The VLDB Endowment is a non-profit foundation whose objective is to promote scientific and educat... more The VLDB Endowment is a non-profit foundation whose objective is to promote scientific and educational activities in the area of large-scale data, information, and knowledge management. The Endowment serves as the steering committee for the VLDB conference series. The Endowment also sponsors various scholarly activities. It has established a program that supports summer schools, tutorials, and other training activities of this kind, in countries that could otherwise not afford the expenses for such events. The Endowment is ...
The HiPAC (High Performance ACtive database system) project addresses two critical problems in ti... more The HiPAC (High Performance ACtive database system) project addresses two critical problems in time-constrained data management: the handling of timing constraints in databases, and the avoidance of wasteful polling through the use of situation-action rules that are an integral part of the database and are monitored by the DBMS's condition monitor. A rich knowledge model provides the necessary primitives for definition of timing constraints, situation-action rules, and precipitating events. The execution model allows various coupling modes between transactions, situation evaluations and actions, and provides the framework for correct concurrent execution of transactions and triggered actions. Different approaches to scheduling of time-constrained tasks and transactions are explored and an architecture is being designed with special emphasis on the interaction of the time-constrained, active DBMS and the operating system. Performance models are developed to evaluate the various design alternatives.
In a recent paper, we proposed adding a STOP AFTER clause to SQL to permit the cardinality of a q... more In a recent paper, we proposed adding a STOP AFTER clause to SQL to permit the cardinality of a query result to be explicitly limited by query writers and query tools. We demonstrated the usefulness of having this clause, showed how to extend a traditional cost-based query optimizer to accommodate it, and demonstrated via DB2-based simulations that large performance gains are possible when STOP AFTER queries are explicitly supported by the database engine. In this paper, we present several new strategies for efficiently processing STOP AFTER queries. These strategies, based largely on the use of range partitioning techniques, offer significant additional savings for handling STOP AFTER queries that yield sizeable result sets. We describe classes of queries where such savings would indeed arise and present experimental measurements that show the benefits and tradeoffs associated with the new processing strategies.
... Vivek Maganty$ John Williamst ... Moreover, PEST0 generalizes existing no-tions of jiltenzd b... more ... Vivek Maganty$ John Williamst ... Moreover, PEST0 generalizes existing no-tions of jiltenzd browsing by allowing filters to be spec-ified (1) in place, on the browse structure, (2) on any level(s) of nested sets, and (3) with arbitrarily complex predicates (including explicit and ...
M. J. Carey, L. M. Haas, P. M. Schwarz, M. Arya, W. E Cody, R. Fagin, M. Flickner, A. W. Luniewsk... more M. J. Carey, L. M. Haas, P. M. Schwarz, M. Arya, W. E Cody, R. Fagin, M. Flickner, A. W. Luniewski, ... W. Niblack, D. Petkovic, J. Thomas, J. H. Williams and EL Wimmers ... IBM Almaden Research Center, San Jose, CA 95 120
IEEE Transactions on Knowledge and Data Engineering, 1990
... Manuscript received August I, 1989: revised December 4, 1989. LM Haas, GM Lohman. J. McPherso... more ... Manuscript received August I, 1989: revised December 4, 1989. LM Haas, GM Lohman. J. McPherson, PF Wilms, G. Lapis, B. Lindsay, and H. Pirahesh are with IBM Almaden Research Center. San Jose. CA 95120. W. Chang is with Oracle Corporation, Belmont, CA 94002. ...
Since its introduction, XML, the eXtended Markup Language, has quickly emerged as the universal f... more Since its introduction, XML, the eXtended Markup Language, has quickly emerged as the universal format for publishing and exchanging data in the World Wide Web. As a result, data sources, including object-relational databases, are now faced with a new class of users: clients and customers who would like to deal directly with XML data rather than being forced to deal with the data source's particular (e.g., object-relational) schema and query language. The goal of the XPERANTO project at the IBM Almaden Research Center is to serve as a middleware layer that supports the publishing of XML data to this class of users. XPERANTO provides a uniform, XML-based query interface over an object-relational database that allows users to query and (re)structure the contents of the database as XML data, ignoring the underlying SQL tables and query language. In this paper, we give an overview of the XPERANTO system prototype, explaining how it translates XML-based queries into SQL requests, receives and then structures the tabular query results, and finally returns XML documents to the system's users and applications.
