Pub Date : 1995-03-06DOI: 10.1109/ICDE.1995.380350
C. Hofmeister, R. Nord, Dilip Soni
The software architecture of a system describes how it is decomposed into components, how these components are interconnected, and how they communicate and interact with each other and with the environment. Software architecture represents critical, system-wide design decisions which affect quality, reconfigurability and reuse, and the cost for development and maintenance. In order to understand architecture as it is practised in the real world, we conducted a survey of a variety of industrial software systems. Our survey revealed the need for rigorous descriptions, systematic techniques, and well-defined processes to make architecture-level software development an engineering practice rather than an art.<>
{"title":"An industrial perspective of software architecture","authors":"C. Hofmeister, R. Nord, Dilip Soni","doi":"10.1109/ICDE.1995.380350","DOIUrl":"https://doi.org/10.1109/ICDE.1995.380350","url":null,"abstract":"The software architecture of a system describes how it is decomposed into components, how these components are interconnected, and how they communicate and interact with each other and with the environment. Software architecture represents critical, system-wide design decisions which affect quality, reconfigurability and reuse, and the cost for development and maintenance. In order to understand architecture as it is practised in the real world, we conducted a survey of a variety of industrial software systems. Our survey revealed the need for rigorous descriptions, systematic techniques, and well-defined processes to make architecture-level software development an engineering practice rather than an art.<<ETX>>","PeriodicalId":184415,"journal":{"name":"Proceedings of the Eleventh International Conference on Data Engineering","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133278180","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}
Pub Date : 1995-03-06DOI: 10.1109/ICDE.1995.380385
J. Zhao, A. Segev, A. Chatterjee
We describe a manufacturing environment where, driven by market forces, organizations cooperate as well as compete with one another. We argue that a federated database system (FDBS) is appropriate for such an environment. Contrary to conventional wisdom, complete transparency, assumed desirable and mandatory in distributed database systems, is neither desirable nor feasible in this environment. We propose a new approach that is based on schema coordination rather than integration under which each component database is free to change its data structure, attribute naming, and data semantics. A federated metadata model based on the notion of universal relation is introduced for the FDBS. We also develop the query processing paradigm, and present procedures for query transformation and heterogeneity resolution.<>
{"title":"A universal relation approach to federated database management","authors":"J. Zhao, A. Segev, A. Chatterjee","doi":"10.1109/ICDE.1995.380385","DOIUrl":"https://doi.org/10.1109/ICDE.1995.380385","url":null,"abstract":"We describe a manufacturing environment where, driven by market forces, organizations cooperate as well as compete with one another. We argue that a federated database system (FDBS) is appropriate for such an environment. Contrary to conventional wisdom, complete transparency, assumed desirable and mandatory in distributed database systems, is neither desirable nor feasible in this environment. We propose a new approach that is based on schema coordination rather than integration under which each component database is free to change its data structure, attribute naming, and data semantics. A federated metadata model based on the notion of universal relation is introduced for the FDBS. We also develop the query processing paradigm, and present procedures for query transformation and heterogeneity resolution.<<ETX>>","PeriodicalId":184415,"journal":{"name":"Proceedings of the Eleventh International Conference on Data Engineering","volume":"148 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124138042","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}
Pub Date : 1995-03-06DOI: 10.1109/ICDE.1995.380363
M. García-Solaco, F. Saltor, M. Castellanos
The process of integrating the schemas of several databases into an integrated schema is not easy, due to semantic heterogeneities. We present a method/sup 1/ to detect class similarities by following a strategy and applying comparison criteria, that exploits the semantically rich structures of the schemas (previously enriched), along both the generalization/specialization and the aggregation dimensions. Relaxations may be applied to conform a pair of classes, resulting in penalizations in the computation of the degree of similarity. Our approach needs less comparisons than methods based on attribute comparison.<>
