Thread

Re: [HACKERS] varchar/char size

Thomas Lockhart <lockhart@alumni.caltech.edu> — 1998-01-08T03:07:13Z

> 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.

                                                         - Tom