only push limit down if 1 thread and can use main

Author: noahisaksen

src/storage/postgres_optimizer.cpp

@@ -54,6 +54,11 @@ static void OptimizePostgresScanLimitPushdown(unique_ptr<LogicalOperator> &op) {
 		}
 
 		auto &bind_data = get.bind_data->Cast<PostgresBindData>();
+		if (bind_data.max_threads != 1 || !bind_data.can_use_main_thread) {
+			// cannot push down limit/offset if we are not using the main thread
+			OptimizePostgresScanLimitPushdown(op->children[0]);
+			return;
+		}
 
 		string generated_limit_clause = "";
 		if (limit.limit_val.Type() != LimitNodeType::UNSET) {