Filters








742 Hits in 6.6 sec

Cost-based optimization of aggregation star queries on hierarchically clustered data warehouses

Aris Tsois, Nikos Karayannidis, Timos K. Sellis, Dimitri Theodoratos
2002 Design and Management of Data Warehouses  
A methodology recently proposed to improve processing of star queries on data warehouses is the clustering and indexing of fact tables using their multidimensional hierarchies [DRSN98, MRB99, KS01].  ...  Due to this improved organization schema, processing of aggregation star queries changes dramatically creating new optimization opportunities.  ...  Figure 2: The template for aggregation star queries In Figure 1 , we depict an example of a hierarchically clustered star schema for a simplified data warehouse consisting of four dimensions: CUSTOMER  ... 
dblp:conf/dmdw/TsoisKST02 fatcat:avfxnetmfrhzzfiubf7dpjjs7y

Processing Star Queries on Hierarchically-Clustered Fact Tables [chapter]

Nikos Karayannidis, Aris Tsois, Timos Sellis, Roland Pieringer, Volker Markl, Frank Ramsak, Robert Fenk, Klaus Elhardt, Rudolf Bayer
2002 VLDB '02: Proceedings of the 28th International Conference on Very Large Databases  
To this end, a new class of fact table organizations has emerged that exploits path-based surrogate keys in order to hierarchically cluster the fact table data of a star schema [DRSN98, MRB99, KS01].  ...  Star queries are the most prevalent kind of queries in data warehousing, OLAP and business intelligence applications. Thus, there is an imperative need for efficiently processing star queries.  ...  This physical clustering results in a reduced I/O cost for the majority of star queries, which are based on the dimension hierarchies.  ... 
doi:10.1016/b978-155860869-6/50070-6 dblp:conf/vldb/KarayannidisTSPMRFEB02 fatcat:uv7s77uizrat3ecxeijpayd53u

WARLOCK: A Data Allocation Tool for Parallel Warehouses

Thomas Stöhr, Erhard Rahm
2001 Very Large Data Bases Conference  
The considered workload consists of a variety of multi-dimensional join and aggregation (star) queries on the fact tables that refer to dimension attributes.  ...  It supports multi-dimensional fragmentations and can deal with data skew for parallel data warehouses based on a Shared Everything or Shared Disk architecture.  ... 
dblp:conf/vldb/StohrR01 fatcat:zipdjvengnhkpeuuqzvymxecfy

Warehousing complex data from the Web [article]

Omar Boussaid , Sabine Loudcher
2017 arXiv   pre-print
We also address the crucial issue of performance in XML warehouses.  ...  Our approach includes the integration of complex data in an ODS, under the form of XML documents; their dimensional modeling and storage in an XML data warehouse; and their analysis with combined OLAP  ...  Hence, it is crucial to devise means of optimizing the performance of XML data warehouses.  ... 
arXiv:1701.00398v1 fatcat:64yhgypd4fdlrhy7gwobtljs7y

From enterprise models to dimensional models: a methodology for data warehouse and data mart design

Daniel L. Moody, Mark A. R. Kortink
2000 Design and Management of Data Warehouses  
This can be used to design data warehouses and data marts based on enterprise data models. The first step of the method involves classifying entities in the data model into a number of categories.  ...  A number of design alternatives are presented, including a flat schema, a terraced schema, a star schema and a snowflake schema. We also define a new type of schema called a star cluster schema.  ...  Star Schema Design Approach Kimball's design method is a "first principles" approach, which is based on analysis of user query requirements.  ... 
dblp:conf/dmdw/MoodyK00 fatcat:u2ycsffcf5csfpx2gmb3mkpqhm

An Association Rule Mining for Materialized View Selection and View Maintanance

P. R.Vishwanath, Rajyalakshmi Rajyalakshmi, Sridhar Reddy
2015 International Journal of Computer Applications  
Data warehouse (DW) is a repository with query interface in support of Decision support systems.  ...  This paper proposed frequent rule mining on of the Data mining approach for the selection and maintenance of MV"S.  ...  To implement Data warehouse, one of the model proposed is Multi Dimensional Data model (MDM). 3.5 Kamel Aouiche et al [5] proposed Clustering based materialized selection using the clustering, one of  ... 
doi:10.5120/19184-0670 fatcat:7ud7umasmbgs7cl42d4t2rxqru

X-WACoDa: An XML-based approach for Warehousing and Analyzing Complex Data [article]

Hadj Mahboubi, Sabine Loudcher, Jérôme Darmont
2017 arXiv   pre-print
We also present a software platform that is based on this model, as well as a case study that illustrates its usage.  ...  Unfortunately, no standard XML data warehouse architecture emerges.  ...  Finally, Ben Messaoud et al. (2006a) propose an OLAP aggregation operator that is based on an automatic clustering method: OpAC.  ... 
arXiv:1701.08033v1 fatcat:dfuzbfzhizhapnp5kuqxtujq6e

