For read and take operations, XAP iterates non-null values that match template or SQLQuery criteria, returning matches from the Space. This process can be time consuming, especially when there are many potential matches. To improve performance, it is possible to index one or more Space class properties. The Space maintains additional data for indexed properties, which shortens the time required to determine a match, thus improving performance.
Basic index types
Indexing Nested properties
An index can be defined on a nested property to improve performance of nested queries.
An index can be defined on a Collection property (java.util.Collection implementation).
Compound indexes can be defined using multiple class properties.
Unique constraints can be defined for a property or properties of a space class.