Earlier studies have observed that in moderately-loaded real-time database systems. using an Earl... more Earlier studies have observed that in moderately-loaded real-time database systems. using an Earliest Deadline policy to schedule tasks results in the fewest missed deadlines. When the real-time system is overloa&d, however. an Earliest Deadline schedule perfoms worse than most other policies. This is due to are close to m i s s i i their deadliies. In this paper, we present a new piority assignment algorithm called Adaptive Earliest Deadlinc (AED), which features a feedback control mechanism that detects overload conditions and modifies transaction priaity assignments -1y.
Priority in DBMS Resource Scheduling Michael J. Carey Rajiv Jauhari MironLivny Computer Sciences ... more Priority in DBMS Resource Scheduling Michael J. Carey Rajiv Jauhari MironLivny Computer Sciences Department University of Wisconsin Madison, WI 53706 ABSTRACTIn this paper, we address the problem of priority scheduling in a database management system. ...
The eXtended Markup Language (XML) is quickly emerging as the universal format for publishing and... more The eXtended Markup Language (XML) is quickly emerging as the universal format for publishing and exchanging data on the World Wide Web. As a result, data sources, including object-relational databases, are now faced with a new class of users and applications; customers and programs that would like to deal directly with XML data rather than being forced to deal with the data source's particular (e.g., objectrelational) schema and query language. The goal of the XPERANTO middleware project is to support this new class of users and applications. XPERANTO does this by providing query-able "XML Views" over the underlying objectrelational database. Users can then query and (re)structure XML data using an XML query language, without having to deal with the underlying SQL tables and query language. The XPERANTO system translates XML-based queries into SQL requests, receives the tabular query results, converts them into XML, and then returns XML documents to the system's users and applications.
... place in scientific, engineering, end even office computing environments, client-server softw... more ... place in scientific, engineering, end even office computing environments, client-server software architectures have become a common approach to providing access to shared services and resources. Most commercial relational ...
XML is rapidly emerging as a standard for exchanging business data on the World Wide Web. For the... more XML is rapidly emerging as a standard for exchanging business data on the World Wide Web. For the foreseeable future, however, most business data will continue to be stored in relational database systems. Consequently, if XML is to fulfill its potential, some mechanism is needed to publish relational data as XML documents. Towards that goal, one of the major challenges is finding a way to efficiently structure and tag data from one or more tables as a hierarchical XML document. Different alternatives are possible depending on when this processing takes place and how much of it is done inside the relational engine. In this paper, we characterize and study the performance of these alternatives. Among other things, we explore the use of new scalar and aggregate functions in SQL for constructing complex XML documents directly in the relational engine. We also explore different execution plans for generating the content of an XML document. The results of an experimental study show that constructing XML documents inside the relational engine can have a significant performance benefit. Our results also show the superiority of having the relational engine use what we call an "outer union plan" to generate the content of an XML document.
Earlier performance studies of client-server data- base systems have investigated algorithms for ... more Earlier performance studies of client-server data- base systems have investigated algorithms for caching locks and data at client worhxtations to reafuce latency and offload the server. These studies have been restricted to algorithms in which d&abase pages that were not in the local client buffer pool or the server buffer pool were read in from disk. In this paper we
A number of recent studies have examined the performance of concurrency control algorithms for da... more A number of recent studies have examined the performance of concurrency control algorithms for database management systems. The results reported to date, rather than being definitive, have tended to be contradictory.
With non-traditional application areas such as engineering design, image/voice data management, s... more With non-traditional application areas such as engineering design, image/voice data management, scientific/statistical applications, and artificial intelligence systems all clamoring for ways to store and efficiently process larger and larger volumes of data, it is clear that traditional database technology has been pushed to its limits. It also seems clear that no single database system will be capable of simultaneously meeting the functionality and performance requirements of such a diverse set of applications. In this paper we describe the initial design of EXODUS, an extensible database system that will facilitate the fast development of high-performance, applicationspecific database systems. EXODUS provides certain kernel facilities, including a versatile storage manager and a type manager. In addition, it provides an architectural framework for building application-specific database systems, tools to partially automate the generation of such systems, and libraries of software components (e.g., access methods) that are likely to be useful for many application domains. Recently, a number of new database system research projects have been initiated to address the needs of this emerging class of applications: EXODUS 1 at the University of Wisconsin [Care85a, Care86], PROBE at CCA [Daya85, Mano86], POSTGRES [Ston86b, Ston86c] at Berkeley, GEMSTONE at Servio Logic Corporation [Cope84, Maie86], STARBURST at IBM Almaden Research Center [Schw86], and GENESIS [Bato86] at the
Abstract The goal of the EXODUS extensible DBMS project is to enable the rapid development of a w... more Abstract The goal of the EXODUS extensible DBMS project is to enable the rapid development of a wide spectrum of high-performance, application-specific database systems EXODUS provides certain kernel facilities for use by all applications and a set of ...
