From 10fb48d66de76e7dc1e36ef18af502ed9600352f Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 2 Jul 2015 16:40:55 -0400
Subject: Add an optional missing_ok argument to SQL function
 current_setting().

This allows convenient checking for existence of a GUC from SQL, which is
particularly useful when dealing with custom variables.

David Christensen, reviewed by Jeevan Chalke
---
 doc/src/sgml/func.sgml | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

(limited to 'doc')

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 99923f46bca..76f77cb0fcf 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -16444,7 +16444,7 @@ SELECT collation for ('foo' COLLATE "de_DE");
         <indexterm>
          <primary>current_setting</primary>
         </indexterm>
-        <literal><function>current_setting(<parameter>setting_name</parameter>)</function></literal>
+        <literal><function>current_setting(<parameter>setting_name</parameter> [, <parameter>missing_ok</parameter> ])</function></literal>
        </entry>
        <entry><type>text</type></entry>
        <entry>get current value of setting</entry>
@@ -16492,6 +16492,11 @@ SELECT current_setting('datestyle');
  ISO, MDY
 (1 row)
 </programlisting>
+
+    If there is no setting named <parameter>setting_name</parameter>,
+    <function>current_setting</function> throws an error
+    unless <parameter>missing_ok</parameter> is supplied and is
+    <literal>true</literal>.
    </para>
 
    <para>
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