Mario Splivalo <mario.splivalo@xxxxxxxxxx> writes: > Limit (cost=0.00..415.91 rows=21 width=8) (actual > time=11263.089..11263.089 rows=0 loops=1) > -> Nested Loop (cost=0.00..186249.55 rows=9404 width=8) (actual > time=11263.087..11263.087 rows=0 loops=1) > Why is planner using NestedLoops, Because it thinks the LIMIT will kick in and end the query when the join is only 21/9404ths (ie, a fraction of a percent) complete. A NestLoop results in saving a lot of work in that situation, whereas hash-and-sort has to do the whole join despite the LIMIT. What you need to look into is why the estimated join size is 9400 rows when the actual join size is zero. Are both tables ANALYZEd? Are you intentionally selecting rows that have no join partners? regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
