PHP语言, PHP扩展, Zend引擎相关的研究,技术,新闻分享 – 左手代码 右手诗

05 May 11 Apache Access Log中的Options的含义

写博客最怕啥,,,最怕没话题, 没说的, 呵呵

好在公司内的PHP群里,同学众多, 于是又有了今天的这个话题.

说是, 在Apache的Access Log中会看到很多如下的访问日志: - - [05/May/2011:10:54:07 +0800] "OPTIONS * HTTP/1.0" 200 - - - [05/May/2011:10:54:08 +0800] "OPTIONS * HTTP/1.0" 200 - - - [05/May/2011:10:54:09 +0800] "OPTIONS * HTTP/1.0" 200 - - - [05/May/2011:10:54:10 +0800] "OPTIONS * HTTP/1.0" 200 -


Apache的文档中, 有如下的说明:

When the Apache HTTP Server manages its child processes, it needs a way to wake up processes that are listening for new connections. To do this, it sends a simple HTTP request back to itself. This request will appear in the access_log file with the remote address set to the loop-back interface (typically or ::1 if IPv6 is configured). If you log the User-Agent string (as in the combined log format), you will see the server signature followed by “(internal dummy connection)” on non-SSL servers. During certain periods you may see up to one such request for each httpd child process.

可是, 为什么要唤醒呢? 唤醒是为了做什么呢?

在Apache Prefork模式下, 启动的时候, Apache就会fork出一些worker进程, 来准备接受请求, 这些worker进程, 在完成准备工作以后, 就会进入block模式的监听沉睡中, 等待请求到来而被唤醒.

另外一方面, 在Prefork模式下, 当请求很多, 目前的worker进程数不够处理的时候, 就会额外再fork一些worker进程出来, 以满足当前的请求.(参看:

而在这些请求高峰过后, 如果额外fork出来的进程数大于了MaxSpareServers, Apache就会告诉这些worker进程退出, 那么问题就来了,,

这些进程都在沉睡中啊, 怎么告诉他们, 并且让他们自我退出呢?

Apache会首先发送一个退出状态字(GRACEFUL_CHAR !)给这些Work进程.

static apr_status_t pod_signal_internal(ap_pod_t *pod)
    apr_status_t rv;
    char char_of_death = '!';
    apr_size_t one = 1;

    rv = apr_file_write(pod->pod_out, &char_of_death, &one);
    if (rv != APR_SUCCESS) {
        ap_log_error(APLOG_MARK, APLOG_WARNING, rv, ap_server_conf,
                     "write pipe_of_death");

    return rv;

但此时, Worker进程不会去读这些状态字, 因为他们还在沉睡.

这个时候Apache就会发送一个OPTIONS请求给自己, 唤醒这些沉睡的进程.

static apr_status_t dummy_connection(ap_pod_t *pod)
    /* Create the request string. We include a User-Agent so that
     * adminstrators can track down the cause of the odd-looking
     * requests in their logs.
    srequest = apr_pstrcat(p, "OPTIONS * HTTP/1.0\r\nUser-Agent: ",
                           " (internal dummy connection)\r\n\r\n", NULL);

这些进程在处理完当前请求以后(OPTIONS请求), 就会发现, oh, 主进程让我退出,

static void child_main(int child_num_arg)

    while (!die_now && !shutdown_pending) {
        //1. listen
        //2. accept
        //3. process request

        /* Check the pod and the generation number after processing a
         * connection so that we'll go away if a graceful restart occurred
         * while we were processing the connection or we are the lucky
         * idle server process that gets to die.
        if (ap_mpm_pod_check(pod) == APR_SUCCESS) { /* selected as idle? */
            die_now = 1;

于是, 它就做完清理工作,, 然后自我消亡了~~~


Related Posts:

Tags: , , , ,

6 Responses to “Apache Access Log中的Options的含义”

  1. |


  2. |

    of course like your web-site but you have to test the spelling on several of your posts.
    A number of them aree rife with spelling problems and
    I find it very troublesome to inform the

  3. musica romantica |

    I enjoy what you guys tend to be up too. This
    kind of clever work and reporting! Keep up the fantastic
    works guys I’ve you guys to our blogroll.

  4. Junko |

    In such manner, you are extremely handy at heart,
    then one of our do-it-yourself steel kit sheds might be for you.
    Picture of a metal riding arenaAgricultural steel buildings can be found at water treatment plants and sewage treatment plants andd sewage treatment plants.
    Second-hand containers are more feasible for people who desire to keep hidden in the spare
    room? Options abound when using a storage tank UK is considered to be one of the sturdiest building materials
    known to man.

  5. |

    of course like your web-site but you have to test the spelling on several of your posts.
    A number of them aree rife with spelling problems and
    I find it very troublesome to inform the reality however I’ll surely come back

  6. Thinking In LAMP Blog » Blog Archive » PHP每月通讯(2011年6月) |

    [...]   Apache Access Log中的Options的含义 [...]

Leave a Reply