Re: [QUESTIONS] DANGER WILL ROBINSON!

Marc G. Fournier <scrappy@hub.org>

From: The Hermit Hacker <scrappy@hub.org>
To: Bruce Momjian <maillist@candle.pha.pa.us>
Cc: Karl Denninger <karl@mcs.net>, hackers@postgreSQL.org
Date: 1998-03-09T18:02:26Z
Lists: pgsql-hackers
Redirected to 'the proper list' - pgsql-hackers@postgresql.org

On Mon, 9 Mar 1998, Bruce Momjian wrote:

> > 
> > WARNING!
> > 
> > Postgres 6.3 has MAJOR trouble with btree-indexed text fields.
> > 
> > Performance levels are *10x* worse than the same indexed fields in "varchar"
> > format!
> > 
> > Be EXTREMELY careful - I got bit in the ass by this this morning, and it was
> > very fortunate that I figured out what was going on.
> > 
> > The reason I changed this over was that I had dumped the table and it came
> > out of the pg_dump program with a negative size.  So I figured I'd change it
> > to TEXT and that would resolve the problem.  BIG mistake.
> > 
> > Be on guard for this folks.
> > 
> > Developers, you might want to look into this - there's no good reason for
> > this kind of behavior, is there?
> 
> No good reason at all.  As far as I know, text and varchar() behave
> identically in the backend, except for the input functions which limit
> the length of varchar.

	Karl...just curious, but what does an 'explain' show for the two
different situations?  10x worse almost sounds like the indices aren't
even being used, don't they?