The Experts below are selected from a list of 12501 Experts worldwide ranked by ideXlab platform
Walid G Aref - One of the best experts on this subject based on the ideXlab platform.
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hippocratic Postgresql
International Conference on Data Engineering, 2009Co-Authors: Jalaja Padma, Yasin N Silva, Muhammad Arshad, Walid G ArefAbstract:Privacy preservation has become an important requirement in information systems that deal with personal data. In many cases this requirement is imposed by laws that recognize the right of data owners to control whom their information is shared with and the purposes for which it can be shared. Hippocratic databases have been proposed as an answer to this privacy requirement; they extend the architecture of standard DBMSs with components that ensure personal data is handled in compliance with its associated privacy definitions. Previous work in Hippocratic databases has proposed the design of some of these components. Unfortunately, there has not been much work done to implement these components as an integral part of a DBMS and study the problems faced to realize the Hippocratic databases. The main goal of the 'Hippocratic Postgresql' project is to perform this implementation and study. The project includes the implementation of components to support limited disclosure, limited retention time, and management of multiple policies and policy versions. This demo presents the use of these components both from a terminal-based SQL command interface and through a Web-based healthcare application that makes use of the implemented database-level privacy features. Hippocratic Postgresql has the novel feature of augmenting both k-anonymity and generalization hierarchies into the Hippocratic DBMS engine functionality. Several interesting problems emerge as a result and their solutions are presented in the context of this demo.
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space partitioning trees in Postgresql realization and performance
International Conference on Data Engineering, 2006Co-Authors: Mohamed Y. Eltabakh, Ramy Eltarras, Walid G ArefAbstract:Many evolving database applications warrant the use of non-traditional indexing mechanisms beyond B+-trees and hash tables. SP-GiST is an extensible indexing framework that broadens the class of supported indexes to include disk-based versions of a wide variety of space-partitioning trees, e.g., disk-based trie variants, quadtree variants, and kd-trees. This paper presents a serious attempt at implementing and realizing SP-GiST-based indexes inside Postgresql. Several index types are realized inside Postgresql facilitated by rapid SP-GiST instantiations. Challenges, experiences, and performance issues are addressed in the paper. Performance comparisons are conducted from within Postgresql to compare update and search performances of SP-GiST-based indexes against the B+-tree and the R-tree for string, point, and line segment data sets. Interesting results that highlight the potential performance gains of SPGiST- based indexes are presented in the paper.
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ICDE - Space-Partitioning Trees in Postgresql: Realization and Performance
22nd International Conference on Data Engineering (ICDE'06), 2006Co-Authors: Mohamed Y. Eltabakh, Ramy Eltarras, Walid G ArefAbstract:Many evolving database applications warrant the use of non-traditional indexing mechanisms beyond B+-trees and hash tables. SP-GiST is an extensible indexing framework that broadens the class of supported indexes to include disk-based versions of a wide variety of space-partitioning trees, e.g., disk-based trie variants, quadtree variants, and kd-trees. This paper presents a serious attempt at implementing and realizing SP-GiST-based indexes inside Postgresql. Several index types are realized inside Postgresql facilitated by rapid SP-GiST instantiations. Challenges, experiences, and performance issues are addressed in the paper. Performance comparisons are conducted from within Postgresql to compare update and search performances of SP-GiST-based indexes against the B+-tree and the R-tree for string, point, and line segment data sets. Interesting results that highlight the potential performance gains of SPGiST- based indexes are presented in the paper.
