Function summary_query_shape 

pub fn summary_query_shape(
    query: &str,
) -> Result<Option<SummaryQueryShape>, SparqlError>

Classify SPARQL queries that can be answered exactly from the pyramid summary’s per-predicate totals. This is intentionally conservative: anything with constants, repeated variables, filters, joins, paths, named graphs, ORDER BY, OFFSET/LIMIT, or non-summary-safe aggregates still requires the index. The only accepted DISTINCT shape is a predicate list over one fully unbound triple pattern.