presto-main/src/main/java/io/prestosql/operator/index/IndexLookupSource.java/IndexLookupSource/IndexLookupSource
class IndexLookupSource:    public IndexLookupSource(IndexLoader indexLoader)
    {
        this.indexLoader = requireNonNull(indexLoader, "indexLoader is null");
        this.indexedData = indexLoader.getIndexSnapshot();
    }