I've dealt with recursive queries many many times. For legacy production systems I stick to Oracle's CONNECT BY statement and half joins to keep performance oka

I've dealt with recursive queries many many times. For legacy production systems I stick to Oracle's CONNECT BY statement and half joins to keep performance okay. Most of the tables I deal with typically have 80 million rows with a fanout of 1:2.5 and a average depth of ~3. A better solution is to create a temporary table to insert results in as you go if you can't afford extra DB results and perform additional inserts to that table in order to effectively take advantage of shared memory on the server side. The second better result is to effectively flatten out the rows as a closure table.