Guidelines for choosing a spatial index grid size

The guidelines provided in this topic can help improve the performance of spatial queries when you have to manually calculate the size of a spatial grid index in Oracle and DB2.

Grid cell size impacts the size of the spatial index table. Setting up the spatial index means balancing the cell sizes—smaller cell sizes mean more cells per shape, which require more entries in the spatial index table.

If you are using third-party client applications, the applications and spatial data profiles can vary from one system to another. In these cases, you may need to experiment with the spatial index, trying different cell sizes and different grid-level configurations.

If you create your data through ArcGIS Desktop, the spatial grid index is calculated for you. In most cases, these grid sizes should not need to be altered. However, if you find the grids are not meeting your needs, follow the same guidelines for choosing a spatial index grid size as you would for spatial tables created with third-party clients.

For more information about the DB2 Spatial Extender grid index, see the IBM DB2 Spatial Extender and Geodetic Extender User's Guide and Reference.

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