public function add_bucket($bucket)
	{
		// create the bucket by copying values from the default bucket
		$this->max_children[$bucket] = $this->max_children[self::DEFAULT_BUCKET];
		$this->child_single_work_item[$bucket] = $this->child_single_work_item[self::DEFAULT_BUCKET];
		$this->max_work_per_child[$bucket] = $this->max_work_per_child[self::DEFAULT_BUCKET];
		$this->child_max_run_time[$bucket] = $this->child_max_run_time[self::DEFAULT_BUCKET];
		$this->child_single_work_item[$bucket] = $this->child_single_work_item[self::DEFAULT_BUCKET];
		$this->child_function_run[$bucket] = $this->child_function_run[self::DEFAULT_BUCKET];
		$this->parent_function_fork[$bucket] = $this->parent_function_fork[self::DEFAULT_BUCKET];
		$this->child_function_sighup[$bucket] = $this->child_function_sighup[self::DEFAULT_BUCKET];
		$this->child_function_exit[$bucket] = $this->child_function_exit[self::DEFAULT_BUCKET];
		$this->child_function_timeout[$bucket] = $this->child_function_timeout[self::DEFAULT_BUCKET];
		$this->parent_function_child_exited[$bucket] = $this->parent_function_child_exited[self::DEFAULT_BUCKET];
		$this->child_persistent_mode[$bucket] = $this->child_persistent_mode[self::DEFAULT_BUCKET];
		$this->child_persistent_mode_data[$bucket] = $this->child_persistent_mode_data[self::DEFAULT_BUCKET];
		$this->work_units[$bucket] = array();
		$this->buckets[$bucket] = $bucket;
		$this->results[$bucket] = array();
	}