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To Trie or Not to Trie? Realizing Space-partitioning Trees inside Postgresql: Challenges, Experiences and Performance
2005Co-Authors: Mohamed Y. Eltabakh, Ramy Eltarras, Walid G ArefAbstract:l'l1an~' evolving datil bilse applications warrant the use of non-twditional indexing mechanisms beyond B+-trees and hash tables. SPGiST is an extensible indexing framework that broadens the class of supported indexes to include disk-based wrsions of a \vide variety of space-partitioning trees, e.g., disk-based trie variants, quadtree vilriants, and kd-trees. This paper presents il serious attempt at implementing and realizing SP-GiST-based indexes inside Postgresql. Several index types are realized inside Postgresql facilitated by rapid SP-GiST instantiations. Challenge~, experiences. and performance issues are addressed in the paper. Performance comparisons are conducted from within Postgresql to compare updilte ilnd search performances of SP-GiST-based indexes against the B+-tree and the R-tree for text string and point data sets. Interesting performilnce results are presented in the paper. Results highlight the potentifd performance gains of SP-GiST-based indexes as well ilS several strengths and weaknesses of SP-GiST-bilsed indexes that need to be addressed in future research
Liu Chang - One of the best experts on this subject based on the ideXlab platform.
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research on the mechanism of query optimization in the Postgresql
Computer Science, 2005Co-Authors: Liu ChangAbstract:As the most powerful and complex free DBMS with the most features, Postgresql not only draws the DBMS researchers' developers' attention, but also is adopted in commerce more and more. It seems that it has a very promising future. This article discusses the implementation of the Query Optimization of the Postgresql, and analyzes the kernel part of the optimizer, the generating and choosing of the execution path. And, it points out a shortage of the optimization arithmetic.
Elisa Bertino - One of the best experts on this subject based on the ideXlab platform.
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Postgresql anomaly detector
Annual Information Security Symposium, 2013Co-Authors: Bilal Shebaro, Asmaa Sallam, Ashish Karma, Elisa BertinoAbstract:We propose to demonstrate the design, implementation, and the capabilities of an anomaly detection (AD) system integrated with a relational database management system (DBMS). Our AD system is trained by extracting relevant features from the parse-tree representation of the SQL commands, and then uses the DBMS roles as the classes for the bayesian classifier. In the detection phase, the maximum apriori probability role is chosen by the classifier which, if not matching the role associated with the SQL command, raises an alarm. We have implemented such system in the Postgresql DBMS, integrated with the statistics collection and the query processing mechanism of the DBMS. During the demonstration, our audience will be given the choice of training our system using either synthetic role-based SQL query traces based on probability sampling, or by entering their own set of training queries. In the subsequent detection mode, the audience can test the detection capabilities of the system by submitting arbitrary SQL commands. We will also allow the audience to generate arbitrary workloads to measure the overhead of the training phase and the detection phase of our AD mechanism on the performance of the DBMS.
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Postgresql anomalous query detector
Extending Database Technology, 2013Co-Authors: Bilal Shebaro, Asmaa Sallam, Ashish Kamra, Elisa BertinoAbstract:We propose to demonstrate the design, implementation, and the capabilities of an anomaly detection (AD) system integrated with a relational database management system (DBMS). Our AD system is trained by extracting relevant features from the parse-tree representation of the SQL commands, and then uses the DBMS roles as the classes for the bayesian classifier. In the detection phase, the maximum apriori probability role is chosen by the classifier which, if not matching the role associated with the SQL command, raises an alarm. We have implemented such system in the Postgresql DBMS, integrated with the statistics collection and the query processing mechanism of the DBMS. During the demonstration, our audience will be given the choice of training our system using either synthetic role-based SQL query traces based on probability sampling, or by entering their own set of training queries. In the subsequent detection mode, the audience can test the detection capabilities of the system by submitting arbitrary SQL commands. We will also allow the audience to generate arbitrary work loads to measure the overhead of the training phase and the detection phase of our AD mechanism on the performance of the DBMS.
Mohamed Y. Eltabakh - One of the best experts on this subject based on the ideXlab platform.
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space partitioning trees in Postgresql realization and performance
International Conference on Data Engineering, 2006Co-Authors: Mohamed Y. Eltabakh, Ramy Eltarras, Walid G ArefAbstract:Many evolving database applications warrant the use of non-traditional indexing mechanisms beyond B+-trees and hash tables. SP-GiST is an extensible indexing framework that broadens the class of supported indexes to include disk-based versions of a wide variety of space-partitioning trees, e.g., disk-based trie variants, quadtree variants, and kd-trees. This paper presents a serious attempt at implementing and realizing SP-GiST-based indexes inside Postgresql. Several index types are realized inside Postgresql facilitated by rapid SP-GiST instantiations. Challenges, experiences, and performance issues are addressed in the paper. Performance comparisons are conducted from within Postgresql to compare update and search performances of SP-GiST-based indexes against the B+-tree and the R-tree for string, point, and line segment data sets. Interesting results that highlight the potential performance gains of SPGiST- based indexes are presented in the paper.
