# Subset Matching

This example demonstrates AutoComplete's `queryMatchSubset` property. The first instance of AutoComplete has `queryMatchSubset` enabled for maximum cache performance such that as you type, the query is searched within previously cached results. For best results, the DataSource should return a complete set of results when a single letter is queried such that subset matching will also return a complete set of results.

The second AutoComplete instance does not enable `queryMatchSubset` so each typed letter results in a new request to the server.

Note the custom CSS that is needed for stacking AutoComplete instances.

Note: The flat-file database accessed here has a limited number of terms; for best results, type one-letter at at time and let the AutoComplete instance return — if you type a full, highly-specifc phrase (such as your name) you'll probably get no results from the small dataset.

First AutoComplete instance enables queryMatchSubset:
Second AutoComplete instance does not enable queryMatchSubset: