Querying spatial data in column stores using grid-order scans

Patent metadata

Field	Value
Publication number	US-9720931-B2
Application number	US-201414274548-A
Country	US
Kind code	B2
Filing date	May 9, 2014
Priority date	May 9, 2014
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A query of spatial data is received by a database comprising a columnar data store storing data in a column-oriented structure. Thereafter, a minimal bounding rectangle associated with the query is identified using a grid order scanning technique. The spatial data set corresponding to the received query is then mapped to physical storage in the database using the identified minimal bounding rectangle so that the spatial data set can be retrieved. Related apparatus, systems, techniques and articles are also described.

First claim

What is claimed is:

1. A method implemented on one or more systems comprising one or more programmable processors, the method comprising:
mapping spatial data stored in a database comprising a columnar data store storing the spatial data in a column-oriented structure, the mapping comprising preserving spatial proximity of a plurality of spatial point objects when the spatial data are physically stored using a grid ordering comprising:
dividing a bounded space containing the spatial point objects into a grid having fixed boundaries and comprising rectangular cells,
indexing the cells of the grid, wherein the indexing comprises defining a minimum bounding box for each spatial point object of the plurality of spatial point objects, the minimum bounding box enclosing the spatial point object, storing a grid-identifier to at least one cell of the grid for each minimum bounding box, and creating index vectors to represent the cells of the grid and the grid identifiers of the minimum bounding boxes, and
assigning any minimum bounding boxes having a size above a certain level to an overflow cell;

identifying a target minimum bounding box based on a received query of the spatial data, the identifying comprising scanning the cells of the grid and the exclusive ordering values using the index vectors;
determining, based on the mapping and the identified target minimum bounding box, a spatial data set corresponding to the received query and a physical storage location in the database from which to retrieve the spatial data set, the determining further comprising checking the overflow cell for the received query; and
retrieving the spatial data set from the physical storage location based on the determining.

2. A method as in claim 1 , wherein the grid ordering comprises the grid of cells being of uniform length along each axis of a plurality of axes.

3. A method as in claim 2 , wherein the indexing of the cells of the grid comprises indexing the cells with a space-filling curve.

4. A method as in claim 3 , wherein the space-filling curve comprises a Hilbert space-filling curve.

5. A method as in claim 2 , further comprising redundantly storing a reference to each minimum bounding box for every cell the minimum bounding box intersects.

6. A method as in claim 2 , further comprising storing a reference to each minimum bounding box only for a cell at which a corner of the minimum bounding box is inside.

7. A method as in claim 6 , wherein a parameter defines a number of adjacent cells per dimension extending from the corner.

8. A method as in claim 1 , wherein the size is based on a number of adjacent cells per dimension that the minimum bounding box can intersect.

9. A method as in claim 1 , wherein the grid ordering comprises the grid of cells having non-uniform dimensions.

10. A non-transitory computer program product storing instructions which, when executed by at least one data processor forming part of at least one computing system, result in operations comprising:
mapping spatial data stored in a database comprising a columnar data store storing the spatial data in a column-oriented structure, the mapping comprising preserving spatial proximity of a plurality of spatial point objects when the spatial data are physically stored using a grid ordering comprising:
dividing a bounded space containing the spatial point objects into a grid having fixed boundaries and comprising rectangular cells,
indexing the cells of the grid, wherein the indexing comprises defining a minimum bounding box for each spatial point object of the plurality of spatial point objects, the minimum bounding box enclosing the spatial point object, storing a grid-identifier to at least one cell of the grid for each minimum bounding box, and creating index vectors to represent the cells of the grid and the grid identifiers of the minimum bounding boxes, and
assigning any minimum bounding boxes having a size above a certain level to an overflow cell;

identifying a target minimum bounding box based on a received query of the spatial data, the identifying comprising scanning the cells of the grid and the exclusive ordering values using the index vectors;
determining, based on the mapping and the identified target minimum bounding box, a spatial data set corresponding to the received query and a physical storage location in the database from which to retrieve the spatial data set, the determining further comprising checking the overflow cell for the received query; and
retrieving the spatial data set from the physical storage location based on the determining.

11. A computer program product as in claim 10 , wherein the grid ordering comprises the grid of cells being of uniform length along each axis of a plurality of axes.

12. A computer program product as in claim 11 , wherein the indexing of the cells of the grid comprises indexing the cells with a space-filling curve.

13. A computer program product as in claim 12 , wherein the space-filling curve comprises a Hilbert space-filling curve.

14. A computer program product as in claim 11 , wherein the operations further comprise redundantly storing a reference to each minimum bounding box for every cell the minimum bounding box intersects.

15. A computer program product as in claim 11 , wherein the operations further comprise a reference to each minimum bounding box only for a cell at which a corner of the minimum bounding box is inside.

16. A computer program product as in claim 15 , wherein a parameter defines a number of adjacent cells per dimension extending from the corner.

17. A computer program product as in claim 15 , wherein the operations further comprise any minimum bounding boxes having a size above a certain level to an overflow cell.

18. A system comprising:
a database comprising a columnar data store storing data in a column-oriented structure;
at least one data processor; and
memory storing instructions which, when executed by the at least one data processor, result in operations comprising:
mapping spatial data stored in a database comprising a columnar data store storing the spatial data in a column-oriented structure, the mapping comprising preserving spatial proximity of a plurality of spatial point objects when the spatial data are physically stored using a grid ordering comprising:
dividing a bounded space containing the spatial point objects into a grid having fixed boundaries and comprising rectangular cells,
indexing the cells of the grid, wherein the indexing comprises defining a minimum bounding box for each spatial point object of the plurality of spatial point objects, the minimum bounding box enclosing the spatial point object, storing a grid-identifier to at least one cell of the grid for each minimum bounding box, and creating index vectors to represent the cells of the grid and the grid identifiers of the minimum bounding boxes, and
assigning any minimum bounding boxes having a size above a certain level to an overflow cell;

identifying a target minimum bounding box based on a received query of the spatial data, the identifying comprising scanning the cells of the grid and the exclusive ordering values using the index vectors;
determining, based on the mapping and the identified target minimum bounding box, a spatial data set corresponding to the received query and a physical storage location in the database from which to retrieve the spatial data set, the determining further comprising checking the overflow cell for the received query; and
retrieving the spatial data set from the physical storage loca

Assignees

• Tyercha Edward-Robert
• Kazmaier Gerrit Simon
• Gildhoff Hinnerk
• Pekel Isil
• Volker Lars
• Grouisborn Tim
• Sap Se

Inventors

• Tyercha Edward-Robert
• Kazmaier Gerrit Simon
• Gildhoff Hinnerk
• Pekel Isil
• Volker Lars
• Grouisborn Tim

Classifications

• G06F17/30241 Primary

  Physics · mapped topic

• G06F17/30917

  Physics · mapped topic

• G06F17/3087

  Physics · mapped topic

• G06F17/30315

  Physics · mapped topic

• G06F16/29 Primary

  Geographical information databases · CPC title