Environments where read-only transactions predominate update transactions are considered. The notion of a group in replicated databases, the recognition of which maximizes the data availability for read-only transactions in error-prone environments, is developed. It is shown that the group identification problem is NP-complete. Replica control algorithms that attempt to approximately determine groups are presented. In one algorithm, groups are determined dynamically; in the other techniques, groups are predefined. It is shown formally that both approaches yield algorithms that preserve the consistency of the database. In the environments considered, the approaches presented are shown to yield significant improvements over other fault-tolerant replica control algorithms.<>
{"title":"Read-only transactions in partitioned replicated databases","authors":"K. Brahmadathan, K. Ramarao","doi":"10.1109/ICDE.1989.47258","DOIUrl":"https://doi.org/10.1109/ICDE.1989.47258","url":null,"abstract":"Environments where read-only transactions predominate update transactions are considered. The notion of a group in replicated databases, the recognition of which maximizes the data availability for read-only transactions in error-prone environments, is developed. It is shown that the group identification problem is NP-complete. Replica control algorithms that attempt to approximately determine groups are presented. In one algorithm, groups are determined dynamically; in the other techniques, groups are predefined. It is shown formally that both approaches yield algorithms that preserve the consistency of the database. In the environments considered, the approaches presented are shown to yield significant improvements over other fault-tolerant replica control algorithms.<<ETX>>","PeriodicalId":329505,"journal":{"name":"[1989] Proceedings. Fifth International Conference on Data Engineering","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131668260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A framework is presented for analysis of time-critical scheduling algorithms. The main assumptions are analyzed behind real-time scheduling and concurrency control algorithms, and a unified approach is proposed. Two main classes of schedulers are identified according to the availability of information about resource requirements and execution times: conflict-resolving schedulers resolve conflicts at run-time, and hence can only produce a sequence of operations satisfying task priorities and resource constraints; and conflict-avoiding schedulers determine resource requirements and expected execution times through offline transaction-class preanalysis and produce a complete time-critical schedule satisfying both timing and resource constraints. For the latter case, the resolution of overload is essential. Examples are given to illustrate the framework and the main classes of scheduling algorithms.<>
{"title":"Time-critical database scheduling: a framework for integrating real-time scheduling and concurrency control","authors":"A. Buchmann, Dennis R. McCarthy, M. Hsu, U. Dayal","doi":"10.1109/ICDE.1989.47251","DOIUrl":"https://doi.org/10.1109/ICDE.1989.47251","url":null,"abstract":"A framework is presented for analysis of time-critical scheduling algorithms. The main assumptions are analyzed behind real-time scheduling and concurrency control algorithms, and a unified approach is proposed. Two main classes of schedulers are identified according to the availability of information about resource requirements and execution times: conflict-resolving schedulers resolve conflicts at run-time, and hence can only produce a sequence of operations satisfying task priorities and resource constraints; and conflict-avoiding schedulers determine resource requirements and expected execution times through offline transaction-class preanalysis and produce a complete time-critical schedule satisfying both timing and resource constraints. For the latter case, the resolution of overload is essential. Examples are given to illustrate the framework and the main classes of scheduling algorithms.<<ETX>>","PeriodicalId":329505,"journal":{"name":"[1989] Proceedings. Fifth International Conference on Data Engineering","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132259255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The authors argue for implementing composition as a primitive operation and present a single-sided composition algorithm that performs join protection and duplicate elimination as one unified operation. They report experimental results that show an operating region in which this algorithm outperforms composition by the standard method. This operating region is characterized by a join result many times larger than the source relations, and many duplicates after projection over the nonjoin attributes. This occurs, for example, in deductive databases when computing transitive closures of dense graphs.<>
{"title":"Composition of database relations","authors":"R. Agrawal, Shaul Dar, H. Jagadish","doi":"10.1109/ICDE.1989.47205","DOIUrl":"https://doi.org/10.1109/ICDE.1989.47205","url":null,"abstract":"The authors argue for implementing composition as a primitive operation and present a single-sided composition algorithm that performs join protection and duplicate elimination as one unified operation. They report experimental results that show an operating region in which this algorithm outperforms composition by the standard method. This operating region is characterized by a join result many times larger than the source relations, and many duplicates after projection over the nonjoin attributes. This occurs, for example, in deductive databases when computing transitive closures of dense graphs.<<ETX>>","PeriodicalId":329505,"journal":{"name":"[1989] Proceedings. Fifth International Conference on Data Engineering","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134104925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is argued that those areas of data engineering research which are based on the assumption that communication bandwidth is a constraint, should be investigated. Some additional distributed database issues that require reinvestigation include concurrency control, network partitioning, backup storage and recovery algorithms. With the availability of increased bandwidth, global flooding of information can result in lower processing times than conventional approaches. Hence, broadcast-based solutions which continuously inform the various sites of the system status and data modifications need to be reconsidered. Novel transmission rates also invalidate old assumptions.<>
