+ /* "isRoot" was not part of the original schema definition. Before it was
+ * added, there was no support for garbage collection. So, for backward
+ * compatibility, if the root set is empty then assume that every table is
+ * in the root set. */
+ if (root_set_size(schema) == 0) {
+ SHASH_FOR_EACH (node, &schema->tables) {
+ struct ovsdb_table_schema *table = node->data;
+
+ table->is_root = true;
+ }
+ }
+
+ /* Validate that all refTables refer to the names of tables that exist.
+ *
+ * Also force certain columns to be persistent, as explained in
+ * ovsdb_schema_check_ref_table(). This requires 'is_root' to be known, so
+ * this must follow the loop updating 'is_root' above. */