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ICDE - Space-Partitioning Trees in Postgresql: Realization and Performance
22nd International Conference on Data Engineering (ICDE'06), 2006Co-Authors: Mohamed Y. Eltabakh, Ramy Eltarras, Walid G ArefAbstract:Many evolving database applications warrant the use of non-traditional indexing mechanisms beyond B+-trees and hash tables. SP-GiST is an extensible indexing framework that broadens the class of supported indexes to include disk-based versions of a wide variety of space-partitioning trees, e.g., disk-based trie variants, quadtree variants, and kd-trees. This paper presents a serious attempt at implementing and realizing SP-GiST-based indexes inside Postgresql. Several index types are realized inside Postgresql facilitated by rapid SP-GiST instantiations. Challenges, experiences, and performance issues are addressed in the paper. Performance comparisons are conducted from within Postgresql to compare update and search performances of SP-GiST-based indexes against the B+-tree and the R-tree for string, point, and line segment data sets. Interesting results that highlight the potential performance gains of SPGiST- based indexes are presented in the paper.
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To Trie or Not to Trie? Realizing Space-partitioning Trees inside Postgresql: Challenges, Experiences and Performance
2005Co-Authors: Mohamed Y. Eltabakh, Ramy Eltarras, Walid G ArefAbstract:l'l1an~' evolving datil bilse applications warrant the use of non-twditional indexing mechanisms beyond B+-trees and hash tables. SPGiST is an extensible indexing framework that broadens the class of supported indexes to include disk-based wrsions of a \vide variety of space-partitioning trees, e.g., disk-based trie variants, quadtree vilriants, and kd-trees. This paper presents il serious attempt at implementing and realizing SP-GiST-based indexes inside Postgresql. Several index types are realized inside Postgresql facilitated by rapid SP-GiST instantiations. Challenge~, experiences. and performance issues are addressed in the paper. Performance comparisons are conducted from within Postgresql to compare updilte ilnd search performances of SP-GiST-based indexes against the B+-tree and the R-tree for text string and point data sets. Interesting performilnce results are presented in the paper. Results highlight the potentifd performance gains of SP-GiST-based indexes as well ilS several strengths and weaknesses of SP-GiST-bilsed indexes that need to be addressed in future research
Sangwon Lee - One of the best experts on this subject based on the ideXlab platform.
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iplization of Postgresql on nvdimm
International Conference on e-Education e-Business e-Management and e-Learning, 2018Co-Authors: Joobo Shim, Sangwon LeeAbstract:A novel approach to DBMS design called In-Page Logging (IPL) was proposed a decade ago. The IPL system exploits characteristic of flash memory; asymmetric write/read speed. This approach manages per page log in erase unit of flash memory and avoids page write but saves redo log. When the page is required merge operation, which is instant recovery process, generates updated version of page using old page and its redo log. In fact this never has been implemented to real DBMS system since lack of fast, persistent, byte-addressable, and affordable device. Since NVDIMM matches with concept of IPL, we implemented IPL to Postgresql, a commercial open source DBMS, employing it as IPL log device. The experiment showed improvement of reducing write amount, which leads to performance gain and SSD lifetime increase.
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flash aware index scan in Postgresql
International Conference on Data Engineering, 2015Co-Authors: Dasom Hwang, Woonhak Kang, Sangwon LeeAbstract:Recently, the trend of storage markets has changed from HDDs that have dominated the markets for the last several decades to flash based SSDs. Corresponding to the drift, various studies have been conducted to adapt traditional DBMS to SSD based storage devices. However, most DBMSs are still more HDD-friendly.