{"title":"Communications issues in data engineering: 'have bandwidth-will move data'","authors":"O. Frieder","doi":"10.1109/ICDE.1989.47276","DOIUrl":"https://doi.org/10.1109/ICDE.1989.47276","url":null,"abstract":"It is argued that those areas of data engineering research which are based on the assumption that communication bandwidth is a constraint, should be investigated. Some additional distributed database issues that require reinvestigation include concurrency control, network partitioning, backup storage and recovery algorithms. With the availability of increased bandwidth, global flooding of information can result in lower processing times than conventional approaches. Hence, broadcast-based solutions which continuously inform the various sites of the system status and data modifications need to be reconsidered. Novel transmission rates also invalidate old assumptions.<<ETX>>","PeriodicalId":329505,"journal":{"name":"[1989] Proceedings. Fifth International Conference on Data Engineering","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133030460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An algorithm is introduced to evaluate queries in a massively parallel computing environment under an object-based representation of a database. By distributing facts into connected networks of processing elements, it is shown that parallel execution of a query can be achieved in a cooperative way, so that the conventional tuple-by-tuple evaluation can be avoided. Furthermore, it is shown that dependency imposed by shared variables is not a major problem in achieving AND parallelism any longer. Although only a single query is considered, the evaluation scheme can be extended to multiple queries with multiple query networks and with replication of counters in the fact network.<>
本文介绍了在大规模并行计算环境中，在基于对象的数据库表示法下评估查询的算法。通过将事实分布到处理元素的连接网络中，可以证明查询的并行执行可以以合作的方式实现，从而避免了传统的逐个元组评估。此外，研究还表明，共享变量带来的依赖性不再是实现 AND 并行性的主要问题。虽然只考虑了单个查询，但该评估方案可以扩展到具有多个查询网络和在事实网络中复制计数器的多个查询。
{"title":"An object-based query evaluation scheme for deductive databases in massively parallel computing environment","authors":"Won S. Lee, P. Sheu","doi":"10.1109/ICDE.1989.47255","DOIUrl":"https://doi.org/10.1109/ICDE.1989.47255","url":null,"abstract":"An algorithm is introduced to evaluate queries in a massively parallel computing environment under an object-based representation of a database. By distributing facts into connected networks of processing elements, it is shown that parallel execution of a query can be achieved in a cooperative way, so that the conventional tuple-by-tuple evaluation can be avoided. Furthermore, it is shown that dependency imposed by shared variables is not a major problem in achieving AND parallelism any longer. Although only a single query is considered, the evaluation scheme can be extended to multiple queries with multiple query networks and with replication of counters in the fact network.<<ETX>>","PeriodicalId":329505,"journal":{"name":"[1989] Proceedings. Fifth International Conference on Data Engineering","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127728711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tangram, an environment for modeling which is under development at UCLA, is discussed. One of the driving concepts behind Tangram has been the combination of large-scale data access and data reduction with a powerful programming environment. The Tangram environment is based on PROLOG, extending it with a number of features, including process management, distributed database access, and generalized stream processing. The authors describe the Tangram stream processor, the part of the Tangram environment performing query processing on large streams of data. The paradigm of transducers on streams is used throughout this system, providing a database flow computation capability.<>
{"title":"The Tangram stream query processing system","authors":"D. S. Parker, R. Muntz, H. L. Chau","doi":"10.1109/ICDE.1989.47262","DOIUrl":"https://doi.org/10.1109/ICDE.1989.47262","url":null,"abstract":"Tangram, an environment for modeling which is under development at UCLA, is discussed. One of the driving concepts behind Tangram has been the combination of large-scale data access and data reduction with a powerful programming environment. The Tangram environment is based on PROLOG, extending it with a number of features, including process management, distributed database access, and generalized stream processing. The authors describe the Tangram stream processor, the part of the Tangram environment performing query processing on large streams of data. The paradigm of transducers on streams is used throughout this system, providing a database flow computation capability.<<ETX>>","PeriodicalId":329505,"journal":{"name":"[1989] Proceedings. Fifth International Conference on Data Engineering","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115266085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A direct extension to the counting method is presented which can deal efficiently with both acyclic and cyclic relations. The extension to cycle cases, called the synchronized counting method, is simulated and studied using a Petri net model. Worst-case analysis shows that n/sup 2/ semijoin operations are required, where n is the number of nodes in the graph representing the relevant part of the input relations. The algorithm is shown to be sound and complete, and a comparison with other methods in the literature is included.<>
