Hello, I have a strange performance problem with postgresql 8.3 (shipped with ubuntu hardy) and a query that seems very simple: explain analyze SELECT * FROM (part LEFT OUTER JOIN part_lang ON part.id = part_lang.id) WHERE part.parent = 49110; query plan here: http://front7.smartlounge.be/~kervel/queryplan.txt the query does not return a single row the table "part" and "part_lang" have a whole lot of tables inheriting them, most of the inheriting tables only contain a few rows. this turns this query in an append of a whole lot of seq scan/ index scan's. These scans are predictably quick, but the "append" takes 5 seconds (and the numbers of the scans do not add up to the append actual time) if i leave out the "outer join" performance is okay: SELECT * FROM part WHERE part.parent = 49110; if i then add a "order by sequence number" the performance is bad again: SELECT * FROM part WHERE part.parent = 49110 order by sequencenumber; I'm a bit stuck with this problem, and i don't know how to continue finding out why. Does someone have an explanation / possible solution for this performance ? We use a similar scheme on a lot of other projects without problems (but this time, the number of tables inheriting from part is a bit bigger). Thanks a lot in advance, greetings, Frank -- ========================= Frank Dekervel frank.dekervel@xxxxxxxxxxxxxx ========================= Smartlounge JP Minckelersstraat 78 3000 Leuven phone:+32 16 311 413 fax:+32 16 311 410 mobile:+32 473 943 421 ========================= http://www.smartlounge.be =========================
