We study the problem of continuous relational query processing in Internet-scale overlay networks realized by distributed hash tables. We concentrate on the case of continuous two-way equi-join queries. Joins are hard to evaluate in a distributed continuous query environment because data from more than one relations is needed, and this data is inserted in the network asynchronously. Each time a new tuple is inserted, the network nodes have to cooperate to check if this tuple can contribute to the satisfaction of a query when combined with previously inserted tuples. We propose a series of algorithms that initially index queries at network nodes using hashing. Then, they exploit the values of join attributes in incoming tuples to rewrite the given queries into simpler ones, and reindex them in the network where they might be satisfied by existing or future tuples. We present a detailed experimental evaluation in a simulated environment and we show that our algorithms are scalable, balance the storage and query processing load and keep the network traffic low.
{"title":"Distributed Evaluation of Continuous Equi-join Queries over Large Structured Overlay Networks","authors":"Stratos Idreos, Christos Tryfonopoulos, Manolis Koubarakis","doi":"10.1109/ICDE.2006.50","DOIUrl":"https://doi.org/10.1109/ICDE.2006.50","url":null,"abstract":"We study the problem of continuous relational query processing in Internet-scale overlay networks realized by distributed hash tables. We concentrate on the case of continuous two-way equi-join queries. Joins are hard to evaluate in a distributed continuous query environment because data from more than one relations is needed, and this data is inserted in the network asynchronously. Each time a new tuple is inserted, the network nodes have to cooperate to check if this tuple can contribute to the satisfaction of a query when combined with previously inserted tuples. We propose a series of algorithms that initially index queries at network nodes using hashing. Then, they exploit the values of join attributes in incoming tuples to rewrite the given queries into simpler ones, and reindex them in the network where they might be satisfied by existing or future tuples. We present a detailed experimental evaluation in a simulated environment and we show that our algorithms are scalable, balance the storage and query processing load and keep the network traffic low.","PeriodicalId":6819,"journal":{"name":"22nd International Conference on Data Engineering (ICDE'06)","volume":"83 1","pages":"43-43"},"PeriodicalIF":0.0,"publicationDate":"2006-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80971232","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}
As XQuery nears standardization, more sophisticated XQuery applications are emerging, which often exploit the entire language and are applied to non-trivial XML sources. We propose an algebra and optimization techniques that are suitable for building an XQuery compiler that is complete, correct, and efficient. We describe the compilation rules for the complete language into that algebra and present novel optimization techniques that address the needs of complex queries. These techniques include new query unnesting rewritings and specialized join algorithms that account for XQuery’s complex predicate semantics. The algebra and optimizations are implemented in the Galax XQuery engine, and yield execution plans that are up to three orders of magnitude faster than earlier versions of Galax.
{"title":"A Complete and Efficient Algebraic Compiler for XQuery","authors":"C. Ré, Jérôme Siméon, M. Fernández","doi":"10.1109/ICDE.2006.6","DOIUrl":"https://doi.org/10.1109/ICDE.2006.6","url":null,"abstract":"As XQuery nears standardization, more sophisticated XQuery applications are emerging, which often exploit the entire language and are applied to non-trivial XML sources. We propose an algebra and optimization techniques that are suitable for building an XQuery compiler that is complete, correct, and efficient. We describe the compilation rules for the complete language into that algebra and present novel optimization techniques that address the needs of complex queries. These techniques include new query unnesting rewritings and specialized join algorithms that account for XQuery’s complex predicate semantics. The algebra and optimizations are implemented in the Galax XQuery engine, and yield execution plans that are up to three orders of magnitude faster than earlier versions of Galax.","PeriodicalId":6819,"journal":{"name":"22nd International Conference on Data Engineering (ICDE'06)","volume":"37 1","pages":"14-14"},"PeriodicalIF":0.0,"publicationDate":"2006-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81041928","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 top-k query combines different rankings of the same set of objects and returns the k objects with the highest combined score according to an aggregate function. We bring to light some key observations, which impose two phases that any top-k algorithm, based on sorted accesses, should go through. Based on them, we propose a new algorithm, which is designed to minimize the number of object accesses, the computational cost, and the memory requirements of top-k search. Adaptations of our algorithm for search variants (exact scores, on-line and incremental search, top-k joins, other aggregate functions, etc.) are also provided. Extensive experiments with synthetic and real data show that, compared to previous techniques, our method accesses fewer objects, while being orders of magnitude faster.