{"title":"A structure based schema integration methodology","authors":"M. García-Solaco, F. Saltor, M. Castellanos","doi":"10.1109/ICDE.1995.380363","DOIUrl":"https://doi.org/10.1109/ICDE.1995.380363","url":null,"abstract":"The process of integrating the schemas of several databases into an integrated schema is not easy, due to semantic heterogeneities. We present a method/sup 1/ to detect class similarities by following a strategy and applying comparison criteria, that exploits the semantically rich structures of the schemas (previously enriched), along both the generalization/specialization and the aggregation dimensions. Relaxations may be applied to conform a pair of classes, resulting in penalizations in the computation of the degree of similarity. Our approach needs less comparisons than methods based on attribute comparison.<<ETX>>","PeriodicalId":184415,"journal":{"name":"Proceedings of the Eleventh International Conference on Data Engineering","volume":"47 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114332082","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}
Pub Date : 1995-03-06DOI: 10.1109/ICDE.1995.380354
Catherine Hamon, A. M. Keller
We describe a two-level client-side cache for composite objects mapped as views of a relational database. A semantic model, the Structural Model, is used to specify joins on the relational database that are useful for defining composite objects. The lower level of the cache contains the tuples from each relation that have already been loaded into memory. These tuples are linked together from relation to relation according to the joins of the structural model. This level of the cache is shared among all applications using the data on this client. The higher level of the cache contains composed objects of data extracted from the lower level cache. This level of the cache uses the object schema of a single application, and the data is copied from the lower level cache for convenient access by the application. This two-level cache is designed as part of the Penguin system, which supports multiple applications, each with its own object schema, to share data stored in a common relational database.<>
{"title":"Two-level caching of composite object views of relational databases","authors":"Catherine Hamon, A. M. Keller","doi":"10.1109/ICDE.1995.380354","DOIUrl":"https://doi.org/10.1109/ICDE.1995.380354","url":null,"abstract":"We describe a two-level client-side cache for composite objects mapped as views of a relational database. A semantic model, the Structural Model, is used to specify joins on the relational database that are useful for defining composite objects. The lower level of the cache contains the tuples from each relation that have already been loaded into memory. These tuples are linked together from relation to relation according to the joins of the structural model. This level of the cache is shared among all applications using the data on this client. The higher level of the cache contains composed objects of data extracted from the lower level cache. This level of the cache uses the object schema of a single application, and the data is copied from the lower level cache for convenient access by the application. This two-level cache is designed as part of the Penguin system, which supports multiple applications, each with its own object schema, to share data stored in a common relational database.<<ETX>>","PeriodicalId":184415,"journal":{"name":"Proceedings of the Eleventh International Conference on Data Engineering","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123459227","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}
Pub Date : 1995-03-06DOI: 10.1109/ICDE.1995.380365
I. Song, Trevor H. Jones
We review a set of rules identifying which combinations of ternary and binary relationships can be combined simultaneously in semantically related situations. We investigate the effect of these rules on decomposing ternary relationships to simpler, multiple binary relationships. We also discuss the relevance of these decomposition strategies to ER modeling. We show that if at least one 1:1 or 1:M binary constraint can be identified within the construct of the ternary itself, then any ternary relationship can be decomposed to a binary format. From this methodology we construct a heuristic-the Constrained Ternary Decomposition (CTD) rule.<>
{"title":"Ternary relationship decomposition strategies based on binary imposition rules","authors":"I. Song, Trevor H. Jones","doi":"10.1109/ICDE.1995.380365","DOIUrl":"https://doi.org/10.1109/ICDE.1995.380365","url":null,"abstract":"We review a set of rules identifying which combinations of ternary and binary relationships can be combined simultaneously in semantically related situations. We investigate the effect of these rules on decomposing ternary relationships to simpler, multiple binary relationships. We also discuss the relevance of these decomposition strategies to ER modeling. We show that if at least one 1:1 or 1:M binary constraint can be identified within the construct of the ternary itself, then any ternary relationship can be decomposed to a binary format. From this methodology we construct a heuristic-the Constrained Ternary Decomposition (CTD) rule.<<ETX>>","PeriodicalId":184415,"journal":{"name":"Proceedings of the Eleventh International Conference on Data Engineering","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125504541","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}
