Using pgr_drivingDistance with large ids

Question

I have little experience with postgres and none with pgrouting.

I'm trying to use the pgr_drivingDistance function with Open Street Map data (generated through osm2po), but whenever I run my query:

SELECT pgr_drivingDistance('SELECT id, osm_source_id::int4 AS source, osm_target_id::int4 AS target, cost::float8 AS cost FROM nyc_2po_4pgr', 85, 2, false, false);

I get ERROR: integer out of range—I assume because some of the osm_source_ids I'm getting in don't fit in an int4. Is that what's going on?

I'm using a small subsection of the OSM data, so I assume I could squash the source_ids/target_ids into an int4 range. How would I do that?

Alternatively, is there a way to make the pgr_drivingDistance work with the larger source/target ids?

Answer 1

osm_source_id::int4 casts an 8-Bytes-Long-Integer down to a 4-Byter. Hence the error message is correct. Anyway, osm_source_id is the wrong attribute. Use source (target) instead.