### Abstract

A top-κ OLAP query groups measures with respect to some abstraction level of interesting dimensions and selects the κ groups with the highest aggregate value. An example of such a query is "find the 10 combinations of product-type and month with the largest sum of sales". Such queries may also be applied in a spatial database context, where objects are augmented with some measures that must be aggregated according to a spatial division. For instance, consider a map of objects (e.g., restaurants), where each object carries some non-spatial measure (e.g., the number of customers served during the last month). Given a partitioning of the space into regions (e.g., by a regular grid), the goal is to find the regions with the highest number of served customers. A straightforward method to evaluate a top-κ OLAP query is to compute the aggregate value for each group and then select the groups with the highest aggregates. In this paper, we study the integration of the top-κ operator with the aggregate query processing module. For this, we make use of spatial indexes, augmented with aggregate information, like the aggregate R-tree. We device a branch-and-bound algorithm that accesses a minimal number of tree nodes in order to compute the top-κ groups. The efficiency of our approach is demonstrated by experimentation.

Original language | English |
---|---|

Pages (from-to) | 236-253 |

Number of pages | 18 |

Journal | Lecture Notes in Computer Science |

Volume | 3633 |

Publication status | Published - 2005 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Theoretical Computer Science
- Computer Science(all)

### Cite this

*Lecture Notes in Computer Science*,

*3633*, 236-253.

**Evaluation of top-k OLAP queries using aggregate R-trees.** / Mamoulis, Nikos; Bakiras, Spiridon; Kalnis, Panos.

Research output: Contribution to journal › Article

*Lecture Notes in Computer Science*, vol. 3633, pp. 236-253.

}

TY - JOUR

T1 - Evaluation of top-k OLAP queries using aggregate R-trees

AU - Mamoulis, Nikos

AU - Bakiras, Spiridon

AU - Kalnis, Panos

PY - 2005

Y1 - 2005

N2 - A top-κ OLAP query groups measures with respect to some abstraction level of interesting dimensions and selects the κ groups with the highest aggregate value. An example of such a query is "find the 10 combinations of product-type and month with the largest sum of sales". Such queries may also be applied in a spatial database context, where objects are augmented with some measures that must be aggregated according to a spatial division. For instance, consider a map of objects (e.g., restaurants), where each object carries some non-spatial measure (e.g., the number of customers served during the last month). Given a partitioning of the space into regions (e.g., by a regular grid), the goal is to find the regions with the highest number of served customers. A straightforward method to evaluate a top-κ OLAP query is to compute the aggregate value for each group and then select the groups with the highest aggregates. In this paper, we study the integration of the top-κ operator with the aggregate query processing module. For this, we make use of spatial indexes, augmented with aggregate information, like the aggregate R-tree. We device a branch-and-bound algorithm that accesses a minimal number of tree nodes in order to compute the top-κ groups. The efficiency of our approach is demonstrated by experimentation.

AB - A top-κ OLAP query groups measures with respect to some abstraction level of interesting dimensions and selects the κ groups with the highest aggregate value. An example of such a query is "find the 10 combinations of product-type and month with the largest sum of sales". Such queries may also be applied in a spatial database context, where objects are augmented with some measures that must be aggregated according to a spatial division. For instance, consider a map of objects (e.g., restaurants), where each object carries some non-spatial measure (e.g., the number of customers served during the last month). Given a partitioning of the space into regions (e.g., by a regular grid), the goal is to find the regions with the highest number of served customers. A straightforward method to evaluate a top-κ OLAP query is to compute the aggregate value for each group and then select the groups with the highest aggregates. In this paper, we study the integration of the top-κ operator with the aggregate query processing module. For this, we make use of spatial indexes, augmented with aggregate information, like the aggregate R-tree. We device a branch-and-bound algorithm that accesses a minimal number of tree nodes in order to compute the top-κ groups. The efficiency of our approach is demonstrated by experimentation.

UR - http://www.scopus.com/inward/record.url?scp=26444519163&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=26444519163&partnerID=8YFLogxK

M3 - Article

VL - 3633

SP - 236

EP - 253

JO - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

JF - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

SN - 0302-9743

ER -