Thread

Re: [HACKERS] varchar/char size

Thomas Lockhart <lockhart@alumni.caltech.edu> — 1998-01-08T03:20:14Z

Bruce Momjian wrote:

> >
> > > Does someone want to remind me why we allocate the full size for char()
> > > and varchar(), when we really can just allocate the size of the given
> > > string?
> > > I relize char() has to be padded, but why varchar()?
> >
> > > In my experience, char() is full size as defined by create, and
> > > varchar() is the the size of the actual data in the field, like text,
> > > but with a pre-defined limit.
> >
> > Well, in many relational databases access can be optimized by having
> > fixed-length tuple storage structures. Also, it allows re-use of deleted
> > space in storage pages. It may be that neither of these points have any
> > bearing on Postgres, and never will, but unless that clearly the case then
> > I would be inclined to keep the storage scheme as it is currently.
>
> With Ingres and Informix char() is fixed size, while varchar() is
> VARiable size.

Go for it. Let me know if I can help with testing or anything...

                                        - Tom