Prefix Filter

Filters documents that have fields containing terms with a specified prefix. Similar to phrase query, except that it acts as a filter. Can be placed within queries that accept a filter.

{
    "constant_score" : {
        "filter" : {
            "prefix" : { "user" : "ki" }
        }
    }
}

Caching

The result of the filter is cached by default. The _cache can be set to false in order not to cache it.