*** a/src/backend/utils/adt/misc.c
--- b/src/backend/utils/adt/misc.c
***************
*** 45,50 ****
--- 45,119 ----
  
  
  /*
+  * count_nulls()
+  *  Count the number of NULL input arguments
+  */
+ Datum
+ pg_count_nulls(PG_FUNCTION_ARGS)
+ {
+ 	int32 count = 0;
+ 	int i;
+ 
+ 	if (get_fn_expr_variadic(fcinfo->flinfo))
+ 	{
+ 		ArrayType  *arr;
+ 		int ndims, nitems, *dims;
+ 		bits8 *bitmap;
+ 		int bitmask;
+ 
+ 		/* Should have just the one argument */
+ 		Assert(PG_NARGS() == 1);
+ 
+ 		/* count_nulls(VARIADIC NULL) is defined as NULL */
+ 		if (PG_ARGISNULL(0))
+ 			PG_RETURN_NULL();
+ 
+ 		/*
+ 		 * Non-null argument had better be an array.  We assume that any call
+ 		 * context that could let get_fn_expr_variadic return true will have
+ 		 * checked that a VARIADIC-labeled parameter actually is an array.  So
+ 		 * it should be okay to just Assert that it's an array rather than
+ 		 * doing a full-fledged error check.
+ 		 */
+ 		Assert(OidIsValid(get_base_element_type(get_fn_expr_argtype(fcinfo->flinfo, 0))));
+ 
+ 		/* OK, safe to fetch the array value */
+ 		arr = PG_GETARG_ARRAYTYPE_P(0);
+ 
+ 		ndims = ARR_NDIM(arr);
+ 		dims = ARR_DIMS(arr);
+ 		nitems = ArrayGetNItems(ndims, dims);
+ 		//if (nitems == 0)
+ 		//	return PG_RETURN_INT32(0);
+ 
+ 		bitmap = ARR_NULLBITMAP(arr);
+ 		if (!bitmap)
+ 			PG_RETURN_INT32(0);
+ 
+ 		for (i = 0; i < nitems; i++)
+ 		{
+ 			if ((*bitmap & bitmask) == 0)
+ 				count++;
+ 
+ 			bitmask <<= 1;
+ 			if (bitmask == 0x100)
+ 			{
+ 				bitmap++;
+ 				bitmask = 1;
+ 			}
+ 		}
+ 		PG_RETURN_INT32(count);
+ 	}
+ 
+ 	for (i = 0; i < PG_NARGS(); i++)
+ 	{
+ 		if (PG_ARGISNULL(i))
+ 			count++;
+ 	}
+ 	PG_RETURN_INT32(count);
+ }
+ 
+ /*
   * current_database()
   *	Expose the current database to the user
   */
*** a/src/include/catalog/pg_proc.h
--- b/src/include/catalog/pg_proc.h
***************
*** 2959,2964 **** DESCR("adjust time with time zone precision");
--- 2959,2965 ----
  
  DATA(insert OID = 2003 (  textanycat	   PGNSP PGUID 14 1 0 0 0 f f f f t f s 2 0 25 "25 2776" _null_ _null_ _null_ _null_ _null_ "select $1 || $2::pg_catalog.text" _null_ _null_ _null_ ));
  DATA(insert OID = 2004 (  anytextcat	   PGNSP PGUID 14 1 0 0 0 f f f f t f s 2 0 25 "2776 25" _null_ _null_ _null_ _null_ _null_ "select $1::pg_catalog.text || $2" _null_ _null_ _null_ ));
+ DATA(insert OID = 3308 (  count_nulls	   PGNSP PGUID 12 1 0 2276 0 f f f f f f i 1 0 23 "2276" "{2276}" "{v}" _null_ _null_ _null_	pg_count_nulls _null_ _null_ _null_ ));
  
  DATA(insert OID = 2005 (  bytealike		   PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 16 "17 17" _null_ _null_ _null_ _null_ _null_ bytealike _null_ _null_ _null_ ));
  DATA(insert OID = 2006 (  byteanlike	   PGNSP PGUID 12 1 0 0 0 f f f f t f i 2 0 16 "17 17" _null_ _null_ _null_ _null_ _null_ byteanlike _null_ _null_ _null_ ));
*** a/src/include/utils/builtins.h
--- b/src/include/utils/builtins.h
***************
*** 481,486 **** extern Datum pg_ls_dir(PG_FUNCTION_ARGS);
--- 481,487 ----
  extern Datum pg_ls_dir_1arg(PG_FUNCTION_ARGS);
  
  /* misc.c */
+ extern Datum pg_count_nulls(PG_FUNCTION_ARGS);
  extern Datum current_database(PG_FUNCTION_ARGS);
  extern Datum current_query(PG_FUNCTION_ARGS);
  extern Datum pg_cancel_backend(PG_FUNCTION_ARGS);