public void setIndexFacts(IndexFacts indexFacts) {
            this.indexFacts = indexFacts;
        }
Use this to override index settings for the searchers below
a given searcher, the easiest way to do this is to wrap the incoming
IndexFacts instance in a subclass. E.g.
execution.context().setIndexFacts(new WrapperClass(execution.context().getIndexFacts())).

@param indexFacts an instance to override the following searcher's view of the indexes
container-search/src/main/java/com/yahoo/search/searchchain/Execution.java