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Transform-Space View: Performing Spatial Join in the Transform Space Using Original-Space Indexes

Transform-Space View: Performing Spatial Join in the Transform Space Using Original-Space Indexes. Min-Jae Lee, Student Member, IEEE Kyu-Young Whang, Senior Member, IEEE Wook-Shin Han, Member, IEEE Il-Yeol Song, Member, IEEE Computer Society Presented by Robert Tallon. Spatial Joins.

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Transform-Space View: Performing Spatial Join in the Transform Space Using Original-Space Indexes

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  1. Transform-Space View:Performing Spatial Joinin the Transform SpaceUsing Original-Space Indexes Min-Jae Lee, Student Member, IEEE Kyu-Young Whang, Senior Member, IEEE Wook-Shin Han, Member, IEEE Il-Yeol Song, Member, IEEE Computer Society Presented by Robert Tallon

  2. Spatial Joins • Find all pairs of objects that satisfy a given spatial relationship. • Current spatial join algorithms include those that use indexes on both files and those that do not.

  3. Index Join Algorithms • O-Space IJA: Indexes are created in the original space. • T-Space IJA: Indexes are created in the transform space.

  4. Original Space IJAs • Use indexes that consider the extents of objects in the o-space • Based on the R-tree family. • Depth-First Traversal R-tree Join: local optimization of page access sequence. • Breadth-First Traversal R-tree Join: Global optimization of page access sequence with drawback of disk/memory overhead.

  5. Transform Space IJAs • Use indexes in which objects are considered as points with no extents in the t-space. • Based on Multi-Level Grid File. • Advantage: Achieves global optimization without incurring disk/memory overhead. • Drawback: Can not be applied to o-space indexed files.

  6. Transform-space View • A virtual t-space index for an o-space index. • Allows the application of a t-space IJA to an o-space index. • Applicable to tree structured o-space indexes, where regions are represented as minimum bounding rectangles. (MBRs)

  7. Tree Representations

  8. MBR

  9. Graphical Representations

  10. Containment Relationships

  11. Horizontal Containment

  12. Vertically Adjacent Strips

  13. TSVJA key Points • Utilize Adjacency relationships to minimize one pass buffer size. • ARM -Space filling curve with smallest one pass buffer size.

  14. Arm Order

  15. Conclusions • Dynamic interpretation of o-space indexes. • Global optimization of page access sequence without memory or disk overhead. • Allows t-space type algorithm to be applied to o-space indexes without modifying the original structure

  16. QUESTIONS?

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