2009/12/18 Grzegorz Jaśkiewicz <gryz...@gmail.com>: > 2009/12/18 Robert Haas <robertmh...@gmail.com>: >> 2009/12/18 Grzegorz Jaśkiewicz <gryz...@gmail.com>: >>> On Fri, Dec 18, 2009 at 2:18 PM, Robert Haas <robertmh...@gmail.com> wrote: >>> >>>> NOT IN is the only that really kills you as far as optimization is >>>> concerned. IN can be transformed to a join. NOT IN forces a NOT >>>> (subplan)-type plan, which bites - hard. >>> >>> in a well designed database (read: not abusing NULLs) - it can be done >>> with joins too. >> >> But not by PostgreSQL, or so I believe. > > using left join ?
If at least one column in the subselect is strict, you can rewrite it that way yourself, but the optimizer won't do it. I wish it did, but I don't wish it badly enough to have written the code myself, and apparently neither does anyone else. ...Robert -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
