An overview of spatial indexes in the geodatabase

ArcGIS uses spatial indexes to improve spatial query performance on feature classes. Identifying a feature, selecting features by pointing or dragging a box, and panning and zooming all require ArcMap to use the spatial index to locate features.

When you create an empty feature class or import data to create a new feature class in a geodatabase from ArcGIS, a spatial index is created on the feature class. The spatial index is used during editing and the loading of data.

*When you create empty feature classes in geodatabases in DB2, spatial indexes are not created.

Spatial indexes work differently depending on the data source. Feature classes in the following geodatabase types use grid-based spatial indexes:

• Personal geodatabases
• File geodatabases
• Geodatabases in DB2
• Geodatabases in Oracle that use Esri ST_Geometry or binary geometry storage
• Geodatabases in SQL Server that use binary geometry storage

Feature classes in Oracle that use Oracle Spatial (SDO_Geometry) storage, Informix, and PostgreSQL do not use grid-based spatial indexes—they use an R-tree index. Similarly, feature classes that use SQL Server spatial types do not use an Esri grid-based spatial index.