Re: Selecting a constant question

> -----Original Message-----
> From: Tom Lane [mailto:tgl@sss.pgh.pa.us]
> Sent: Monday, June 11, 2007 3:35 PM
> To: Dann Corbit
> Cc: Gregory Stark; Martijn van Oosterhout;
pgsql-hackers@postgresql.org;
> Larry McGhaw
> Subject: Re: [HACKERS] Selecting a constant question
> 
> "Dann Corbit" <DCorbit@connx.com> writes:
> > Giving me the information about the data type will be enough.  As an
> > example, in this case we have varchar data.  If the server should be
so
> > kind as to report varchar(1) for '1' or varchar(3) for '123' then I
> > would not have any difficulty binding the data to a grid.
> 
> This seems merest fantasy.  Reflect on multibyte character sets for a
> bit --- even if it's known that the column is varchar(3) there is no
> guarantee that the value will fit in 3 bytes.

If the server bound the data as UNICODE, then it will tell me
UNICODE(3).  I know how big this will be.

In the worst case scenario it will fit in 3*4 = 12 bytes.

If the server is built without UNICODE enabled, then it will definitely
fit in 3 bytes.