*** a/doc/src/sgml/func.sgml
--- b/doc/src/sgml/func.sgml
***************
*** 8693,8698 **** SELECT xpath('//mydefns:b/text()', '<a xmlns="http://example.com"><b>test</b></a
--- 8693,8731 ----
  (1 row)
  ]]></screen>
     </para>
+ 
+    <sect3>
+     <title>xpath_exists</title>
+ 
+     <indexterm>
+      <primary>xpath_exists</primary>
+     </indexterm>
+ 
+     <synopsis>
+      <function>xpath_exists</function>(<replaceable>xpath</replaceable>, <replaceable>xml</replaceable><optional>, <replaceable>nsarray</replaceable></optional>)
+     </synopsis>
+ 
+     <para>
+      The function <function>xpath_exists</function> is a specialised form
+      of the <function>xpath</function> function. Though the functions are
+      syntactically the same the xpath expressions are evaluated in differing
+      contexts. Instead of returning the XML values that satisfy the xpath, this
+      function returns a boolean indicating whether the query was satisfied or not.
+     </para>
+ 
+     <para>
+      Example:
+      <screen><![CDATA[
+ SELECT xpath_exists('/my:a/text()', '<my:a xmlns:my="http://example.com">test</my:a>', 
+                      ARRAY[ARRAY['my', 'http://example.com']]);
+ 
+  xpath_exists  
+ ------------
+  t
+ (1 row)
+ ]]></screen>
+      </para>
+     </sect3>
    </sect2>

    <sect2 id="functions-xml-mapping">
*** a/src/backend/utils/adt/xml.c
--- b/src/backend/utils/adt/xml.c
***************
*** 3541,3543 **** Datum xmlexists(PG_FUNCTION_ARGS)
--- 3541,3567 ----
  	return 0;
  #endif
  }
+ 
+ /*
+  * Determines if the node specified by the supplied XPath exists
+  * in a given XML document, returning a boolean. Differs from
+  * xmlexists as it supports namespaces and is not defined in SQL/XML.
+  */
+ Datum
+ xpath_exists(PG_FUNCTION_ARGS)
+ {
+ #ifdef USE_LIBXML
+ 	text	   *xpath_expr_text = PG_GETARG_TEXT_P(0);
+ 	xmltype    *data = PG_GETARG_XML_P(1);
+ 	ArrayType  *namespaces = PG_GETARG_ARRAYTYPE_P(2);
+ 	int			res_nitems;
+ 
+ 	xpath_internal(xpath_expr_text, data, namespaces,
+ 				   &res_nitems, NULL);
+ 
+ 	PG_RETURN_BOOL(res_nitems > 0);
+ #else
+ 	NO_XML_SUPPORT();
+ 	return 0;
+ #endif
+ }
*** a/src/include/catalog/pg_proc.h
--- b/src/include/catalog/pg_proc.h
***************
*** 4390,4395 **** DESCR("evaluate XPath expression");
--- 4390,4400 ----
  DATA(insert OID = 2614 (  xmlexists	 PGNSP PGUID 12 1 0 0 f f f t f i 2 0 16 "25 142" _null_ _null_ _null_ _null_ xmlexists _null_ _null_ _null_ ));
  DESCR("test XML value against XPath expression");

+ DATA(insert OID = 3037 (  xpath_exists	 PGNSP PGUID 12 1 0 0 f f f t f i 3 0 16 "25 142 1009" _null_ _null_ _null_ _null_ xpath_exists _null_ _null_ _null_ ));
+ DESCR("evaluate XPath expression in a boolean context, with namespaces support");
+ DATA(insert OID = 3038 (  xpath_exists	 PGNSP PGUID 14 1 0 0 f f f t f i 2 0 16 "25 142" _null_ _null_ _null_ _null_ "select pg_catalog.xpath_exists($1, $2, ''{}''::pg_catalog.text[])" _null_ _null_ _null_ ));
+ DESCR("evaluate XPath expression in a boolean context");
+ 
  /* uuid */
  DATA(insert OID = 2952 (  uuid_in		   PGNSP PGUID 12 1 0 0 f f f t f i 1 0 2950 "2275" _null_ _null_ _null_ _null_ uuid_in _null_ _null_ _null_ ));
  DESCR("I/O");
*** a/src/include/utils/xml.h
--- b/src/include/utils/xml.h
***************
*** 37,42 **** extern Datum texttoxml(PG_FUNCTION_ARGS);
--- 37,43 ----
  extern Datum xmltotext(PG_FUNCTION_ARGS);
  extern Datum xmlvalidate(PG_FUNCTION_ARGS);
  extern Datum xpath(PG_FUNCTION_ARGS);
+ extern Datum xpath_exists(PG_FUNCTION_ARGS);
  extern Datum xmlexists(PG_FUNCTION_ARGS);

  extern Datum table_to_xml(PG_FUNCTION_ARGS);
*** a/src/test/regress/expected/xml.out
--- b/src/test/regress/expected/xml.out
***************
*** 502,507 **** SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');
--- 502,560 ----
   {<b>two</b>,<b>etc</b>}
  (1 row)

