I really thought that Postgresql would rewrite a query from
select * from file a, file_tag b, tag c where a.id_file=b.id_file and b.id_tag=c.id_tag and a.id_file=10000001000000 to something like: select * from (file a inner join file_tag b on (a.id_file=b.id_file)) inner join tag c on (b.id_tag=c.id_tag) where a.id_file=10000001000000 However this is not the case! I have a many-to-many relation between 2 tables (tag and file). tag has 40000 rows and file has 5 millions rows. file_tag has 50 millions rows. In this setup, the first select takes a couple of minutes to complete while the second query takes only a second to complete. Is this a normal expected behavior? Shouldn't Postgresql be able to rewrite the query correctly? _________________________________________________________________ Få 250 MB gratis lagerplads på MSN Hotmail: http://www.hotmail.com ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
