| Full text | |
| Author(s): |
Lopes Siqueira, Thiago Luis
[1, 2]
;
de Aguiar Ciferri, Cristina Dutra
[3]
;
Times, Valeria Cesario
[4]
;
Ciferri, Ricardo Rodrigues
[1]
Total Authors: 4
|
| Affiliation: | [1] Univ Fed Sao Carlos, Dept Comp Sci, BR-13565905 Sao Carlos - Brazil
[2] Sao Paulo Fed Inst Educ Sci & Technol IFSP, BR-13565905 Sao Carlos - Brazil
[3] Univ Sao Paulo, Dept Comp Sci, BR-13560970 Sao Carlos - Brazil
[4] Univ Fed Pernambuco, Informat Ctr, BR-50740560 Recife, PE - Brazil
Total Affiliations: 4
|
| Document type: | Journal article |
| Source: | GEOINFORMATICA; v. 16, n. 1, p. 165-205, JAN 2012. |
| Web of Science Citations: | 15 |
| Abstract | |
Spatial data warehouses (SDWs) allow for spatial analysis together with analytical multidimensional queries over huge volumes of data. The challenge is to retrieve data related to ad hoc spatial query windows according to spatial predicates, avoiding the high cost of joining large tables. Therefore, mechanisms to provide efficient query processing over SDWs are essential. In this paper, we propose two efficient indices for SDW: the SB-index and the HSB-index. The proposed indices share the following characteristics. They enable multidimensional queries with spatial predicate for SDW and also support predefined spatial hierarchies. Furthermore, they compute the spatial predicate and transform it into a conventional one, which can be evaluated together with other conventional predicates by accessing a star-join Bitmap index. While the SB-index has a sequential data structure, the HSB-index uses a hierarchical data structure to enable spatial objects clustering and a specialized buffer-pool to decrease the number of disk accesses. The advantages of the SB-index and the HSB-index over the DBMS resources for SDW indexing (i.e. star-join computation and materialized views) were investigated through performance tests, which issued roll-up operations extended with containment and intersection range queries. The performance results showed that improvements ranged from 68% up to 99% over both the star-join computation and the materialized view. Furthermore, the proposed indices proved to be very compact, adding only less than 1% to the storage requirements. Therefore, both the SB-index and the HSB-index are excellent choices for SDW indexing. Choosing between the SB-index and the HSB-index mainly depends on the query selectivity of spatial predicates. While low query selectivity benefits the HSB-index, the SB-index provides better performance for higher query selectivity. (AU) | |
| FAPESP's process: | 09/06052-7 - Access methods for improving query performance of non-conventional databases |
| Grantee: | Cristina Dutra de Aguiar |
| Support Opportunities: | Regular Research Grants |