{"title":"Efficient Aggregation of Ranked Inputs","authors":"N. Mamoulis, K. Cheng, Man Lung Yiu, D. Cheung","doi":"10.1109/ICDE.2006.54","DOIUrl":"https://doi.org/10.1109/ICDE.2006.54","url":null,"abstract":"A top-k query combines different rankings of the same set of objects and returns the k objects with the highest combined score according to an aggregate function. We bring to light some key observations, which impose two phases that any top-k algorithm, based on sorted accesses, should go through. Based on them, we propose a new algorithm, which is designed to minimize the number of object accesses, the computational cost, and the memory requirements of top-k search. Adaptations of our algorithm for search variants (exact scores, on-line and incremental search, top-k joins, other aggregate functions, etc.) are also provided. Extensive experiments with synthetic and real data show that, compared to previous techniques, our method accesses fewer objects, while being orders of magnitude faster.","PeriodicalId":6819,"journal":{"name":"22nd International Conference on Data Engineering (ICDE'06)","volume":"1 1","pages":"72-72"},"PeriodicalIF":0.0,"publicationDate":"2006-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87378768","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}
D. Lomet, R. Barga, M. Mokbel, German Shegalov, Rui Wang, Yunyue Zhu
Transaction time databases retain and provide access to prior states of a database. An update "inserts" a new record while preserving the old version. Immortal DB builds transaction time database support into a database engine, not in middleware. It supports as of queries returning records current at the specified time. It also supports snapshot isolation concurrency control. Versions are stamped with the "clock times" of their updating transactions. The timestamp order agrees with transaction serialization order. Lazy timestamping propagates timestamps to transaction updates after commit. Versions are kept in an integrated storage structure, with historical versions initially stored with current data. Time-splits of pages permit large histories to be maintained, and enable time based indexing, which is essential for high performance historical queries. Experiments show that Immortal DB introduces little overhead for accessing recent database states while providing access to past states.
{"title":"Transaction Time Support Inside a Database Engine","authors":"D. Lomet, R. Barga, M. Mokbel, German Shegalov, Rui Wang, Yunyue Zhu","doi":"10.1109/ICDE.2006.162","DOIUrl":"https://doi.org/10.1109/ICDE.2006.162","url":null,"abstract":"Transaction time databases retain and provide access to prior states of a database. An update \"inserts\" a new record while preserving the old version. Immortal DB builds transaction time database support into a database engine, not in middleware. It supports as of queries returning records current at the specified time. It also supports snapshot isolation concurrency control. Versions are stamped with the \"clock times\" of their updating transactions. The timestamp order agrees with transaction serialization order. Lazy timestamping propagates timestamps to transaction updates after commit. Versions are kept in an integrated storage structure, with historical versions initially stored with current data. Time-splits of pages permit large histories to be maintained, and enable time based indexing, which is essential for high performance historical queries. Experiments show that Immortal DB introduces little overhead for accessing recent database states while providing access to past states.","PeriodicalId":6819,"journal":{"name":"22nd International Conference on Data Engineering (ICDE'06)","volume":"42 1","pages":"35-35"},"PeriodicalIF":0.0,"publicationDate":"2006-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80599929","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 introduces the use of wavelets for information retrieval in a peer-to-peer environment. In order to achieve our purposes, we use a new combination between broadcasting and a hierarchical overlay. Compared to previous approaches, we do not store complete information about the children of a super-peer, nor do we broadcast the queries blindly. We approximate the feature vectors using the multiresolution analysis and the discrete wavelet transform. Each peer is represented by a high-dimensional feature vector and the height of the hierarchy is logarithmic in the dimensionality of this feature vector. Leaf nodes represent real peers, while internal nodes are virtual peers used for routing. Our retrieval method has been tested with both real and synthetic data and shown to be efficient in retrieving relevant information, resulting in good precision and recall on four standard test collections.
