Re: updatable cursors and ORDER BY

On Thu, May 10, 2018 at 12:55:23PM -0400, Tom Lane wrote:
> Peter Eisentraut <peter.eisentraut@2ndquadrant.com> writes:
> > I think that last part isn't actually written down anywhere.  (It only
> > states the converse.)  How about a clarification like this:
> 
> > @@ -271,7 +271,10 @@ <title id="sql-declare-notes-title">Notes</title>
> >       and not use grouping or <literal>ORDER BY</literal>).  Cursors
> >       that are not simply updatable might work, or might not, depending on plan
> >       choice details; so in the worst case, an application might work in testing
> > -     and then fail in production.
> > +     and then fail in production.  If <literal>FOR UPDATE</literal> is
> > +     specified, then the cursor is guaranteed to be updatable, or the
> > +     <command>DECLARE</command> command will error if an updatable cursor
> > +     cannot be created for the supplied query.
> >      </para>
> 
> OK by me, except we don't usually use "error" as a verb.  Either "fail"
> or "throw an error" would read better IMO.  Or you could just stop with
> "guaranteed to be updatable"; I don't think the rest adds much.

I have done as you suggested and just used the first part;  patch
attached and backpatched.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +