Re: text vs. varchar

On Jul 21, 2010, at 9:05 AM, Thom Brown wrote:

> On 21 July 2010 16:58, Ben Chobot <bench(at)silentmedia(dot)com> wrote:
>> Is there any difference between "text" and "varchar" data types? (Not varchar(n), just varchar.) I can't see a different from the manual page, but I'm wondering about index usage or something similarly subtle.
>> --
>
> Here's what Tom Lane had to say on the matter when I asked previously:
>
> "There is some potential overhead from using varchar instead of text
> because of the extra dummy cast nodes that are likely to be present in
> your query expressions (since all the native functions are declared to
> take/return text, not varchar). In most cases I'd think you'd be
> hard-put to measure any difference though."

Thanks, this is precisely what I was looking for.