NSJ: an efficient non-blocking spatial join algorithm

  • Authors:

  • Guifen Tang;Jose E. Córcoles;Ning Jing

  • Affiliations:

  • National University of Defense Technology, ChangSha, China;Castilla-La Mancha University, Albacete, Spain;National University of Defense Technology, ChangSha, China

  • Venue:
  • GIS '06 Proceedings of the 14th annual ACM international symposium on Advances in geographic information systems
  • Year:
  • 2006

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Abstract

This paper introduces an efficient non-blocking spatial join (NSJ, for short) algorithm to deal with spatial objects from remote sources via underlying network. The objectives of NSJ are: (1) start reporting the first output join results as soon as possible, and (2) minimize the cost for output the remaining results. As some other previous non-blocking join algorithms, NSJ includes two stages: memory-join stage and disk-join stage The memory-join stage employs a join process as along as receiving spatial objects, and the disk-join stage is responsible for the uncompleted join process during the memory-join stage after all spatial objects are received completely. We propose a dynamic concurrent flush policy(DCFP) based on resident degree to process memory overflow, which makes join process in memory-join stage more efficiently. We also develop an optimal data access schedule algorithm based on BEA (Bond Energy Algorithm) to reduce redundant I/O and CPU cost in disk-join stage. Extensive experiments prove that our technique delivers result significantly more efficient than the previous methods.