Pub Date : 1995-03-06DOI: 10.1109/ICDE.1995.380392
S. Chaudhuri, R. Krishnamurthy, S. Potamianos, Kyuseok Shim
While much work has addressed the problem of maintaining materialized views, the important question of optimizing queries in the presence of materialised views has not been resolved. In this paper, we analyze the optimization question and provide a comprehensive and efficient solution. Our solution has the desirable property that it is a simple generalization of the traditional query optimization algorithm.<>
{"title":"Optimizing queries with materialized views","authors":"S. Chaudhuri, R. Krishnamurthy, S. Potamianos, Kyuseok Shim","doi":"10.1109/ICDE.1995.380392","DOIUrl":"https://doi.org/10.1109/ICDE.1995.380392","url":null,"abstract":"While much work has addressed the problem of maintaining materialized views, the important question of optimizing queries in the presence of materialised views has not been resolved. In this paper, we analyze the optimization question and provide a comprehensive and efficient solution. Our solution has the desirable property that it is a simple generalization of the traditional query optimization algorithm.<<ETX>>","PeriodicalId":184415,"journal":{"name":"Proceedings of the Eleventh International Conference on Data Engineering","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121616178","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}
Pub Date : 1995-03-06DOI: 10.1109/ICDE.1995.380410
Mark L. McAuliffe, M. Solomon
Persistent object-oriented applications that traverse large object graphs can improve their performance by caching objects in main memory while they are being used. While caching offers large performance benefits, the techniques used to locate these cached objects in memory can still impede the application's performance. We present the results of a trace-based simulation study of pointer swizzling techniques (techniques for reducing the cost of access to cached objects). We used traces derived from actual persistent programs to find a class of swizzling techniques that performs well, yet permits changes to the contents of in-memory object caches over the lifetime of an application. Our study demonstrates the superiority of a class of techniques known as "indirect swizzling" for a variety of workloads and system configurations.<>
{"title":"A trace-based simulation of pointer swizzling techniques","authors":"Mark L. McAuliffe, M. Solomon","doi":"10.1109/ICDE.1995.380410","DOIUrl":"https://doi.org/10.1109/ICDE.1995.380410","url":null,"abstract":"Persistent object-oriented applications that traverse large object graphs can improve their performance by caching objects in main memory while they are being used. While caching offers large performance benefits, the techniques used to locate these cached objects in memory can still impede the application's performance. We present the results of a trace-based simulation study of pointer swizzling techniques (techniques for reducing the cost of access to cached objects). We used traces derived from actual persistent programs to find a class of swizzling techniques that performs well, yet permits changes to the contents of in-memory object caches over the lifetime of an application. Our study demonstrates the superiority of a class of techniques known as \"indirect swizzling\" for a variety of workloads and system configurations.<<ETX>>","PeriodicalId":184415,"journal":{"name":"Proceedings of the Eleventh International Conference on Data Engineering","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122452642","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}
This paper presents a comprehensive procedure to design multimedia storage systems for on-demand playback. The design stresses effective utilization of disk bandwidth with minimal data buffer to minimize overall system costs. The design procedure is most distinctive in the following two aspects: it bases on a tight upper bound of the lumped disk seek time for the Scan disk scheduling algorithm to achieve effective utilization of disk bandwidth; it starts with a general two-level hierarchical disk array structure to derive the optimal configuration for specific requirements.<>
