91 Proceedings of the 1991 ACM SIGMOD international conference on Management of data
Predicate migration: optimizing queries with expensive predicates
SIGMOD '93 Proceedings of the 1993 ACM SIGMOD international conference on Management of data
Optimization of dynamic query evaluation plans
SIGMOD '94 Proceedings of the 1994 ACM SIGMOD international conference on Management of data
Extensibility safety and performance in the SPIN operating system
SOSP '95 Proceedings of the fifteenth ACM symposium on Operating systems principles
Query execution techniques for caching expensive methods
SIGMOD '96 Proceedings of the 1996 ACM SIGMOD international conference on Management of data
Dealing with disaster: surviving misbehaved kernel extensions
OSDI '96 Proceedings of the second USENIX symposium on Operating systems design and implementation
Optimization and execution techniques for queries with expensive methods
Optimization and execution techniques for queries with expensive methods
Secure and portable database extensibility
SIGMOD '98 Proceedings of the 1998 ACM SIGMOD international conference on Management of data
JRes: a resource accounting interface for Java
Proceedings of the 13th ACM SIGPLAN conference on Object-oriented programming, systems, languages, and applications
Optimization of Queries with User-defined Predicates
VLDB '96 Proceedings of the 22th International Conference on Very Large Data Bases
Relational Query Optimization with Enhanced ADTs
Relational Query Optimization with Enhanced ADTs
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While object-relational database servers can be extended with user-defined functions (UDFs), the security of the server may be compromised by these extensions. The use of Java to implement the UDFs is promising because it addresses some security concerns. However, it still permits interference between different users through the uncontrolled consumption of resources. In this paper, we explore the use of a Java resource management mechanism (JRes) to monitor resource consumption and enforce usage constraints. JRes enhances the security of the database server in the presence of extensions allowing for (i) detection and neutralization of denial-of-service attacks aimed at resource monopolization, (ii) monitoring resource consumption which enables precise billing of users relying on UDFs, and (iii) obtaining feedback that can be used for adaptive query optimization. The feedback can be utilized either by the UDFs themselves or by the database system to dynamically modify the query execution plan. Both models have been prototyped in the Cornell Predator database system. We describe the implementation techniques, and present experiments that demonstrate the effects of the adaptive behavior facilitated by JRes. We conclude that, minimally, a database system supporting extensions should have a built-in resource monitoring and controlling mechanism. Moreover, in order to fully exploit information provided by the resource control mechanisms, both the query optimizer and the UDFs themselves should have access to this information.