{"title":"HiWaRPP ― Hierarchical Wavelet-based Retrieval on Peer-to-Peer Network","authors":"M. Lupu, Bei Yu","doi":"10.1109/ICDE.2006.76","DOIUrl":"https://doi.org/10.1109/ICDE.2006.76","url":null,"abstract":"This paper introduces the use of wavelets for information retrieval in a peer-to-peer environment. In order to achieve our purposes, we use a new combination between broadcasting and a hierarchical overlay. Compared to previous approaches, we do not store complete information about the children of a super-peer, nor do we broadcast the queries blindly. We approximate the feature vectors using the multiresolution analysis and the discrete wavelet transform. Each peer is represented by a high-dimensional feature vector and the height of the hierarchy is logarithmic in the dimensionality of this feature vector. Leaf nodes represent real peers, while internal nodes are virtual peers used for routing. Our retrieval method has been tested with both real and synthetic data and shown to be efficient in retrieving relevant information, resulting in good precision and recall on four standard test collections.","PeriodicalId":6819,"journal":{"name":"22nd International Conference on Data Engineering (ICDE'06)","volume":"31 1","pages":"133-133"},"PeriodicalIF":0.0,"publicationDate":"2006-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80652434","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}
Most previously proposed frequent graph mining algorithms are intended to find the complete set of all frequent, closed subgraphs. However, in many cases only a subset of the frequent subgraphs with a certain topology is of special interest. Thus, the method of mining the complete set of all frequent subgraphs is not suitable for mining these frequent subgraphs of special interest as it wastes considerable computing power and space on uninteresting subgraphs. In this paper we develop a new algorithm, CLAN, to mine the frequent closed cliques, the most coherent structures in the graph setting. By exploring some properties of the clique pattern, we can simplify the canonical label design and the corresponding clique (or subclique) isomorphism testing. Several effective pruning methods are proposed to prune the search space, while the clique closure checking scheme is used to remove the non-closed clique patterns. Our empirical results show that CLAN is very efficient for large dense graph databases with which the traditional graph mining algorithms fail. The novelty of our method is further demonstrated by the application of CLAN in mining highly correlated stocks from large stock market data.
{"title":"CLAN: An Algorithm for Mining Closed Cliques from Large Dense Graph Databases","authors":"Jianyong Wang, Zhiping Zeng, Lizhu Zhou","doi":"10.1109/ICDE.2006.34","DOIUrl":"https://doi.org/10.1109/ICDE.2006.34","url":null,"abstract":"Most previously proposed frequent graph mining algorithms are intended to find the complete set of all frequent, closed subgraphs. However, in many cases only a subset of the frequent subgraphs with a certain topology is of special interest. Thus, the method of mining the complete set of all frequent subgraphs is not suitable for mining these frequent subgraphs of special interest as it wastes considerable computing power and space on uninteresting subgraphs. In this paper we develop a new algorithm, CLAN, to mine the frequent closed cliques, the most coherent structures in the graph setting. By exploring some properties of the clique pattern, we can simplify the canonical label design and the corresponding clique (or subclique) isomorphism testing. Several effective pruning methods are proposed to prune the search space, while the clique closure checking scheme is used to remove the non-closed clique patterns. Our empirical results show that CLAN is very efficient for large dense graph databases with which the traditional graph mining algorithms fail. The novelty of our method is further demonstrated by the application of CLAN in mining highly correlated stocks from large stock market data.","PeriodicalId":6819,"journal":{"name":"22nd International Conference on Data Engineering (ICDE'06)","volume":"136 1","pages":"73-73"},"PeriodicalIF":0.0,"publicationDate":"2006-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79670997","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}
Sunil Jigyasu, Sujeet Banerjee, V. Borkar, M. Carey, Kanad Dixit, Anil Malkani, S. Thatte
SQL has long been the standard language for retrieving and manipulating data in relational database systems. XML has become the standard format for data exchange, and XQuery is on its way to becoming the standard language for querying XML data. The BEA AquaLogic Data Services Platform provides a service-oriented, XML-based view of heterogeneous enterprise data sources and allows this view to be queried using XQuery. AquaLogic DSP includes a JDBC driver that connects the old (SQL) world with the new (XML) world via a SQL-to-XQuery translator. This paper outlines the issues related to creating such a driver and details the approach used to translate SQL queries into XQuery expressions. The paper also touches on performance considerations related to handling XML query results in a context where JDBC result sets are the desired output format.
