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11.5.9 Optimizing Spatial Analysis

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For MyISAM and InnoDB tables, search operations in columns containing spatial data can be optimized using SPATIAL indexes. The most typical operations are:

  • Point queries that search for all objects that contain a given point

  • Region queries that search for all objects that overlap a given region

MySQL uses R-Trees with quadratic splitting for SPATIAL indexes on spatial columns. A SPATIAL index is built using the minimum bounding rectangle (MBR) of a geometry. For most geometries, the MBR is a minimum rectangle that surrounds the geometries. For a horizontal or a vertical linestring, the MBR is a rectangle degenerated into the linestring. For a point, the MBR is a rectangle degenerated into the point.

It is also possible to create normal indexes on spatial columns. In a non-SPATIAL index, you must declare a prefix for any spatial column except for POINT columns.

MyISAM and InnoDB support both SPATIAL and non-SPATIAL indexes. Other storage engines support non-SPATIAL indexes, as described in Section 13.1.15, “CREATE INDEX Syntax”.


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Document created the 26/06/2006, last modified the 26/10/2018
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