Merge mysql-5.1 to mysql-5.5.

storage/innobase/btr/btr0cur.c

@@ -3542,16 +3542,11 @@ btr_record_not_null_field_in_rec(
 	}
 
 	for (i = 0; i < n_unique; i++) {
-		ulint	rec_len;
-
-		rec_get_nth_field_offs(offsets, i, &rec_len);
-
-		if (rec_len != UNIV_SQL_NULL) {
-			n_not_null[i]++;
-		} else {
-			/* Break if we hit the first NULL value */
+		if (rec_offs_nth_sql_null(offsets, i)) {
 			break;
 		}
+
+		n_not_null[i]++;
 	}
 }
 
@@ -3694,8 +3689,7 @@ btr_estimate_number_of_different_key_vals(
 
 			if (n_not_null) {
 				btr_record_not_null_field_in_rec(
-					n_cols, offsets_next_rec,
-					n_not_null);
+					n_cols, offsets_next_rec, n_not_null);
 			}
 
 			total_external_size