{"title":"SQL to XQuery Translation in the AquaLogic Data Services Platform","authors":"Sunil Jigyasu, Sujeet Banerjee, V. Borkar, M. Carey, Kanad Dixit, Anil Malkani, S. Thatte","doi":"10.1109/ICDE.2006.147","DOIUrl":"https://doi.org/10.1109/ICDE.2006.147","url":null,"abstract":"SQL has long been the standard language for retrieving and manipulating data in relational database systems. XML has become the standard format for data exchange, and XQuery is on its way to becoming the standard language for querying XML data. The BEA AquaLogic Data Services Platform provides a service-oriented, XML-based view of heterogeneous enterprise data sources and allows this view to be queried using XQuery. AquaLogic DSP includes a JDBC driver that connects the old (SQL) world with the new (XML) world via a SQL-to-XQuery translator. This paper outlines the issues related to creating such a driver and details the approach used to translate SQL queries into XQuery expressions. The paper also touches on performance considerations related to handling XML query results in a context where JDBC result sets are the desired output format.","PeriodicalId":6819,"journal":{"name":"22nd International Conference on Data Engineering (ICDE'06)","volume":"17 1","pages":"97-97"},"PeriodicalIF":0.0,"publicationDate":"2006-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89539748","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}
Eduard Constantin Dragut, Wensheng Wu, A. Sistla, Clement T. Yu, W. Meng
Recently, there are many e-commerce search engines that return information from Web databases. Unlike text search engines, these e-commerce search engines have more complicated user interfaces. Our aim is to construct automatically a natural query user interface that integrates a set of interfaces over a given domain of interest. For example, each airline company has a query interface for ticket reservation and our system can construct an integrated interface for all these companies. This will permit users to access information uniformly from multiple sources. Each query interface from an e-commerce search engine is designed so as to facilitate users to provide necessary information. Specifically, (1) related pieces of information such as first name and last name are grouped together and (2) certain hierarchical relationships are maintained. In this paper, we provide an algorithm to compute an integrated interface from query interfaces of the same domain. The integrated query interface can be proved to preserve the above two types of relationships. Experiments on five domains verify our theoretical study.
