The technique described herein provides a way to summarize data and can also minimize unnecessary accesses to a data store. In one embodiment, the technique creates and stores an adaptive range filter that contains a compact summary of the contents of an index for a data store in the form of a trie data structure. Before accessing the index of the data store in response to a query, the technique checks the filter to determine whether the data store does not contain any keys for a specific range of data. If the adaptive range filter indicates that the index contains no keys satisfying the query predicate, the index of the data store and the data itself is not accessed. The adaptive range filter of the technique supports both range predicates and equality predicates. It is adaptive to changes in data and queries by learning the query and data distribution.