{"title":"Synchronized counting method","authors":"H. Aly, Z. M. Özsoyoglu","doi":"10.1109/ICDE.1989.47237","DOIUrl":"https://doi.org/10.1109/ICDE.1989.47237","url":null,"abstract":"A direct extension to the counting method is presented which can deal efficiently with both acyclic and cyclic relations. The extension to cycle cases, called the synchronized counting method, is simulated and studied using a Petri net model. Worst-case analysis shows that n/sup 2/ semijoin operations are required, where n is the number of nodes in the graph representing the relevant part of the input relations. The algorithm is shown to be sound and complete, and a comparison with other methods in the literature is included.<<ETX>>","PeriodicalId":329505,"journal":{"name":"[1989] Proceedings. Fifth International Conference on Data Engineering","volume":"372 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115566396","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Two different schemes are presented to make commit protocols fault-tolerant. The first scheme ensures that a failed site can directly recover to a state which is consistent with all other sites, using only its local information. This scheme can only make commit protocols resilient to a single site failure. The second scheme ensures that failed sites can recover to a state consistent with all others with as few information exchanges as possible. This scheme can make commit protocols resilient to any type of site failure.<>
{"title":"Fault tolerant commit protocols","authors":"S. Yuan, P. Jalote","doi":"10.1109/ICDE.1989.47227","DOIUrl":"https://doi.org/10.1109/ICDE.1989.47227","url":null,"abstract":"Two different schemes are presented to make commit protocols fault-tolerant. The first scheme ensures that a failed site can directly recover to a state which is consistent with all other sites, using only its local information. This scheme can only make commit protocols resilient to a single site failure. The second scheme ensures that failed sites can recover to a state consistent with all others with as few information exchanges as possible. This scheme can make commit protocols resilient to any type of site failure.<<ETX>>","PeriodicalId":329505,"journal":{"name":"[1989] Proceedings. Fifth International Conference on Data Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116090215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Four spatial data access methods, R-trees, K-D-B-trees, R+trees, and 2-D-Isam, have been implemented within a preliminary version of the POSTGRES DBMS (database management system). These access methods have been tested over a range of shapes and sizes of two-dimensional objects and for a range of logical page sizes. The CPU time, number of disk reads and writes, and the resulting tree sizes have been tabulated for insert and retrieve operations. It is concluded that R-trees provide the best tradeoff between performance and implementation complexity and that choice of implementation is crucial to the performance of all the methods investigated.<>
四种空间数据访问方法，R-树，k - d - b -树，R+树和2-D-Isam，已经在POSTGRES DBMS(数据库管理系统)的初步版本中实现。这些访问方法已经在二维对象的各种形状和大小以及各种逻辑页面大小上进行了测试。CPU时间、磁盘读写次数以及生成的树大小已被制成表格，用于插入和检索操作。结论是，r树提供了性能和实现复杂性之间的最佳权衡，实现的选择对所研究的所有方法的性能至关重要。
{"title":"An implementation and performance analysis of spatial data access methods","authors":"Derek Greene","doi":"10.1109/ICDE.1989.47268","DOIUrl":"https://doi.org/10.1109/ICDE.1989.47268","url":null,"abstract":"Four spatial data access methods, R-trees, K-D-B-trees, R+trees, and 2-D-Isam, have been implemented within a preliminary version of the POSTGRES DBMS (database management system). These access methods have been tested over a range of shapes and sizes of two-dimensional objects and for a range of logical page sizes. The CPU time, number of disk reads and writes, and the resulting tree sizes have been tabulated for insert and retrieve operations. It is concluded that R-trees provide the best tradeoff between performance and implementation complexity and that choice of implementation is crucial to the performance of all the methods investigated.<<ETX>>","PeriodicalId":329505,"journal":{"name":"[1989] Proceedings. Fifth International Conference on Data Engineering","volume":"5a 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128201375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A model of access authorization is described for relational databases. In this model access permissions are a form of database knowledge, from which access permissions that apply to specific requests are inferred. Database access is specified in terms of views: a set of views is defined, and each user is granted permission to access one or more views. Users direct queries at the actual database, not at any particular view. When a request to access a view is presented to the database system, the system derives views of the request that are views of the views to which the user has access permission and presents the user only with these views. The model represents the definitions of views in special metarelations and extends standard algebraic operators to these relations.<>
{"title":"An access authorization model for relational databases based on algebraic manipulation of view definitions","authors":"Amihai Motro","doi":"10.1109/ICDE.1989.47234","DOIUrl":"https://doi.org/10.1109/ICDE.1989.47234","url":null,"abstract":"A model of access authorization is described for relational databases. In this model access permissions are a form of database knowledge, from which access permissions that apply to specific requests are inferred. Database access is specified in terms of views: a set of views is defined, and each user is granted permission to access one or more views. Users direct queries at the actual database, not at any particular view. When a request to access a view is presented to the database system, the system derives views of the request that are views of the views to which the user has access permission and presents the user only with these views. The model represents the definitions of views in special metarelations and extends standard algebraic operators to these relations.<<ETX>>","PeriodicalId":329505,"journal":{"name":"[1989] Proceedings. Fifth International Conference on Data Engineering","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1989-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125129424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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