Re: [HACKERS] Re: retrieving varchar size - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [HACKERS] Re: retrieving varchar size
Date
Msg-id 13212.893968565@sss.pgh.pa.us
Whole thread Raw
In response to Re: retrieving varchar size  (Michael Hirohama <kamesan@ricochet.net>)
Responses Re: retrieving varchar size  (Michael Hirohama <kamesan@ricochet.net>)
List pgsql-hackers
Michael Hirohama <kamesan@ricochet.net> wrote:
> The historical reason why the POSTGRES backend is required to send multiple
> result sets is to support cursors on queries involving type inheritance and
> anonymous target lists.
>     begin
>     declare c cursor for
>         select e.oid, e.* from EMP* e
>     fetch 10 in c
>     ...
> To handle the command sequence above, frontend applications would need to
> be provided with a new result descriptor when the "fetch 10 in c" crosses a
> result set boundary.

I tried this and was unable to produce a failure.  It looks like the
select only returns the set of fields applicable to the base class,
regardless of what additional fields may be possessed by some
subclasses.  Which, in fact, is more or less what I'd expect.

Is Michael remembering some old behavior that is no longer implemented?
And if so, is the old or new behavior the correct one?

            regards, tom lane

pgsql-hackers by date:

Previous
From: aldev@hotmail.com
Date:
Subject: PostgreSQL HOWTO Version 6.0 released
Next
From: "Thomas G. Lockhart"
Date:
Subject: Re: CODE ANALYSIS FOR (an apparent error in answer from "##" (closest proximity)operator)