### Description

Tracking total hits sometimes has a non-negligible impact on performance. We should disable it when not strictly required.
x-pack/plugin/sql/src/main/java/org/elasticsearch/xpack/sql/execution/search/Querier.java
private static final List<? extends Bucket> EMPTY_BUCKET = singletonList(new Bucket() {
            @Override
            public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
                throw new SqlIllegalArgumentException("No group-by/aggs defined");
            }
            @Override
            public Object getKey() {
                throw new SqlIllegalArgumentException("No group-by/aggs defined");
            }
            @Override
            public String getKeyAsString() {
                throw new SqlIllegalArgumentException("No group-by/aggs defined");
            }
            @Override
            public long getDocCount() {
                throw new SqlIllegalArgumentException("No group-by/aggs defined");
            }
            @Override
            public Aggregations getAggregations() {
                throw new SqlIllegalArgumentException("No group-by/aggs defined");
            }
        });
        ImplicitGroupActionListener(
            ActionListener<Page> listener,