+ -- Test xpath_exists evaluation
+ SELECT xpath_exists('//town[text() = ''Toronto'']','<towns><town>Bidford-on-Avon</town><town>Cwmbran</town><town>Bristol</town></towns>'::xml);
+  xpath_exists 
+ --------------
+  f
+ (1 row)
+ 
+ SELECT xpath_exists('//town[text() = ''Cwmbran'']','<towns><town>Bidford-on-Avon</town><town>Cwmbran</town><town>Bristol</town></towns>'::xml);
+  xpath_exists 
+ --------------
+  t
+ (1 row)
+ 
+ INSERT INTO xmltest VALUES (4, '<menu><beers><name>Budvar</name><cost>free</cost><name>Carling</name><cost>lots</cost></beers></menu>'::xml);
+ INSERT INTO xmltest VALUES (5, '<menu><beers><name>Molson</name><cost>free</cost><name>Carling</name><cost>lots</cost></beers></menu>'::xml);
+ INSERT INTO xmltest VALUES (6, '<myns:menu xmlns:myns="http://myns.com"><myns:beers><myns:name>Budvar</myns:name><myns:cost>free</myns:cost><myns:name>Carling</myns:name><myns:cost>lots</myns:cost></myns:beers></myns:menu>'::xml);
+ INSERT INTO xmltest VALUES (7, '<myns:menu xmlns:myns="http://myns.com"><myns:beers><myns:name>Molson</myns:name><myns:cost>free</myns:cost><myns:name>Carling</myns:name><myns:cost>lots</myns:cost></myns:beers></myns:menu>'::xml);
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/menu/beer',data);
+  count 
+ -------
+      0
+ (1 row)
+ 
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/menu/beers',data);
+  count 
+ -------
+      2
+ (1 row)
+ 
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/menu/beers/name[text() = ''Molson'']',data);
+  count 
+ -------
+      1
+ (1 row)
+ 
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/myns:menu/myns:beer',data,ARRAY[ARRAY['myns','http://myns.com']]);
+  count 
+ -------
+      0
+ (1 row)
+ 
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/myns:menu/myns:beers',data,ARRAY[ARRAY['myns','http://myns.com']]);
+  count 
+ -------
+      2
+ (1 row)
+ 
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/myns:menu/myns:beers/myns:name[text() = ''Molson'']',data,ARRAY[ARRAY['myns','http://myns.com']]);
+  count 
+ -------
+      1
+ (1 row)
+ 
  -- Test xmlexists evaluation
  SELECT xmlexists('//town[text() = ''Toronto'']' PASSING BY REF '<towns><town>Bidford-on-Avon</town><town>Cwmbran</town><town>Bristol</town></towns>');
   xmlexists 
***************
*** 515,524 **** SELECT xmlexists('//town[text() = ''Cwmbran'']' PASSING BY REF '<towns><town>Bid
   t
  (1 row)

- INSERT INTO xmltest VALUES (4, '<menu><beers><name>Budvar</name><cost>free</cost><name>Carling</name><cost>lots</cost></beers></menu>'::xml);
- INSERT INTO xmltest VALUES (5, '<menu><beers><name>Molson</name><cost>free</cost><name>Carling</name><cost>lots</cost></beers></menu>'::xml);
- INSERT INTO xmltest VALUES (6, '<myns:menu xmlns:myns="http://myns.com"><myns:beers><myns:name>Budvar</myns:name><myns:cost>free</myns:cost><myns:name>Carling</myns:name><myns:cost>lots</myns:cost></myns:beers></myns:menu>'::xml);
- INSERT INTO xmltest VALUES (7, '<myns:menu xmlns:myns="http://myns.com"><myns:beers><myns:name>Molson</myns:name><myns:cost>free</myns:cost><myns:name>Carling</myns:name><myns:cost>lots</myns:cost></myns:beers></myns:menu>'::xml);
  SELECT COUNT(id) FROM xmltest WHERE xmlexists('/menu/beer' PASSING data);
   count 
  -------
--- 568,573 ----
*** a/src/test/regress/sql/xml.sql
--- b/src/test/regress/sql/xml.sql
***************
*** 164,178 **** SELECT xpath('//text()', '<local:data xmlns:local="http://127.0.0.1"><local:piec
  SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
  SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');

