8.91. registry_set_timestamp(text, timestamp without time zone)

    DECLARE
    	p_key		alias for $1;
    	p_value		alias for $2;
    BEGIN
    	if p_value is null then
    		delete from sl_registry
    				where reg_key = p_key;
    	else
    		lock table sl_registry;
    		update sl_registry
    				set reg_timestamp = p_value
    				where reg_key = p_key;
    		if not found then
    			insert into sl_registry (reg_key, reg_timestamp)
    					values (p_key, p_value);
    		end if;
    	end if;
    	return p_value;
    END;