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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  
In this paper, we present a complete abstract processing plan that captures all the necessary steps in evaluating such queries over hierarchically clustered fact tables.  ...  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].  ...  In this paper, we study the processing of ad hoc star queries over hierarchically clustered fact tables.  ... 
doi:10.1016/b978-155860869-6/50070-6 dblp:conf/vldb/KarayannidisTSPMRFEB02 fatcat:uv7s77uizrat3ecxeijpayd53u

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.  ...  This transformation can significantly improve the processing of typical aggregation star queries on data warehouses that use hsurrogates and multidimensional access methods to hierarchically cluster fact  ... 
dblp:conf/dmdw/TsoisKST02 fatcat:avfxnetmfrhzzfiubf7dpjjs7y

Heuristic optimization of OLAP queries in multidimensionally hierarchically clustered databases

Dimitri Theodoratos, Aris Tsois
2001 Proceedings of the 4th ACM international workshop on Data warehousing and OLAP - DOLAP '01  
We exploit the different clustering features of the CSB star to efficiently process a class of typical OLAP queries.  ...  We present an architecture for multidimensional databases that are clustered with respect to multiple hierarchical dimensions. It is based on the star schema and is called CSB star.  ...  The dimension tables are organized using one-dimensional hierarchical clustering and encoding techniques, while the fact table is organized using a multidimensional access method.  ... 
doi:10.1145/512236.512243 dblp:conf/dolap/TheodoratosT01 fatcat:3a2xvdkkeffttpim5qg72eddxa

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

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  
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.  ...  This is a restricted form of snowflake schema, which minimises the number of tables while avoiding overlap between different dimensional hierarchies.  ...  A constellation schema consists of a set of star schemas with hierarchically linked fact tables.  ... 
dblp:conf/dmdw/MoodyK00 fatcat:u2ycsffcf5csfpx2gmb3mkpqhm

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  
The bottleneck in the evaluation of these queries is the join of the usually huge fact table with the restricted dimension tables (star-join).  ...  Recently, a multidimensional hierarchical clustering schema for star schemas is suggested.  ...  In order to achieve a multidimensional hierarchical clustering of the fact The fact table is clustered using a multidimensional access method on the compound surrogate attributes.  ... 
doi:10.1145/956069.956072 fatcat:dwsnxer2cfh4ral5rj7ijwrpjm

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  
The bottleneck in the evaluation of these queries is the join of the usually huge fact table with the restricted dimension tables (star-join).  ...  Recently, a multidimensional hierarchical clustering schema for star schemas is suggested.  ...  In order to achieve a multidimensional hierarchical clustering of the fact The fact table is clustered using a multidimensional access method on the compound surrogate attributes.  ... 
doi:10.1145/956060.956072 dblp:conf/dolap/Theodoratos03 fatcat:wypq7l6uqbbbzn3oduyxc5xl6i

Multi-Dimensional Database Allocation for Parallel Data Warehouses

Thomas Stöhr, Holger Märtens, Erhard Rahm
2000 Very Large Data Bases Conference  
We investigate how a multi-dimensional hierarchical data fragmentation of the fact table supports queries referencing different subsets of the schema dimensions.  ...  In this study, we consider the allocation of relational data warehouses based on a star schema and utilizing bitmap index structures.  ...  We assume typical star queries, also derived from APB- Star query processing with bitmap indices Such star queries involve a join between the fact table and one or more dimension tables.  ... 
dblp:conf/vldb/StohrMR00 fatcat:t7phux3nencjldbe4rcwbaaoeu

WARLOCK: A Data Allocation Tool for Parallel Warehouses

Thomas Stöhr, Erhard Rahm
2001 Very Large Data Bases Conference  
Data allocation approach We consider relational star schemas with denormalized, hierarchically organized dimension tables and one or more fact tables.  ...  The considered workload consists of a variety of multi-dimensional join and aggregation (star) queries on the fact tables that refer to dimension attributes.  ... 
dblp:conf/vldb/StohrR01 fatcat:zipdjvengnhkpeuuqzvymxecfy

