Re: Selecting a constant question

> -----Original Message-----
> From: Martijn van Oosterhout [mailto:kleptog(at)svana(dot)org]
> Sent: Monday, June 11, 2007 1:46 PM
> To: Dann Corbit
> Subject: Re: [HACKERS] Selecting a constant question
>
> On Mon, Jun 11, 2007 at 01:29:37PM -0700, Dann Corbit wrote:
> > Our application is using the libPQ interface to access postgres.
> >
> > The query is "select '123' from <tablename>" .. the table is not
> > important.
> >
> > After executing the query, we interrogate the metadata of the result
set
> > using the PQfsize, PQfmod and PQftype functions.
>
> Did you read the documentation of the PQfsize function?
>
> PQfsize returns the space allocated for this column in a database row,
> in other words the size of the server's internal representation of the
> data type. (Accordingly, it is not really very useful to clients.) A
> negative value indicates the data type is variable-length.
>
>
http://www.postgresql.org/docs/8.2/interactive/libpq-exec.html#LIBPQ-EXE
C-
> SELECT-INFO
>
> > The size of the column is returned as 65534 (or -2 if you consider
this
> > a signed short value)
>
> It's variable length, you can't say anything more.

So what you are saying is that the constant '1' is variable length, and
there is no way to find out the maximum length from the database.