MDEV-19606: dict_v_col_t: Encapsulate v_indexes

Remove the separate allocation and pointer indirection of
dict_v_col_t::v_indexes.

storage/innobase/dict/dict0dict.cc

@@ -2496,19 +2496,9 @@ dict_index_add_col(
 
 	if (col->is_virtual()) {
 		dict_v_col_t*	v_col = reinterpret_cast<dict_v_col_t*>(col);
-
-		/* When v_col->v_indexes==NULL,
-		ha_innobase::commit_inplace_alter_table(commit=true)
-		will evict and reload the table definition, and
-		v_col->v_indexes will not be NULL for the new table. */
-		if (v_col->v_indexes != NULL) {
-			/* Register the index with the virtual column index
-			list */
-			v_col->n_v_indexes++;
-			v_col->v_indexes->push_front(
-				dict_v_idx_t(index, index->n_def));
-		}
-
+		/* Register the index with the virtual column index list */
+		v_col->n_v_indexes++;
+		v_col->v_indexes.push_front(dict_v_idx_t(index, index->n_def));
 		col_name = dict_table_get_v_col_name_mysql(
 			table, dict_col_get_no(col));
 	} else {

storage/innobase/dict/dict0mem.cc

@@ -167,6 +167,9 @@ dict_mem_table_create(
 		mem_heap_alloc(heap, table->n_cols * sizeof(dict_col_t)));
 	table->v_cols = static_cast<dict_v_col_t*>(
 		mem_heap_alloc(heap, n_v_cols * sizeof(*table->v_cols)));
+	for (ulint i = n_v_cols; i--; ) {
+		new (&table->v_cols[i]) dict_v_col_t();
+	}
 
 	/* true means that the stats latch will be enabled -
 	dict_table_stats_lock() will not be noop. */
@@ -227,7 +230,7 @@ dict_mem_table_free(
 	/* Clean up virtual index info structures that are registered
 	with virtual columns */
 	for (ulint i = 0; i < table->n_v_def; i++) {
-		UT_DELETE(dict_table_get_nth_v_col(table, i)->v_indexes);
+		dict_table_get_nth_v_col(table, i)->~dict_v_col_t();
 	}
 
 	UT_DELETE(table->s_cols);
@@ -409,7 +412,7 @@ dict_mem_table_add_v_col(
 	v_col->num_base = num_base;
 
 	/* Initialize the index list for virtual columns */
-	v_col->v_indexes = UT_NEW_NOKEY(dict_v_idx_list());
+	ut_ad(v_col->v_indexes.empty());
 	v_col->n_v_indexes = 0;
 
 	return(v_col);
@@ -857,7 +860,7 @@ dict_mem_fill_vcol_has_index(
 			continue;
 		}
 
-		for (const auto& v_idx : *v_col->v_indexes) {
+		for (const auto& v_idx : v_col->v_indexes) {
 			if (v_idx.index != index) {
 				continue;
 			}

storage/innobase/handler/handler0alter.cc

@@ -590,7 +590,7 @@ inline bool dict_table_t::instant_column(const dict_table_t& table,
 
 	for (unsigned i = 0; i < n_v_def; i++) {
 		dict_v_col_t& v = v_cols[i];
-		v.v_indexes = UT_NEW_NOKEY(dict_v_idx_list());
+		DBUG_ASSERT(v.v_indexes.empty());
 		v.n_v_indexes = 0;
 		v.base_col = static_cast<dict_col_t**>(
 			mem_heap_dup(heap, v.base_col,
@@ -699,7 +699,7 @@ dup_dropped:
 			if (f.col->is_virtual()) {
 				dict_v_col_t* v_col = reinterpret_cast
 					<dict_v_col_t*>(f.col);
-				v_col->v_indexes->push_front(
+				v_col->v_indexes.push_front(
 					dict_v_idx_t(index, i));
 				v_col->n_v_indexes++;
 			}
@@ -776,7 +776,7 @@ inline void dict_table_t::rollback_instant(
 	}
 
 	for (unsigned i = n_v_cols; i--; ) {
-		UT_DELETE(v_cols[i].v_indexes);
+		v_cols[i].~dict_v_col_t();
 	}
 
 	index->n_core_fields = (index->n_fields == index->n_core_fields)
@@ -1030,7 +1030,7 @@ struct ha_innobase_inplace_ctx : public inplace_alter_handler_ctx
 				dict_mem_index_free(index);
 			}
 			for (unsigned i = old_n_v_cols; i--; ) {
-				UT_DELETE(old_v_cols[i].v_indexes);
+				old_v_cols[i].~dict_v_col_t();
 			}
 			if (instant_table->fts) {
 				fts_free(instant_table);
@@ -4950,6 +4950,7 @@ prepare_inplace_add_virtual(
 			}
 		}
 
