Constant GID_MAPPING_CTES 

const GID_MAPPING_CTES: &str = "\
    builtin_index_gid_mappings AS (
        SELECT
            's' || (data->'value'->>'catalog_id') AS id,
            data->'key'->>'object_name' AS name
        FROM mz_internal.mz_catalog_raw
        WHERE
            data->>'kind' = 'GidMapping' AND
            data->'key'->>'object_type' = '6'
    ),
    on_gid_mappings AS (
        SELECT
            's' || (data->'value'->>'catalog_id') AS id,
            data->'key'->>'schema_name' AS schema_name,
            data->'key'->>'object_name' AS object_name
        FROM mz_internal.mz_catalog_raw
        WHERE data->>'kind' = 'GidMapping'
    )";

Helper CTEs over GidMapping rows used to look up the system id of a builtin index by name and of the relation it indexes by (schema, name).