All that WITH RECURSIVE does is allow a WITH query to refer to its own output. Beyond that there is no overhead. Here is the query plan I got for my above quer

All that WITH RECURSIVE does is allow a WITH query to refer to its own output. Beyond that there is no overhead. Here is the query plan I got for my above query: QUERY PLAN CTE Scan on path (cost=292.79..304.41 rows=581 width=104) CTE path -> Recursive Union (cost=0.00..292.79 rows=581 width=72) -> Index Scan using fs_pkey on fs (cost=0.00..8.27 rows=1 width=40) Index Cond: (id = 1) -> Hash Join (cost=0.33..27.29 rows=58 width=72) Hash Cond: (public.fs.parent_id = parentpath.id) -> Seq Scan on fs (cost=0.00..21.60 rows=1160 width=40) -> Hash (cost=0.20..0.20 rows=10 width=36) -> WorkTable Scan on path parentpath (cost=0.00..0.20 rows=10 width=36)