Re: Improve documentation for current_setting function

On Wed, Feb 20, 2019 at 12:59:45PM +0000, PG Doc comments form wrote:
> The following documentation comment has been logged on the website:
> 
> Page: https://www.postgresql.org/docs/11/functions-admin.html
> Description:
> 
> Hi.
> 
> Doc is not clear about what is returned if current_setting(
> 'app.not_existent', true ) is called.
> 
> Does it return empty string '', because return type is 'text' or it return
> NULL, because 'app.not_existent' does not exist

Testing shows:

    SELECT current_setting('asdf', true);
     current_setting
    -----------------
    
    
    \pset null (null)
    
    SELECT current_setting('asdf', true);
     current_setting
    -----------------
-->     (null)

How do you like the attached patch, which clarifies this?

-- 
  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 +