Re: psql performance

On Thu, Apr 14, 2005 at 08:17:55PM -0700, Joshua D. Drake wrote:
> Joseph Shraibman wrote:
> >It doesn't matter what the query is. The problem happens before it even
> >runs the query. Just try pasting select
> >'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' union select
> >'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' union select
> >'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' union select
>
> I can not reproduce your problem on 8.0.2.

Nor I with 7.2.7, 7.3.9, 7.4.7, 8.0.2, or 8.1devel.

What happens if you edit the query with \e and then issue it, or
if you put the query in a file and use \i to read it? Could you
tell us something about your environment -- OS, window manager,
terminal, etc.?

> >Incidentally when I did that I only got back one row. What's up with that?

That's how UNION works:

http://www.postgresql.org/docs/7.4/interactive/queries-union.html

"Furthermore, it eliminates all duplicate rows, in the sense of
DISTINCT, unless UNION ALL is used."

--
Michael Fuhr
http://www.fuhr.org/~mfuhr/