... 4.1.4. Delete The delete operation supports the deletion of N bytes starting at a specified b... more ... 4.1.4. Delete The delete operation supports the deletion of N bytes starting at a specified byte position. ... Again, since the traditional B+ tree dele-tion algorithm removes only one record at a time, it would be unac-ceptably slow for large deletions. ...
A number of recent studies have examined the performance of concurrency control algorithms for da... more A number of recent studies have examined the performance of concurrency control algorithms for database management systems. The results reported to date, rather than being definitive, have tended to be contradictory.
Performance studies of concurrency control algorithms for conventional database systems have show... more Performance studies of concurrency control algorithms for conventional database systems have shown that, under most operating circumstances, locking protocols outperform optimistic techniques. Real-time database systems have special characteristics -timing constraints are associated with transactions, performance criteria are based on satisfaction of these timing constraints, and scheduling algorithms are priority driven. In light of these special characteristics, results regarding the performance of concurrency control algorithms need to be re-evaluated. We show in this paper that the following parameters of the real-time database system -its policy for dealing with transactions whose constraints are not met, its lolowledge of transaction resource requirements, and the availability of resourceshave a significant impact on the relative performance of the concurrency control algorithms. In particular, we demonstrate that under a policy that discards transactions whose constraints are not met, optimistic concurrency control outperforms locking over a wide range of system utilization. We also outline why, for a variety of reasons, optimistic algorithms appear well-suited to real-time database systems. ' We assume here that serializubili?y [Eswa76] is the required level of database correctness.
The VLDB Endowment is a non-profit foundation whose objective is to promote scientific and educat... more The VLDB Endowment is a non-profit foundation whose objective is to promote scientific and educational activities in the area of large-scale data, information, and knowledge management. The Endowment serves as the steering committee for the VLDB conference series. The Endowment also sponsors various scholarly activities. It has established a program that supports summer schools, tutorials, and other training activities of this kind, in countries that could otherwise not afford the expenses for such events. The Endowment is ...
The HiPAC (High Performance ACtive database system) project addresses two critical problems in ti... more The HiPAC (High Performance ACtive database system) project addresses two critical problems in time-constrained data management: the handling of timing constraints in databases, and the avoidance of wasteful polling through the use of situation-action rules that are an integral part of the database and are monitored by the DBMS's condition monitor. A rich knowledge model provides the necessary primitives for definition of timing constraints, situation-action rules, and precipitating events. The execution model allows various coupling modes between transactions, situation evaluations and actions, and provides the framework for correct concurrent execution of transactions and triggered actions. Different approaches to scheduling of time-constrained tasks and transactions are explored and an architecture is being designed with special emphasis on the interaction of the time-constrained, active DBMS and the operating system. Performance models are developed to evaluate the various design alternatives.
In a recent paper, we proposed adding a STOP AFTER clause to SQL to permit the cardinality of a q... more In a recent paper, we proposed adding a STOP AFTER clause to SQL to permit the cardinality of a query result to be explicitly limited by query writers and query tools. We demonstrated the usefulness of having this clause, showed how to extend a traditional cost-based query optimizer to accommodate it, and demonstrated via DB2-based simulations that large performance gains are possible when STOP AFTER queries are explicitly supported by the database engine. In this paper, we present several new strategies for efficiently processing STOP AFTER queries. These strategies, based largely on the use of range partitioning techniques, offer significant additional savings for handling STOP AFTER queries that yield sizeable result sets. We describe classes of queries where such savings would indeed arise and present experimental measurements that show the benefits and tradeoffs associated with the new processing strategies.
