public void setPositionData(boolean usePositionData) {
        this.usePositionData = usePositionData;
    }
Sets whether position data should be used when ranking this term item.
If set to false the search backend uses fast bit vector data structures when matching on this term
and only a few simple ranking features will be available when ranking this term.
Note that setting this to false also saves a lot of CPU during matching as bit vector data structures are used.
container-search/src/main/java/com/yahoo/prelude/query/Item.java