Thanks for elaborating on that Tom. I understand what it means by extension now.
The reason I looked into it in the first place was because someone at work said that varchar was an alias for text, which didn't quite sound right. And I had automatically used the data-type "text" for any varying text fields since there is no performance/storage hit in PostgreSQL for such data, unlike some other RBDMSs. It's interesting to know of the non-nativity of varchar, even if the practical differences are negligable. :)
Thanks again
Thom
2009/1/27 Tom Lane
<tgl@sss.pgh.pa.us>Thom Brown <
thombrown@gmail.com> writes:
> The reason I ask is because the documentation says "If character varying is
> used without length specifier, the type accepts strings of any size. The
> latter is a PostgreSQL extension." I wasn't sure if such an extension meant
> there was a level of over-head involved, or reduced its indexability.
anything about performance.
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.
regards, tom lane