{"title":"Design of multimedia storage systems for on-demand playback","authors":"Yen-Jen Oyang, Meng-Huang Lee, Chun-Hung Wen, Chih-Yuan Cheng","doi":"10.1109/ICDE.1995.380368","DOIUrl":"https://doi.org/10.1109/ICDE.1995.380368","url":null,"abstract":"This paper presents a comprehensive procedure to design multimedia storage systems for on-demand playback. The design stresses effective utilization of disk bandwidth with minimal data buffer to minimize overall system costs. The design procedure is most distinctive in the following two aspects: it bases on a tight upper bound of the lumped disk seek time for the Scan disk scheduling algorithm to achieve effective utilization of disk bandwidth; it starts with a general two-level hierarchical disk array structure to derive the optimal configuration for specific requirements.<<ETX>>","PeriodicalId":184415,"journal":{"name":"Proceedings of the Eleventh International Conference on Data Engineering","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122429196","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}
Pub Date : 1995-03-06DOI: 10.1109/ICDE.1995.380361
P. Haas, A. Swami
We compare empirically the cost of estimating the selectivity of a star join using the sampling-based t-cross procedure to the cost of computing the join and obtaining the exact answer. The relative cost of sampling can be excessive when a join attribute value exhibits "heterogeneous skew." To alleviate this problem, we propose Algorithm TCM, a modified version of t-cross that incorporates "augmented frequent value" (AFV) statistics. We provide a sampling-based method for estimating AFV statistics that does not require indexes on attribute values, requires only one pass though each relation, and uses an amount of memory much smaller than the size of a relation. Our experiments show that the use of estimated AFV statistics can reduce the relative cost of sampling by orders of magnitude. We also show that use of estimated AFV statistics can reduce the relative error of the classical System R selectivity formula.<>
{"title":"Sampling-based selectivity estimation for joins using augmented frequent value statistics","authors":"P. Haas, A. Swami","doi":"10.1109/ICDE.1995.380361","DOIUrl":"https://doi.org/10.1109/ICDE.1995.380361","url":null,"abstract":"We compare empirically the cost of estimating the selectivity of a star join using the sampling-based t-cross procedure to the cost of computing the join and obtaining the exact answer. The relative cost of sampling can be excessive when a join attribute value exhibits \"heterogeneous skew.\" To alleviate this problem, we propose Algorithm TCM, a modified version of t-cross that incorporates \"augmented frequent value\" (AFV) statistics. We provide a sampling-based method for estimating AFV statistics that does not require indexes on attribute values, requires only one pass though each relation, and uses an amount of memory much smaller than the size of a relation. Our experiments show that the use of estimated AFV statistics can reduce the relative cost of sampling by orders of magnitude. We also show that use of estimated AFV statistics can reduce the relative error of the classical System R selectivity formula.<<ETX>>","PeriodicalId":184415,"journal":{"name":"Proceedings of the Eleventh International Conference on Data Engineering","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132670848","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}
Pub Date : 1995-03-06DOI: 10.1109/ICDE.1995.380369
S. Lau, John C.S. Lui, P. Wong
We consider a storage server architecture for multimedia information systems. While most other works on multimedia storage servers assume on-line disk storage, we consider a two-tier storage architecture with a robotic tape library as the vast near-line storage and on-line disks as the front-line storage. Magnetic tapes are cheaper, more robust, and have a larger capacity; hence they are more cost effective for large scale storage systems (e.g., video on demand (VOD) systems may store tens of thousands of videos). We study in detail the design issues of the tape subsystem and propose some novel tape scheduling algorithms which give faster response and require less disk buffering.<>
{"title":"A cost-effective near-line storage server for multimedia system","authors":"S. Lau, John C.S. Lui, P. Wong","doi":"10.1109/ICDE.1995.380369","DOIUrl":"https://doi.org/10.1109/ICDE.1995.380369","url":null,"abstract":"We consider a storage server architecture for multimedia information systems. While most other works on multimedia storage servers assume on-line disk storage, we consider a two-tier storage architecture with a robotic tape library as the vast near-line storage and on-line disks as the front-line storage. Magnetic tapes are cheaper, more robust, and have a larger capacity; hence they are more cost effective for large scale storage systems (e.g., video on demand (VOD) systems may store tens of thousands of videos). We study in detail the design issues of the tape subsystem and propose some novel tape scheduling algorithms which give faster response and require less disk buffering.<<ETX>>","PeriodicalId":184415,"journal":{"name":"Proceedings of the Eleventh International Conference on Data Engineering","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1995-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117165593","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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