Back out:

>  Attached is a patch that addressed all the discussed issues
>  that did not break backward compatability, including the
>  ability to output ISO-8601 compliant intervals by setting
>  datestyle to iso8601basic.

Author: bmomjian

doc/src/sgml/datatype.sgml

@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.138 2003/12/20 16:06:54 momjian Exp $
+$PostgreSQL: pgsql/doc/src/sgml/datatype.sgml,v 1.139 2003/12/21 04:34:35 momjian Exp $
 -->
 
  <chapter id="datatype">
@@ -1785,55 +1785,6 @@ January 8 04:05:06 1999 PST
       <replaceable>p</replaceable> should be between 0 and 6, and
       defaults to the precision of the input literal.
      </para>
-
-
-     <para>
-      Alternatively, <type>interval</type> values can be written as 
-      ISO 8601 time intervals, using the "Format with time-unit designators".
-      This format always starts with the character <literal>'P'</>, followed 
-      by a string of values followed by single character time-unit designators.
-      A <literal>'T'</> separates the date and time parts of the interval.
-     </para>
-
-     <para>
-       Format:  PnYnMnDTnHnMnS
-     </para>
-     <para>
-       In this format, <literal>'n'</> gets replaced by a number, and 
-       <literal>Y</> represents years, 
-       <literal>M</> (in the date part) months,
-       <literal>D</> months,
-       <literal>H</> hours,
-       <literal>M</> (in the time part) minutes,
-       and <literal>S</> seconds.
-     </para>
-      
-
-     <table id="interval-example-table">
-	   <title>Interval Example</title>
-	   <tgroup cols="2">
-		<thead>
-		 <row>
-		  <entry>Traditional</entry>
-		  <entry>ISO-8601 time-interval</entry>
-		 </row>
-		</thead>
-		<tbody>
-		 <row>
-		  <entry>1 month</entry>
-		  <entry>P1M</entry>
-		 </row>
-		 <row>
-		  <entry>1 hour 30 minutes</entry>
-		  <entry>PT1H30M</entry>
-		 </row>
-		 <row>
-		  <entry>2 years 10 months 15 days 10 hours 30 minutes 20 seconds</entry>
-		  <entry>P2Y10M15DT10H30M20S</entry>
-		 </row>
-		</tbody>
-	   </tgroup>
-	  </table>
     </sect3>
 
     <sect3>
@@ -1990,11 +1941,6 @@ January 8 04:05:06 1999 PST
          <entry>regional style</entry>
          <entry>17.12.1997 07:37:16.00 PST</entry>
         </row>
-	<row>
-	 <entry>ISO8601basic</entry>
-	 <entry>ISO 8601 basic format</entry>
-	 <entry>19971217T073716-08</entry>
-	</row>
        </tbody>
       </tgroup>
      </table>
@@ -2051,11 +1997,6 @@ January 8 04:05:06 1999 PST
 </programlisting>
     </para>
 
-    <para>
-	 If the <varname>datestyle</> is set to iso8601basic, the interval
-	 output is a ISO-8601 time interval with time-unit designator (like P1Y6M or PT23H59M59S).
-    </para>
-
     <para>
      The date/time styles can be selected by the user using the
      <command>SET datestyle</command> command, the

src/backend/commands/variable.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.91 2003/12/20 15:32:54 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/variable.c,v 1.92 2003/12/21 04:34:35 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -82,12 +82,7 @@ assign_datestyle(const char *value, bool doit, bool interactive)
 
 		/* Ugh. Somebody ought to write a table driven version -- mjl */
 
-		if (strcasecmp(tok, "ISO8601BASIC") == 0)
-		{
-			newDateStyle = USE_ISO8601BASIC_DATES;
-			scnt++;
-		}
-		else if (strcasecmp(tok, "ISO") == 0)
+		if (strcasecmp(tok, "ISO") == 0)
 		{
 			newDateStyle = USE_ISO_DATES;
 			scnt++;
@@ -203,9 +198,6 @@ assign_datestyle(const char *value, bool doit, bool interactive)
 		case USE_ISO_DATES:
 			strcpy(result, "ISO");
 			break;
-		case USE_ISO8601BASIC_DATES:
-			strcpy(result, "ISO8601BASIC");
-			break;
 		case USE_SQL_DATES:
 			strcpy(result, "SQL");
 			break;