{"title":"Merging Source Query Interfaces onWeb Databases","authors":"Eduard Constantin Dragut, Wensheng Wu, A. Sistla, Clement T. Yu, W. Meng","doi":"10.1109/ICDE.2006.91","DOIUrl":"https://doi.org/10.1109/ICDE.2006.91","url":null,"abstract":"Recently, there are many e-commerce search engines that return information from Web databases. Unlike text search engines, these e-commerce search engines have more complicated user interfaces. Our aim is to construct automatically a natural query user interface that integrates a set of interfaces over a given domain of interest. For example, each airline company has a query interface for ticket reservation and our system can construct an integrated interface for all these companies. This will permit users to access information uniformly from multiple sources. Each query interface from an e-commerce search engine is designed so as to facilitate users to provide necessary information. Specifically, (1) related pieces of information such as first name and last name are grouped together and (2) certain hierarchical relationships are maintained. In this paper, we provide an algorithm to compute an integrated interface from query interfaces of the same domain. The integrated query interface can be proved to preserve the above two types of relationships. Experiments on five domains verify our theoretical study.","PeriodicalId":6819,"journal":{"name":"22nd International Conference on Data Engineering (ICDE'06)","volume":"1 1","pages":"46-46"},"PeriodicalIF":0.0,"publicationDate":"2006-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89757099","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}
Bianca Schroeder, Mor Harchol-Balter, A. Iyengar, E. Nahum
Transaction processing systems lie at the core of modern e-commerce applications such as on-line retail stores, banks and airline reservation systems. The economic success of these applications depends on the ability to achieve high user satisfaction, since a single mouse-click is all that it takes a frustrated user to switch to a competitor. Given that system resources are limited and demands are varying, it is difficult to provide optimal performance to all users at all times. However, often transactions can be divided into different classes based on how important they are to the online retailer. For example, transactions initiated by a "big spending" client are more important than transactions from a client that only browses the site. A natural goal then is to ensure short delays for the class of important transactions, while for the less important transactions longer delays are acceptable.
{"title":"Achieving Class-Based QoS for Transactional Workloads","authors":"Bianca Schroeder, Mor Harchol-Balter, A. Iyengar, E. Nahum","doi":"10.1109/ICDE.2006.11","DOIUrl":"https://doi.org/10.1109/ICDE.2006.11","url":null,"abstract":"Transaction processing systems lie at the core of modern e-commerce applications such as on-line retail stores, banks and airline reservation systems. The economic success of these applications depends on the ability to achieve high user satisfaction, since a single mouse-click is all that it takes a frustrated user to switch to a competitor. Given that system resources are limited and demands are varying, it is difficult to provide optimal performance to all users at all times. However, often transactions can be divided into different classes based on how important they are to the online retailer. For example, transactions initiated by a \"big spending\" client are more important than transactions from a client that only browses the site. A natural goal then is to ensure short delays for the class of important transactions, while for the less important transactions longer delays are acceptable.","PeriodicalId":6819,"journal":{"name":"22nd International Conference on Data Engineering (ICDE'06)","volume":"107 1","pages":"153-153"},"PeriodicalIF":0.0,"publicationDate":"2006-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76712329","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}
In this paper, we propose DBSampler, a query execution mechanism to answer "partial selection" queries in peerto- peer databases. A partial selection query is an arbitrary selection query that is satisfied with a fraction in of the results; a universal operation with applications in database tuning, query optimization and approximate query processing in peer-to-peer databases. DBSampler is based on an epidemic dissemination algorithm. We model the epidemic dissemination as a percolation problem and by rigorous percolation analysis tune DBSampler per-query and on-thefly to answer partial queries correctly and efficiently. We verify the efficiency of DBSampler in terms of query cost and query time via extensive simulation.
{"title":"Partial Selection Query in Peer-to-Peer Databases","authors":"F. Kashani, C. Shahabi","doi":"10.1109/ICDE.2006.111","DOIUrl":"https://doi.org/10.1109/ICDE.2006.111","url":null,"abstract":"In this paper, we propose DBSampler, a query execution mechanism to answer \"partial selection\" queries in peerto- peer databases. A partial selection query is an arbitrary selection query that is satisfied with a fraction in of the results; a universal operation with applications in database tuning, query optimization and approximate query processing in peer-to-peer databases. DBSampler is based on an epidemic dissemination algorithm. We model the epidemic dissemination as a percolation problem and by rigorous percolation analysis tune DBSampler per-query and on-thefly to answer partial queries correctly and efficiently. We verify the efficiency of DBSampler in terms of query cost and query time via extensive simulation.","PeriodicalId":6819,"journal":{"name":"22nd International Conference on Data Engineering (ICDE'06)","volume":"38 1","pages":"132-132"},"PeriodicalIF":0.0,"publicationDate":"2006-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76725423","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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