... Vivek Maganty$ John Williamst ... Moreover, PEST0 generalizes existing no-tions of jiltenzd b... more ... Vivek Maganty$ John Williamst ... Moreover, PEST0 generalizes existing no-tions of jiltenzd browsing by allowing filters to be spec-ified (1) in place, on the browse structure, (2) on any level(s) of nested sets, and (3) with arbitrarily complex predicates (including explicit and ...
M. J. Carey, L. M. Haas, P. M. Schwarz, M. Arya, W. E Cody, R. Fagin, M. Flickner, A. W. Luniewsk... more M. J. Carey, L. M. Haas, P. M. Schwarz, M. Arya, W. E Cody, R. Fagin, M. Flickner, A. W. Luniewski, ... W. Niblack, D. Petkovic, J. Thomas, J. H. Williams and EL Wimmers ... IBM Almaden Research Center, San Jose, CA 95 120
IEEE Transactions on Knowledge and Data Engineering, 1990
... Manuscript received August I, 1989: revised December 4, 1989. LM Haas, GM Lohman. J. McPherso... more ... Manuscript received August I, 1989: revised December 4, 1989. LM Haas, GM Lohman. J. McPherson, PF Wilms, G. Lapis, B. Lindsay, and H. Pirahesh are with IBM Almaden Research Center. San Jose. CA 95120. W. Chang is with Oracle Corporation, Belmont, CA 94002. ...
Since its introduction, XML, the eXtended Markup Language, has quickly emerged as the universal f... more Since its introduction, XML, the eXtended Markup Language, has quickly emerged as the universal format for publishing and exchanging data in the World Wide Web. As a result, data sources, including object-relational databases, are now faced with a new class of users: clients and customers who would like to deal directly with XML data rather than being forced to deal with the data source's particular (e.g., object-relational) schema and query language. The goal of the XPERANTO project at the IBM Almaden Research Center is to serve as a middleware layer that supports the publishing of XML data to this class of users. XPERANTO provides a uniform, XML-based query interface over an object-relational database that allows users to query and (re)structure the contents of the database as XML data, ignoring the underlying SQL tables and query language. In this paper, we give an overview of the XPERANTO system prototype, explaining how it translates XML-based queries into SQL requests, receives and then structures the tabular query results, and finally returns XML documents to the system's users and applications.
Earlier studies have observed that in moderately-loaded real-time database systems. using an Earl... more Earlier studies have observed that in moderately-loaded real-time database systems. using an Earliest Deadline policy to schedule tasks results in the fewest missed deadlines. When the real-time system is overloa&d, however. an Earliest Deadline schedule perfoms worse than most other policies. This is due to are close to m i s s i i their deadliies. In this paper, we present a new piority assignment algorithm called Adaptive Earliest Deadlinc (AED), which features a feedback control mechanism that detects overload conditions and modifies transaction priaity assignments -1y.
Priority in DBMS Resource Scheduling Michael J. Carey Rajiv Jauhari MironLivny Computer Sciences ... more Priority in DBMS Resource Scheduling Michael J. Carey Rajiv Jauhari MironLivny Computer Sciences Department University of Wisconsin Madison, WI 53706 ABSTRACTIn this paper, we address the problem of priority scheduling in a database management system. ...
The eXtended Markup Language (XML) is quickly emerging as the universal format for publishing and... more The eXtended Markup Language (XML) is quickly emerging as the universal format for publishing and exchanging data on the World Wide Web. As a result, data sources, including object-relational databases, are now faced with a new class of users and applications; customers and programs that would like to deal directly with XML data rather than being forced to deal with the data source's particular (e.g., objectrelational) schema and query language. The goal of the XPERANTO middleware project is to support this new class of users and applications. XPERANTO does this by providing query-able "XML Views" over the underlying objectrelational database. Users can then query and (re)structure XML data using an XML query language, without having to deal with the underlying SQL tables and query language. The XPERANTO system translates XML-based queries into SQL requests, receives the tabular query results, converts them into XML, and then returns XML documents to the system's users and applications.
... place in scientific, engineering, end even office computing environments, client-server softw... more ... place in scientific, engineering, end even office computing environments, client-server software architectures have become a common approach to providing access to shared services and resources. Most commercial relational ...
