On Fri, 2007-09-21 at 17:36 +0200, Denes Daniel wrote: > Even though I forced the nested loop plan using both indexes (that > returns the rows in the correct order), there is a needless sort step on > the top, consuming half of the time even on such small tables. > Now it's clear why the planner did not choose this plan, why I had to > force it: because it isn't the best if the sort is still there. Ordering by parent, child is fairly common but the variation you've got here isn't that common. You'd need to make a case considering all the alternatives; nobody will agree without a balanced case that includes what is best for everyone. Your EXPLAIN looks edited. Have you also edited the sort costs? They look slightly higher than we might expect. Please provide the full normal EXPLAIN output. -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com ---------------------------(end of broadcast)--------------------------- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate
