Please find attached a patch (diff -c against cvs HEAD) to add a

function that accepts a double precision argument assumed to be a Unix
epoch timestamp and returns timestamp with time zone, and accompanying
documentation.

Usage:

test=# select to_timestamp(200120400);
       to_timestamp
------------------------
  1976-05-05 14:00:00+09
(1 row)

Michael Glaesemann

doc/src/sgml/func.sgml

 <!--
-$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.252 2005/06/07 07:08:34 neilc Exp $
+$PostgreSQL: pgsql/doc/src/sgml/func.sgml,v 1.253 2005/06/09 16:35:08 momjian Exp $
 PostgreSQL documentation
 -->
 
@@ -4082,6 +4082,13 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
     argument is the value to be formatted and the second argument is a
     template that defines the output or input format.
    </para>
+   <para>
+    The <function>to_timestamp</function> function can also take a single 
+    <type>double precision</type> argument to convert from Unix epoch to 
+    <type>timestamp with time zone</type>.
+    (<type>Integer</type> Unix epochs are implicitly cast to 
+    <type>double precision</type>.)
+   </para>
 
     <table id="functions-formatting-table">
      <title>Formatting Functions</title>
@@ -4138,6 +4145,12 @@ SELECT SUBSTRING('XY1234Z', 'Y*?([0-9]{1,3})');
         <entry>convert string to time stamp</entry>
         <entry><literal>to_timestamp('05&nbsp;Dec&nbsp;2000', 'DD&nbsp;Mon&nbsp;YYYY')</literal></entry>
        </row>
+       <row>
+        <entry><literal><function>to_timestamp</function>(<type>double precision</type>)</literal></entry>
+        <entry><type>timestamp with time zone</type></entry>
+        <entry>convert UNIX epoch to time stamp</entry>
+        <entry><literal>to_timestamp(200120400)</literal></entry>
+       </row>
        <row>
         <entry><literal><function>to_number</function>(<type>text</type>, <type>text</type>)</literal></entry>
         <entry><type>numeric</type></entry>

src/include/catalog/pg_proc.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.364 2005/06/07 07:08:34 neilc Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.365 2005/06/09 16:35:09 momjian Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -1459,6 +1459,8 @@ DATA(insert OID = 1156 (  timestamptz_ge   PGNSP PGUID 12 f f t f i 2 16 "1184 1
 DESCR("greater-than-or-equal");
 DATA(insert OID = 1157 (  timestamptz_gt   PGNSP PGUID 12 f f t f i 2 16 "1184 1184" _null_ _null_ _null_ timestamp_gt - _null_ ));
 DESCR("greater-than");
+DATA(insert OID = 1158 (  to_timestamp	   PGNSP PGUID 14 f f t f i 1 1184 "701" _null_	_null_ _null_ "select (\'epoch\'::timestamptz + $1 * \'1 second\'::interval)" - _null_ ));
+DESCR("convert UNIX epoch to timestamptz");
 DATA(insert OID = 1159 (  timezone		   PGNSP PGUID 12 f f t f i 2 1114 "25 1184" _null_ _null_ _null_  timestamptz_zone - _null_ ));
 DESCR("adjust timestamp to new time zone");