XML is rapidly emerging as a standard for exchanging business data on the World Wide Web. For the... more XML is rapidly emerging as a standard for exchanging business data on the World Wide Web. For the foreseeable future, however, most business data will continue to be stored in relational database systems. Consequently, if XML is to fulfill its potential, some mechanism is needed to publish relational data as XML documents. Towards that goal, one of the major challenges is finding a way to efficiently structure and tag data from one or more tables as a hierarchical XML document. Different alternatives are possible depending on when this processing takes place and how much of it is done inside the relational engine. In this paper, we characterize and study the performance of these alternatives. Among other things, we explore the use of new scalar and aggregate functions in SQL for constructing complex XML documents directly in the relational engine. We also explore different execution plans for generating the content of an XML document. The results of an experimental study show that constructing XML documents inside the relational engine can have a significant performance benefit. Our results also show the superiority of having the relational engine use what we call an "outer union plan" to generate the content of an XML document.
Earlier performance studies of client-server data- base systems have investigated algorithms for ... more Earlier performance studies of client-server data- base systems have investigated algorithms for caching locks and data at client worhxtations to reafuce latency and offload the server. These studies have been restricted to algorithms in which d&abase pages that were not in the local client buffer pool or the server buffer pool were read in from disk. In this paper we
A number of recent studies have examined the performance of concurrency control algorithms for da... more A number of recent studies have examined the performance of concurrency control algorithms for database management systems. The results reported to date, rather than being definitive, have tended to be contradictory.
With non-traditional application areas such as engineering design, image/voice data management, s... more With non-traditional application areas such as engineering design, image/voice data management, scientific/statistical applications, and artificial intelligence systems all clamoring for ways to store and efficiently process larger and larger volumes of data, it is clear that traditional database technology has been pushed to its limits. It also seems clear that no single database system will be capable of simultaneously meeting the functionality and performance requirements of such a diverse set of applications. In this paper we describe the initial design of EXODUS, an extensible database system that will facilitate the fast development of high-performance, applicationspecific database systems. EXODUS provides certain kernel facilities, including a versatile storage manager and a type manager. In addition, it provides an architectural framework for building application-specific database systems, tools to partially automate the generation of such systems, and libraries of software components (e.g., access methods) that are likely to be useful for many application domains. Recently, a number of new database system research projects have been initiated to address the needs of this emerging class of applications: EXODUS 1 at the University of Wisconsin [Care85a, Care86], PROBE at CCA [Daya85, Mano86], POSTGRES [Ston86b, Ston86c] at Berkeley, GEMSTONE at Servio Logic Corporation [Cope84, Maie86], STARBURST at IBM Almaden Research Center [Schw86], and GENESIS [Bato86] at the
Abstract The goal of the EXODUS extensible DBMS project is to enable the rapid development of a w... more Abstract The goal of the EXODUS extensible DBMS project is to enable the rapid development of a wide spectrum of high-performance, application-specific database systems EXODUS provides certain kernel facilities for use by all applications and a set of ...
... 4.1.4. Delete The delete operation supports the deletion of N bytes starting at a specified b... more ... 4.1.4. Delete The delete operation supports the deletion of N bytes starting at a specified byte position. ... Again, since the traditional B+ tree dele-tion algorithm removes only one record at a time, it would be unac-ceptably slow for large deletions. ...
A number of recent studies have examined the performance of concurrency control algorithms for da... more A number of recent studies have examined the performance of concurrency control algorithms for database management systems. The results reported to date, rather than being definitive, have tended to be contradictory.
Performance studies of concurrency control algorithms for conventional database systems have show... more Performance studies of concurrency control algorithms for conventional database systems have shown that, under most operating circumstances, locking protocols outperform optimistic techniques. Real-time database systems have special characteristics -timing constraints are associated with transactions, performance criteria are based on satisfaction of these timing constraints, and scheduling algorithms are priority driven. In light of these special characteristics, results regarding the performance of concurrency control algorithms need to be re-evaluated. We show in this paper that the following parameters of the real-time database system -its policy for dealing with transactions whose constraints are not met, its lolowledge of transaction resource requirements, and the availability of resourceshave a significant impact on the relative performance of the concurrency control algorithms. In particular, we demonstrate that under a policy that discards transactions whose constraints are not met, optimistic concurrency control outperforms locking over a wide range of system utilization. We also outline why, for a variety of reasons, optimistic algorithms appear well-suited to real-time database systems. ' We assume here that serializubili?y [Eswa76] is the required level of database correctness.
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Papers by Michael Carey