The Generalized Pre-Grouping Transformation [chapter]

Aris Tsois, Timos Sellis
2003 Proceedings 2003 VLDB Conference  
These methods store the fact table of a data warehouse clustered according to the dimension hierarchies using special attributes called hierarchical surrogate keys.  ...  One important such optimization technique, called Hierarchical Pre-Grouping, uses the hierarchical surrogate keys in order to aggregate the fact table tuples as early as possible and to avoid redundant  ...  on hierarchically clustered fact tables.  ... 
doi:10.1016/b978-012722442-8/50063-x dblp:conf/vldb/TsoisS03 fatcat:x23rwd3dkve57ookie254w27ki

CUBE File: A File Structure for Hierarchically Clustered OLAP Cubes [chapter]

Nikos Karayannidis, Timos Sellis, Yannis Kouvaras
2004 Lecture Notes in Computer Science  
Hierarchical clustering has been proved an effective means for physically organizing large fact tables since it reduces significantly the I/O cost during ad hoc OLAP query evaluation.  ...  Our results show that the CUBE File outperforms the most effective method proposed up to now for hierarchically clustering the cube, resulting in 7-9 times less I/Os on average for all workloads tested  ...  Furthermore, the CUBE File fits perfectly to the processing framework for ad hoc OLAP queries over hierarchically clustered fact tables (i.e., cubes) proposed in our previous work [7] .  ... 
doi:10.1007/978-3-540-24741-8_36 fatcat:ujpbpl5vorfajfp3ei757nujci

Random access with a distributed Bitmap Join Index for Star Joins

Jaqueline J. Brito, Thiago Mosqueiro, Ricardo R. Ciferri, Cristina D.A. Ciferri
2020 Heliyon  
Indices improve the performance of relational databases, especially on queries that return a small portion of the data (i.e., low-selectivity queries).  ...  Star joins are particularly expensive operations that commonly rely on indices for improved performance at scale.  ...  Hermes Senger for allowing us to use his laboratory cluster infrastructure for tests. J.J. Brito  ... 
doi:10.1016/j.heliyon.2020.e03342 pmid:32099915 pmcid:PMC7030998 fatcat:pkzjpbfsurbfbl5tbah3vhl4o4

Data-driven distributed analytics and control platform for smart grid situational awareness

Christopher S Saunders, Guangyi Liu, Yang Yu, Wendong Zhu
2016 CSEE Journal of Power and Energy Systems  
such that it tightly corresponds to the naturally existing physical hierarchy of typical radial distribution networks, allowing for an organized and highly-localized set of data storage and analytics processes  ...  One important note is that the dimension tables must be replicated for each partition of the fact table when partitioning a fact table among different machines in a computational cluster, as displayed  ...  Typical star schema structure with fact and dimension tables, shown both before and after partitioning.  ... 
doi:10.17775/cseejpes.2016.00035 fatcat:ftdtd3e3e5dw3bxah22jdwzfu4

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.  ...  Star-modeled data warehouses with several fact tables are termed constellation schemas.  ...  A star schema is the simplest data warehouse schema. Shaped like a star, it consists of a single, central fact table linked to peripheral dimensions.  ... 
arXiv:1701.08033v1 fatcat:dfuzbfzhizhapnp5kuqxtujq6e

A Conceptual Model for Combining Enhanced OLAP and Data Mining Systems

Muhammad Usman, Sohail Asghar, Simon Fong
2009 2009 Fifth International Joint Conference on INC, IMS and IDC  
Online Analytical Processing (OLAP) was widely used to visualize complex data for efficient, interactive and meaningful analysis.  ...  On the other hand, data mining techniques (DM) are strong at detecting patterns and mining knowledge from historical data.  ...  The model we have devised to enhance OLAP is based on hierarchical clusters generated by hierarchical clustering tool.  ... 
doi:10.1109/ncm.2009.354 dblp:conf/ncm/UsmanAF09 fatcat:uxxhnbm3vfdmnmu7agul6oii4i
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