+		new (&ctx->add_vcol[j]) dict_v_col_t();
 		ctx->add_vcol[j].m_col.prtype = dtype_form_prtype(
 						field_type, charset_no);
 
@@ -4966,8 +4967,6 @@ prepare_inplace_add_virtual(
 		ctx->add_vcol[j].v_pos = ctx->old_table->n_v_cols
 					 - ctx->num_to_drop_vcol + j;
 
-		/* No need to track the list */
-		ctx->add_vcol[j].v_indexes = NULL;
 		ctx->add_vcol[j].n_v_indexes = 0;
 		/* MDEV-17468: Do this on ctx->instant_table later */
 		innodb_base_col_setup(ctx->old_table, field, &ctx->add_vcol[j]);
@@ -11180,7 +11179,7 @@ foreign_fail:
 		dict_table_close(m_prebuilt->table, true, false);
 		if (ctx0->is_instant()) {
 			for (unsigned i = ctx0->old_n_v_cols; i--; ) {
-				UT_DELETE(ctx0->old_v_cols[i].v_indexes);
+				ctx0->old_v_cols[i].~dict_v_col_t();
 			}
 			const_cast<unsigned&>(ctx0->old_n_v_cols) = 0;
 		}

storage/innobase/include/dict0mem.h

@@ -705,10 +705,6 @@ struct dict_v_idx_t {
 		: index(index), nth_field(nth_field) {}
 };
 
-/** Index list to put in dict_v_col_t */
-typedef	std::forward_list<dict_v_idx_t, ut_allocator<dict_v_idx_t> >
-dict_v_idx_list;
-
 /** Data structure for a virtual column in a table */
 struct dict_v_col_t{
 	/** column structure */
@@ -726,31 +722,30 @@ struct dict_v_col_t{
 	/** number of indexes */
 	unsigned		n_v_indexes:12;
 
-	/** Virtual index list, and column position in the index,
-	the allocated memory is not from table->heap */
-	dict_v_idx_list*	v_indexes;
+	/** Virtual index list, and column position in the index */
+	std::forward_list<dict_v_idx_t, ut_allocator<dict_v_idx_t> >
+	v_indexes;
 
 	/** Detach the column from an index.
 	@param[in]	index	index to be detached from */
 	void detach(const dict_index_t& index)
 	{
-		ut_ad(!n_v_indexes || v_indexes);
 		if (!n_v_indexes) return;
-		auto i = v_indexes->before_begin();
+		auto i = v_indexes.before_begin();
 		ut_d(unsigned n = 0);
 		do {
 			auto prev = i++;
-			if (i == v_indexes->end()) {
+			if (i == v_indexes.end()) {
 				ut_ad(n == n_v_indexes);
 				return;
 			}
 			ut_ad(++n <= n_v_indexes);
 			if (i->index == &index) {
-				v_indexes->erase_after(prev);
+				v_indexes.erase_after(prev);
 				n_v_indexes--;
 				return;
 			}
-		} while (i != v_indexes->end());
+		} while (i != v_indexes.end());
 	}
 };
 

storage/innobase/trx/trx0rec.cc

@@ -259,7 +259,7 @@ trx_undo_log_v_idx(
 
 	ptr += mach_write_compressed(ptr, n_idx);
 
-	for (const auto& v_index : *vcol->v_indexes) {
+	for (const auto& v_index : vcol->v_indexes) {
 		ptr += mach_write_compressed(
 			ptr, static_cast<ulint>(v_index.index->id));
 
@@ -1021,7 +1021,7 @@ trx_undo_page_report_modify(
 				on them */
 				if (upd_fld_is_virtual_col(fld)
 				    && dict_table_get_nth_v_col(
-					    table, pos)->v_indexes->empty()) {
+					    table, pos)->v_indexes.empty()) {
 					n_updated--;
 				}
 			}
@@ -1062,7 +1062,7 @@ trx_undo_page_report_modify(
 				an online alter table */
 				if (dict_index_is_online_ddl(index)
 				    && dict_table_get_nth_v_col(
-					table, pos)->v_indexes->empty()) {
+					table, pos)->v_indexes.empty()) {
 					continue;
 				}