An Architecture for Integrated Online Analytical Mining

Muhammad Usman, Sohail Asghar
2011 Journal of Emerging Technologies in Web Intelligence  
In the proposed work, hierarchical clustering has been used as the data mining technique and three types of schemas namely star, snowflake and galaxy were automatically generated.  ...  Validation has been done by performing experiments on real life data set.  ...  [33] , proposed cost based optimization of aggregation star queries on hierarchically clustered data warehouses.  ... 
doi:10.4304/jetwi.3.2.74-99 fatcat:ppkarvwrojho5ftwdwqqok2m6m

Multi-Dimensional Database Allocation for Parallel Data Warehouses

Thomas Stöhr, Holger Märtens, Erhard Rahm
2000 Very Large Data Bases Conference  
In this study, we consider the allocation of relational data warehouses based on a star schema and utilizing bitmap index structures.  ...  We investigate how a multi-dimensional hierarchical data fragmentation of the fact table supports queries referencing different subsets of the schema dimensions.  ...  We focus on relational data warehouses based on a star schema [5] . The database thus consists of a huge fact table and multiple dimension tables.  ... 
dblp:conf/vldb/StohrMR00 fatcat:t7phux3nencjldbe4rcwbaaoeu

Minimizing the MOLAP/ROLAP Divide: You Can Have Your Performance and Scale It Too

Todd Eavis, Ahmad Taleb
2013 Journal of Computing Science and Engineering  
Typically, OLAP servers are implemented on top of either proprietary array-based storage engines (MOLAP) or as extensions to conventional relational DBMSs (ROLAP).  ...  Based upon a combination of R-trees and bitmap indexes, the storage engine has been integrated with a robust OLAP query engine prototype that is able to fully exploit the efficiency of the proposed storage  ...  Recently, column store databases have been investigated as a means to minimize IO costs on aggregation queries [8] .  ... 
doi:10.5626/jcse.2013.7.1.1 fatcat:26pyagf7wzcdfox2rlbpxlacsy

Handling Large Workloads by Profiling and Clustering [chapter]

Matteo Golfarelli
2003 Lecture Notes in Computer Science  
View materialization is recognized to be one of the most effective ways to increase the Data Warehouse performance; nevertheless, due to the computational complexity of the techniques aimed at choosing  ...  In this paper we propose a set of statistical indicators that can be used by the designer to characterize the workload of the Data Warehouse, thus driving the logical and physical optimization tasks; furthermore  ...  Introduction During the design of a data warehouse (DW), the phases aimed at improving the system performance are mainly the logical and physical ones.  ... 
doi:10.1007/978-3-540-45228-7_22 fatcat:gu6u37avrrcxrhfaonxpbro3au

Integration of Data Mining and Data Warehousing: A Practical Methodology

Muhammad Usman, Russel Pears
2010 International Journal of Advancements in Computing Technology  
Traditional data mining techniques such as clustering clusters only the numeric data.  ...  visual data exploration, automatic warehouse schema generation and integration of data mining and warehousing.  ...  The authors in [19] , focused on the hierarchical clustering of mixed data based on distance hierarchy.  ... 
doi:10.4156/ijact.vol2.issue3.4 fatcat:jsmrrhak3vhefl2psd6wewstta

Data mining-based fragmentation of XML data warehouses

Hadj Mahboubi, Jérôme Darmont
2008 Proceeding of the ACM 11th international workshop on Data warehousing and OLAP - DOLAP '08  
With the multiplication of XML data sources, many XML data warehouse models have been proposed to handle data heterogeneity and complexity in a way relational data warehouses fail to achieve.  ...  In this paper, we propose the use of a k-means-based fragmentation approach that allows to master the number of fragments through its k parameter.  ...  Predicate Clustering Our objective is to derive fragments that optimize data access for a given set of queries.  ... 
doi:10.1145/1458432.1458435 dblp:conf/dolap/MahboubiD08 fatcat:zeypfx4hq5c5nis3sh44tf6oem

Exploiting hierarchical clustering in evaluating multidimensional aggregation queries

Dimitri Theodoratos
2003 Proceedings of the 6th ACM international workshop on Data warehousing and OLAP - DOLAP '03  
Recently, a multidimensional hierarchical clustering schema for star schemas is suggested.  ...  Multidimensional aggregation queries constitute the single most important class of queries for data warehousing applications and decision support systems.  ...  The query optimizer should also decide, based on a cost model and statistical information, about the order of joining the (restricted) dimension tables with the tuples derived from the fact table as this  ... 
doi:10.1145/956060.956072 dblp:conf/dolap/Theodoratos03 fatcat:wypq7l6uqbbbzn3oduyxc5xl6i

Exploiting hierarchical clustering in evaluating multidimensional aggregation queries

Dimitri Theodoratos
2003 Proceedings of the 6th ACM international workshop on Data warehousing and OLAP - DOLAP '03  
Recently, a multidimensional hierarchical clustering schema for star schemas is suggested.  ...  Multidimensional aggregation queries constitute the single most important class of queries for data warehousing applications and decision support systems.  ...  The query optimizer should also decide, based on a cost model and statistical information, about the order of joining the (restricted) dimension tables with the tuples derived from the fact table as this  ... 
doi:10.1145/956069.956072 fatcat:dwsnxer2cfh4ral5rj7ijwrpjm
« Previous Showing results 1 — 15 out of 742 results