From: "Shridhar Daithankar" <shridhar_daithankar@persistent.co.in>
To: pgsql-hackers@postgresql.org, pgsql-sql@postgresql.org
Date: Tue, 17 Jun 2003 12:35:00 +0530
MIME-Version: 1.0
Subject: Re: [HACKERS] Our FLOAT(p) precision does not conform to spec
Reply-To: shridhar_daithankar@persistent.co.in
Message-ID: <3EEF0AF4.16718.1AEA03@localhost>
In-reply-to: <7114.1055801746@sss.pgh.pa.us>
Content-type: text/plain; charset=US-ASCII
Content-transfer-encoding: 7BIT
Content-description: Mail message body

On 16 Jun 2003 at 18:15, Tom Lane wrote:
> This is a straightforward change and would not break pg_dump files,
> since fortunately pg_dump always references the underlying types and
> never refers to anything as FLOAT(p).  But I wonder whether it is
> likely to break many existing applications.  There is a hazard of some
> existing app asking for (what it thinks is) float8 and getting float4
> instead.

Especially apps. which rely on number(3) not to accept anything greate than +/-
999.

I hate the syntax of putting decimal digits as range checkers in SQL field. But 
oracle does that and consequently lot of oracle apps rely on it. I won't be 
surprised if float(p) notion brings same assurance to such app developers.

I think this would become and FAQ after changes are implemented. Who reads 
release notes anyway?..:-)
 
> Is it worth trying to provide some sort of backwards-compatibility mode?
> We could imagine adding a GUC variable to select binary or decimal
> precision, but I really don't want to.  It would increase the amount of
> work needed by more than an order of magnitude, and this problem doesn't
> seem worth it.  I'd rather just list this under Incompatibilities in the
> 7.4 release notes.

Is it possible to have float-2(p) and float-10(p)? Would it be adding code 
sections instead of replacing it?

That would be cleaner than GUC variable. Everything defaults to float-10(p) for 
backward compatibility for a period of a release and in 7.5, it gets switched 
to float-2(p). In the meantime, the behaviour remains available who cares to 
read the docs and notes.

Just a thought..

Bye
 Shridhar

--
Genderplex, n.:	The predicament of a person in a restaurant who is unable to	
determine his or her designated restroom (e.g., turtles and tortoises).		-- 
Rich Hall, "Sniglets"