diff --git a/storage/innobase/dict/dict0mem.cc b/storage/innobase/dict/dict0mem.cc
index 4d21f90fa97..f5f61eff5b3 100644
--- a/storage/innobase/dict/dict0mem.cc
+++ b/storage/innobase/dict/dict0mem.cc
@@ -1216,10 +1216,10 @@ inline void dict_index_t::reconstruct_fields()
 	n_nullable = 0;
 	ulint n_core_null = 0;
 	const bool comp = dict_table_is_comp(table);
-	const unsigned* non_pk_col_map = table->instant->non_pk_col_map;
+	const auto* non_pk_col_map = table->instant->non_pk_col_map;
 	for (unsigned i = n_first, o = i, j = 0; i < n_fields; ) {
 		dict_field_t& f = tfields[i++];
-		unsigned c = *non_pk_col_map++;
+		auto c = *non_pk_col_map++;
 		if (c & 1U << 15) {
 			f.col = &table->instant->dropped[j++];
 			ut_ad(f.col->is_dropped());
@@ -1241,32 +1241,6 @@ inline void dict_index_t::reconstruct_fields()
 	n_core_null_bytes = UT_BITS_IN_BYTES(n_core_null);
 }
 
-/** Serialise metadata of dropped or reordered columns.
-@param[in,out]	heap	memory heap for allocation
-@param[out]	field	data field with the metadata */
-void dict_table_t::serialise_columns(mem_heap_t* heap, dfield_t* field) const
-{
-	DBUG_ASSERT(instant);
-	const dict_index_t& index = *UT_LIST_GET_FIRST(indexes);
-	unsigned n_fixed = index.first_user_field();
-	unsigned num_non_pk_fields = index.n_fields - n_fixed;
-
-	ulint len = 4 + num_non_pk_fields * 2;
-
-	byte* data = static_cast<byte*>(mem_heap_alloc(heap, len));
-
-	dfield_set_data(field, data, len);
-
-	mach_write_to_4(data, num_non_pk_fields);
-
-	data += 4;
-
-	for (ulint i = n_fixed; i < index.n_fields; i++) {
-		mach_write_to_2(data, instant->non_pk_col_map[i - n_fixed]);
-		data += 2;
-	}
-}
-
 /** Reconstruct dropped or reordered columns.
 @param[in]	metadata	data from serialise_columns()
 @param[in]	len		length of the metadata, in bytes
@@ -1289,7 +1263,7 @@ bool dict_table_t::deserialise_columns(const byte* metadata, ulint len)
 		return true;
 	}
 
-	unsigned* non_pk_col_map = static_cast<unsigned*>(
+	uint16_t* non_pk_col_map = static_cast<uint16_t*>(
 		mem_heap_alloc(heap,
 			       num_non_pk_fields * sizeof *non_pk_col_map));
 
@@ -1320,7 +1294,7 @@ bool dict_table_t::deserialise_columns(const byte* metadata, ulint len)
 	dict_col_t* col = dropped_cols;
 	for (unsigned i = 0; i < num_non_pk_fields; i++) {
 		if (non_pk_col_map[i] & 1U << 15) {
-			unsigned fixed_len = non_pk_col_map[i] & ~(3U << 14);
+			auto fixed_len = non_pk_col_map[i] & ~(3U << 14);
 			DBUG_ASSERT(fixed_len <= DICT_MAX_FIXED_COL_LEN + 1);
 			(col++)->set_dropped(non_pk_col_map[i] & 1U << 14,
 					     fixed_len == 1,
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index f0e31545154..fdfb9192cfd 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -487,7 +487,7 @@ inline void dict_table_t::instant_column(const dict_table_t& table,
 
 	if (instant || table.instant) {
 		const unsigned u = index->first_user_field();
-		unsigned* non_pk_col_map = static_cast<unsigned*>(
+		uint16_t* non_pk_col_map = static_cast<uint16_t*>(
 			mem_heap_alloc(heap, (index->n_fields - u)
 				       * sizeof *non_pk_col_map));
 		/* FIXME: add instant->heap, and transfer ownership here */
@@ -524,9 +524,9 @@ dup_dropped:
 			ulint fixed_len = dict_col_get_fixed_size(
 				field->col, flags & DICT_TF_COMPACT);
 			*non_pk_col_map++ = 1U << 15
-				| unsigned(!field->col->is_nullable()) << 14
+				| uint16_t(!field->col->is_nullable()) << 14
 				| (fixed_len
-				   ? unsigned(fixed_len + 1)
+				   ? uint16_t(fixed_len + 1)
 				   : field->col->len > 255);
 			ut_ad(field->col >= table.instant->dropped);
 			ut_ad(field->col < table.instant->dropped
@@ -5110,6 +5110,33 @@ innobase_drop_virtual_try(
 	return false;
 }
 
+/** Serialise metadata of dropped or reordered columns.
+@param[in,out]	heap	memory heap for allocation
+@param[out]	field	data field with the metadata */
+inline
+void dict_table_t::serialise_columns(mem_heap_t* heap, dfield_t* field) const
+{
+	DBUG_ASSERT(instant);
+	const dict_index_t& index = *UT_LIST_GET_FIRST(indexes);
+	unsigned n_fixed = index.first_user_field();
+	unsigned num_non_pk_fields = index.n_fields - n_fixed;
+
+	ulint len = 4 + num_non_pk_fields * 2;
+
+	byte* data = static_cast<byte*>(mem_heap_alloc(heap, len));
+
+	dfield_set_data(field, data, len);
+
+	mach_write_to_4(data, num_non_pk_fields);
+
+	data += 4;
+
+	for (ulint i = n_fixed; i < index.n_fields; i++) {
+		mach_write_to_2(data, instant->non_pk_col_map[i - n_fixed]);
+		data += 2;
+	}
+}
+
 /** Construct the metadata record for instant ALTER TABLE.
 @param[in]	row	dummy or default values for existing columns
 @param[in,out]	heap	memory heap for allocations
diff --git a/storage/innobase/include/dict0mem.h b/storage/innobase/include/dict0mem.h
index b4823ee6a94..1521fb74970 100644
--- a/storage/innobase/include/dict0mem.h
+++ b/storage/innobase/include/dict0mem.h
@@ -1513,7 +1513,7 @@ struct dict_instant_t
 	/** Dropped columns */
 	dict_col_t* dropped;
 	/** Mapping the non-pk field to column of the table. */
-	unsigned* non_pk_col_map;
+	uint16_t* non_pk_col_map;
 };
 
 /** These are used when MySQL FRM and InnoDB data dictionary are
@@ -1606,7 +1606,7 @@ struct dict_table_t {
 	/** Serialise metadata of dropped or reordered columns.
 	@param[in,out]	heap	memory heap for allocation
 	@param[out]	field	data field with the metadata */
-	void serialise_columns(mem_heap_t* heap, dfield_t* field) const;
+	inline void serialise_columns(mem_heap_t* heap, dfield_t* field) const;
 
 	/** Reconstruct dropped or reordered columns.
 	@param[in]	metadata	data from serialise_columns()