Clean up the update code

row_upd_changes_field_size_or_external(): Revert some unnecessary
changes, and assert that the update vector does not contain the
magic value UNIV_SQL_DEFAULT.

row_upd_rec_in_place(): Remove a redundant assertion.
rec_set_nth_field() already asserts the same.

row_upd_build_sec_rec_difference_binary(): Assert that there are
no default values in a secondary index tuple.

storage/innobase/include/data0data.ic

@@ -328,6 +328,7 @@ dfield_data_is_binary_equal(
 	ulint		len,	/*!< in: data length or UNIV_SQL_NULL */
 	const byte*	data)	/*!< in: data */
 {
+	ut_ad(len != UNIV_SQL_DEFAULT);
 	return(len == dfield_get_len(field)
 	       && (len == UNIV_SQL_NULL
 		   || !memcmp(dfield_get_data(field), data, len)));

storage/innobase/include/rem0rec.ic

@@ -1224,6 +1224,7 @@ rec_set_nth_field(
 
 	ut_ad(rec);
 	ut_ad(rec_offs_validate(rec, NULL, offsets));
+	ut_ad(!rec_offs_nth_default(offsets, n));
 
 	if (len == UNIV_SQL_NULL) {
 		if (!rec_offs_nth_sql_null(offsets, n)) {
@@ -1234,7 +1235,6 @@ rec_set_nth_field(
 		return;
 	}
 
-	ut_ad(!rec_offs_nth_default(offsets, n));
 	data2 = (byte*)rec_get_nth_field(rec, offsets, n, &len2);
 	if (len2 == UNIV_SQL_NULL) {
 		ut_ad(!rec_offs_comp(offsets));

storage/innobase/row/row0upd.cc

@@ -563,9 +563,9 @@ row_upd_index_entry_sys_field(
 
 /***********************************************************//**
 Returns TRUE if row update changes size of some field in index or if some
-field to be updated is stored externally in rec or added columns or update.
+field to be updated is stored externally in rec or update.
 @return TRUE if the update changes the size of some field in index or
-the field is external in rec or added columns or update */
+the field is external in rec or update */
 ibool
 row_upd_changes_field_size_or_external(
 /*===================================*/
@@ -595,6 +595,7 @@ row_upd_changes_field_size_or_external(
 
 		new_val = &(upd_field->new_val);
 		new_len = dfield_get_len(new_val);
+		ut_ad(new_len != UNIV_SQL_DEFAULT);
 
 		if (dfield_is_null(new_val) && !rec_offs_comp(offsets)) {
 			/* A bug fixed on Dec 31st, 2004: we looked at the
@@ -610,8 +611,8 @@ row_upd_changes_field_size_or_external(
 
 		old_len = rec_offs_nth_size(offsets, upd_field->field_no);
 
-		if (rec_offs_comp(offsets)){
-		 	if(rec_offs_nth_sql_null(offsets,
+		if (rec_offs_comp(offsets)
+		    && rec_offs_nth_sql_null(offsets,
 					     upd_field->field_no)) {
 			/* Note that in the compact table format, for a
 			variable length field, an SQL NULL will use zero
@@ -621,14 +622,11 @@ row_upd_changes_field_size_or_external(
 			if we update an SQL NULL varchar to an empty string! */
 
 			old_len = UNIV_SQL_NULL;
-			} else if (rec_offs_nth_default(offsets, upd_field->field_no)) {
-				/* If update the added columns, use pessimistic update */
-				old_len = UNIV_SQL_DEFAULT;
-			}
 		}
 
 		if (dfield_is_ext(new_val) || old_len != new_len
 		    || rec_offs_nth_extern(offsets, upd_field->field_no)) {
+
 			return(TRUE);
 		}
 	}
@@ -734,10 +732,6 @@ row_upd_rec_in_place(
 		ut_ad(!dfield_is_ext(new_val) ==
 		      !rec_offs_nth_extern(offsets, upd_field->field_no));
 
-		/* If the added columns is been updated, it always use 
-		pessimistic update. So we assert here. Detailed in 
-		row_upd_changes_field_size_or_external() */
-		ut_ad(!rec_offs_nth_default(offsets, upd_field->field_no));
 		rec_set_nth_field(rec, offsets, upd_field->field_no,
 				  dfield_get_data(new_val),
 				  dfield_get_len(new_val));
@@ -999,6 +993,7 @@ row_upd_build_sec_rec_difference_binary(
 	ut_ad(rec_offs_validate(rec, index, offsets));
 	ut_ad(rec_offs_n_fields(offsets) == dtuple_get_n_fields(entry));
 	ut_ad(!rec_offs_any_extern(offsets));
+	ut_ad(!rec_offs_any_default(offsets));
 
 	update = upd_create(dtuple_get_n_fields(entry), heap);
 
@@ -1006,9 +1001,6 @@ row_upd_build_sec_rec_difference_binary(
 
 	for (i = 0; i < dtuple_get_n_fields(entry); i++) {
 
-		/* There is no default value added column 
-		   in secondary index */
-		ut_ad(!rec_offs_nth_default(offsets, i));
 		data = rec_get_nth_field(rec, offsets, i, &len);
 
 		dfield = dtuple_get_nth_field(entry, i);