! -- Test xmlexists evaluation
! SELECT xmlexists('//town[text() = ''Toronto'']' PASSING BY REF '<towns><town>Bidford-on-Avon</town><town>Cwmbran</town><town>Bristol</town></towns>');
! SELECT xmlexists('//town[text() = ''Cwmbran'']' PASSING BY REF '<towns><town>Bidford-on-Avon</town><town>Cwmbran</town><town>Bristol</town></towns>');

  INSERT INTO xmltest VALUES (4, '<menu><beers><name>Budvar</name><cost>free</cost><name>Carling</name><cost>lots</cost></beers></menu>'::xml);
  INSERT INTO xmltest VALUES (5, '<menu><beers><name>Molson</name><cost>free</cost><name>Carling</name><cost>lots</cost></beers></menu>'::xml);
  INSERT INTO xmltest VALUES (6, '<myns:menu xmlns:myns="http://myns.com"><myns:beers><myns:name>Budvar</myns:name><myns:cost>free</myns:cost><myns:name>Carling</myns:name><myns:cost>lots</myns:cost></myns:beers></myns:menu>'::xml);
  INSERT INTO xmltest VALUES (7, '<myns:menu xmlns:myns="http://myns.com"><myns:beers><myns:name>Molson</myns:name><myns:cost>free</myns:cost><myns:name>Carling</myns:name><myns:cost>lots</myns:cost></myns:beers></myns:menu>'::xml);

  SELECT COUNT(id) FROM xmltest WHERE xmlexists('/menu/beer' PASSING data);
  SELECT COUNT(id) FROM xmltest WHERE xmlexists('/menu/beer' PASSING BY REF data BY REF);
--- 164,188 ----
  SELECT xpath('//loc:piece/@id', '<local:data xmlns:local="http://127.0.0.1"><local:piece id="1">number one</local:piece><local:piece id="2" /></local:data>', ARRAY[ARRAY['loc', 'http://127.0.0.1']]);
  SELECT xpath('//b', '<a>one <b>two</b> three <b>etc</b></a>');

! -- Test xpath_exists evaluation
! SELECT xpath_exists('//town[text() = ''Toronto'']','<towns><town>Bidford-on-Avon</town><town>Cwmbran</town><town>Bristol</town></towns>'::xml);
! SELECT xpath_exists('//town[text() = ''Cwmbran'']','<towns><town>Bidford-on-Avon</town><town>Cwmbran</town><town>Bristol</town></towns>'::xml);

  INSERT INTO xmltest VALUES (4, '<menu><beers><name>Budvar</name><cost>free</cost><name>Carling</name><cost>lots</cost></beers></menu>'::xml);
  INSERT INTO xmltest VALUES (5, '<menu><beers><name>Molson</name><cost>free</cost><name>Carling</name><cost>lots</cost></beers></menu>'::xml);
  INSERT INTO xmltest VALUES (6, '<myns:menu xmlns:myns="http://myns.com"><myns:beers><myns:name>Budvar</myns:name><myns:cost>free</myns:cost><myns:name>Carling</myns:name><myns:cost>lots</myns:cost></myns:beers></myns:menu>'::xml);
  INSERT INTO xmltest VALUES (7, '<myns:menu xmlns:myns="http://myns.com"><myns:beers><myns:name>Molson</myns:name><myns:cost>free</myns:cost><myns:name>Carling</myns:name><myns:cost>lots</myns:cost></myns:beers></myns:menu>'::xml);

+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/menu/beer',data);
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/menu/beers',data);
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/menu/beers/name[text() = ''Molson'']',data);
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/myns:menu/myns:beer',data,ARRAY[ARRAY['myns','http://myns.com']]);
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/myns:menu/myns:beers',data,ARRAY[ARRAY['myns','http://myns.com']]);
+ SELECT COUNT(id) FROM xmltest WHERE xpath_exists('/myns:menu/myns:beers/myns:name[text() = ''Molson'']',data,ARRAY[ARRAY['myns','http://myns.com']]);
+ 
+ -- Test xmlexists evaluation
+ SELECT xmlexists('//town[text() = ''Toronto'']' PASSING BY REF '<towns><town>Bidford-on-Avon</town><town>Cwmbran</town><town>Bristol</town></towns>');
+ SELECT xmlexists('//town[text() = ''Cwmbran'']' PASSING BY REF '<towns><town>Bidford-on-Avon</town><town>Cwmbran</town><town>Bristol</town></towns>');

  SELECT COUNT(id) FROM xmltest WHERE xmlexists('/menu/beer' PASSING data);
  SELECT COUNT(id) FROM xmltest WHERE xmlexists('/menu/beer' PASSING BY REF data BY REF);