*** a/doc/src/sgml/array.sgml
--- b/doc/src/sgml/array.sgml
***************
*** 338,343 **** SELECT array_length(schedule, 1) FROM sal_emp WHERE name = 'Carol';
--- 338,356 ----
              2
  (1 row)
  </programlisting>
+ 
+  <function>cardinality</function> returns the total number of elements in an
+  array across all dimensions.  It is effectively the number of rows a call to
+  <function>unnest</function> would yield:
+ 
+ <programlisting>
+ SELECT cardinality(schedule) FROM sal_emp WHERE name = 'Carol';
+ 
+  cardinality 
+ -------------
+            4
+ (1 row)
+ </programlisting>
   </para>
   </sect2>
  
*** a/doc/src/sgml/func.sgml
--- b/doc/src/sgml/func.sgml
***************
*** 11009,11014 **** SELECT NULLIF(value, '(none)') ...
--- 11009,11017 ----
      <primary>array_upper</primary>
    </indexterm>
    <indexterm>
+     <primary>cardinality</primary>
+   </indexterm>
+   <indexterm>
      <primary>string_to_array</primary>
    </indexterm>
    <indexterm>
***************
*** 11167,11172 **** SELECT NULLIF(value, '(none)') ...
--- 11170,11186 ----
         <row>
          <entry>
           <literal>
+           <function>cardinality</function>(<type>anyarray</type>)
+          </literal>
+         </entry>
+         <entry><type>int</type></entry>
+         <entry>returns the total number of elements in the array, or 0 if the array is empty</entry>
+         <entry><literal>cardinality(ARRAY[[1,2],[3,4]])</literal></entry>
+         <entry><literal>4</literal></entry>
+        </row>
+        <row>
+         <entry>
+          <literal>
            <function>string_to_array</function>(<type>text</type>, <type>text</type> <optional>, <type>text</type></optional>)
           </literal>
          </entry>
*** a/src/backend/utils/adt/arrayfuncs.c
--- b/src/backend/utils/adt/arrayfuncs.c
***************
*** 1740,1745 **** array_length(PG_FUNCTION_ARGS)
--- 1740,1766 ----
  }
  
  /*
+  * array_cardinality:
+  *		returns the total number of elements in an array
+  */
+ Datum
+ array_cardinality(PG_FUNCTION_ARGS)
+ {
+ 	ArrayType  *v = PG_GETARG_ARRAYTYPE_P(0);
+ 	int		   *dimv;
+ 	int			i;
+ 	int			cardinality;
+ 
+ 	dimv = ARR_DIMS(v);
+ 	cardinality = 1;
+ 	for (i = 0; i < ARR_NDIM(v); i++)
+ 		cardinality *= dimv[i];
+ 
+ 	PG_RETURN_INT32(cardinality);
+ }
+ 
+ 
+ /*
   * array_ref :
   *	  This routine takes an array pointer and a subscript array and returns
   *	  the referenced item as a Datum.  Note that for a pass-by-reference
*** a/src/include/catalog/pg_proc.h
--- b/src/include/catalog/pg_proc.h
***************
*** 840,845 **** DATA(insert OID = 2092 (  array_upper	   PGNSP PGUID 12 1 0 0 0 f f f f t f i 2
--- 840,847 ----
  DESCR("array upper dimension");
  DATA(insert OID = 2176 (  array_length	   PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 23 "2277 23" _null_ _null_ _null_ _null_ array_length _null_ _null_ _null_ ));
  DESCR("array length");
+ DATA(insert OID = 3179 (  cardinality	   PGNSP PGUID 12 1 0 0 0 f f f f t f i 1 0 23 "2277" _null_ _null_ _null_ _null_ array_cardinality _null_ _null_ _null_ ));
+ DESCR("array cardinality");
  DATA(insert OID = 378 (  array_append	   PGNSP PGUID 12 1 0 0 0 f f f f f f i 2 0 2277 "2277 2283" _null_ _null_ _null_ _null_ array_push _null_ _null_ _null_ ));
  DESCR("append element onto end of array");
  DATA(insert OID = 379 (  array_prepend	   PGNSP PGUID 12 1 0 0 0 f f f f f f i 2 0 2277 "2283 2277" _null_ _null_ _null_ _null_ array_push _null_ _null_ _null_ ));
*** a/src/include/utils/array.h
--- b/src/include/utils/array.h
***************
*** 204,209 **** extern Datum array_dims(PG_FUNCTION_ARGS);
--- 204,210 ----
  extern Datum array_lower(PG_FUNCTION_ARGS);
  extern Datum array_upper(PG_FUNCTION_ARGS);
  extern Datum array_length(PG_FUNCTION_ARGS);
+ extern Datum array_cardinality(PG_FUNCTION_ARGS);
  extern Datum array_larger(PG_FUNCTION_ARGS);
  extern Datum array_smaller(PG_FUNCTION_ARGS);
  extern Datum generate_subscripts(PG_FUNCTION_ARGS);
*** a/src/test/regress/expected/arrays.out
--- b/src/test/regress/expected/arrays.out
***************
*** 1455,1460 **** select array_length(array[[1,2,3], [4,5,6]], 3);
--- 1455,1502 ----
               
  (1 row)
  
+ select cardinality(NULL::int[]);
+  cardinality 
+ -------------
+             
+ (1 row)
+ 
+ select cardinality('{}'::int[]);
+  cardinality 
+ -------------
+            1
+ (1 row)
+ 
+ select cardinality(array[1,2,3]);
+  cardinality 
+ -------------
+            3
+ (1 row)
+ 
+ select cardinality('[2:4]={5,6,7}'::int[]);
+  cardinality 
+ -------------
+            3
+ (1 row)
+ 
+ select cardinality('{{1,2}}'::int[]);
+  cardinality 
+ -------------
+            2
+ (1 row)
+ 
+ select cardinality('{{1,2},{3,4},{5,6}}'::int[]);
+  cardinality 
+ -------------
+            6
+ (1 row)
+ 
+ select cardinality('{{{1}},{{2,3},{3,4}}}'::int[]);
+  cardinality 
+ -------------
+            8
+ (1 row)
+ 
  select array_agg(unique1) from (select unique1 from tenk1 where unique1 < 15 order by unique1) ss;
                array_agg               
  --------------------------------------
*** a/src/test/regress/sql/arrays.sql
--- b/src/test/regress/sql/arrays.sql
***************
*** 419,424 **** select array_length(array[[1,2,3], [4,5,6]], 1);
--- 419,432 ----
  select array_length(array[[1,2,3], [4,5,6]], 2);
  select array_length(array[[1,2,3], [4,5,6]], 3);
  
+ select cardinality(NULL::int[]);
+ select cardinality('{}'::int[]);
+ select cardinality(array[1,2,3]);
+ select cardinality('[2:4]={5,6,7}'::int[]);
+ select cardinality('{{1,2}}'::int[]);
+ select cardinality('{{1,2},{3,4},{5,6}}'::int[]);
+ select cardinality('{{{1}},{{2,3},{3,4}}}'::int[]);
+ 
  select array_agg(unique1) from (select unique1 from tenk1 where unique1 < 15 order by unique1) ss;
  select array_agg(ten) from (select ten from tenk1 where unique1 < 15 order by unique1) ss;
  select array_agg(nullif(ten, 4)) from (select ten from tenk1 where unique1 < 15 order by unique1) ss;