SELECT h.schema_name,
    h.table_name,
    h.id AS table_id,
    h.associated_table_prefix,
    row_estimate.row_estimate
   FROM _timescaledb_catalog.hypertable h
     CROSS JOIN LATERAL ( SELECT sum(cl.reltuples) AS row_estimate
           FROM _timescaledb_catalog.chunk c
             JOIN pg_class cl ON cl.relname = c.table_name
          WHERE c.hypertable_id = h.id
          GROUP BY h.schema_name, h.table_name) row_estimate
ORDER BY schema_name, table_name;