Ajax请求偶尔会在Chrome中停滞很长时间。
如果有人能帮助我的话,我终于设法复制了它并保存了发布在这里所需的所有相关数据。
Chrome开发工具的时间线显示42.62秒的停止请求,如以下屏幕截图所示:
并且在chrome://net-internals/#events
(对于事件日志,请到最后)页面我发现最多的时间是由两个事件花费:
都获得ERR_CONNECTION_RESET
。
我认为错误是请求停滞了这么久的原因。
任何人都可以解释错误吗?
以下是请求的事件日志,我还将完整事件导出为json,您可以从here获取,然后在Chrome chrome://net-internals/#events
页面内恢复。请注意请求网址是内部的,因此可能无法从公共网络访问:
193486: URL_REQUEST
http://qa.tieba.baidu.com/release/getReleaseHistory?projectId=fum1.0.593
Start Time: 2015-01-02 17:51:05.323
t= 1 [st= 0] +REQUEST_ALIVE [dt=42741]
t= 1 [st= 0] URL_REQUEST_DELEGATE [dt=0]
t= 1 [st= 0] +URL_REQUEST_START_JOB [dt=42740]
--> load_flags = 339804160 (BYPASS_DATA_REDUCTION_PROXY | MAYBE_USER_GESTURE | REPORT_RAW_HEADERS | VERIFY_EV_CERT)
--> method = "GET"
--> priority = "LOW"
--> url = "http://qa.tieba.baidu.com/release/getReleaseHistory?projectId=fum1.0.593"
t= 2 [st= 1] URL_REQUEST_DELEGATE [dt=0]
t= 2 [st= 1] HTTP_CACHE_GET_BACKEND [dt=0]
t= 2 [st= 1] HTTP_CACHE_OPEN_ENTRY [dt=0]
t= 2 [st= 1] HTTP_CACHE_ADD_TO_ENTRY [dt=0]
t= 2 [st= 1] HTTP_CACHE_READ_INFO [dt=0]
t= 2 [st= 1] URL_REQUEST_DELEGATE [dt=0]
t= 2 [st= 1] +HTTP_STREAM_REQUEST [dt=2]
t= 4 [st= 3] HTTP_STREAM_REQUEST_BOUND_TO_JOB
--> source_dependency = 193488 (HTTP_STREAM_JOB)
t= 4 [st= 3] -HTTP_STREAM_REQUEST
t= 4 [st= 3] +HTTP_TRANSACTION_SEND_REQUEST [dt=0]
t= 4 [st= 3] HTTP_TRANSACTION_SEND_REQUEST_HEADERS
--> GET /release/getReleaseHistory?projectId=fum1.0.593 HTTP/1.1
Host: qa.tieba.baidu.com
Connection: keep-alive
Accept: application/json, text/plain, */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36
Referer: http://qa.tieba.baidu.com/project/
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Cookie: [268 bytes were stripped]
t= 4 [st= 3] -HTTP_TRANSACTION_SEND_REQUEST
t= 4 [st= 3] +HTTP_TRANSACTION_READ_HEADERS [dt=21301]
t= 4 [st= 3] HTTP_STREAM_PARSER_READ_HEADERS [dt=21301]
--> net_error = -101 (ERR_CONNECTION_RESET)
t=21305 [st=21304] HTTP_TRANSACTION_RESTART_AFTER_ERROR
--> net_error = -101 (ERR_CONNECTION_RESET)
t=21305 [st=21304] -HTTP_TRANSACTION_READ_HEADERS
t=21305 [st=21304] +HTTP_STREAM_REQUEST [dt=3]
t=21307 [st=21306] HTTP_STREAM_REQUEST_BOUND_TO_JOB
--> source_dependency = 193494 (HTTP_STREAM_JOB)
t=21308 [st=21307] -HTTP_STREAM_REQUEST
t=21308 [st=21307] +HTTP_TRANSACTION_SEND_REQUEST [dt=3]
t=21308 [st=21307] HTTP_TRANSACTION_SEND_REQUEST_HEADERS
--> GET /release/getReleaseHistory?projectId=fum1.0.593 HTTP/1.1
Host: qa.tieba.baidu.com
Connection: keep-alive
Accept: application/json, text/plain, */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36
Referer: http://qa.tieba.baidu.com/project/
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Cookie: [268 bytes were stripped]
t=21311 [st=21310] -HTTP_TRANSACTION_SEND_REQUEST
t=21311 [st=21310] +HTTP_TRANSACTION_READ_HEADERS [dt=21304]
t=21311 [st=21310] HTTP_STREAM_PARSER_READ_HEADERS [dt=21304]
--> net_error = -101 (ERR_CONNECTION_RESET)
t=42615 [st=42614] HTTP_TRANSACTION_RESTART_AFTER_ERROR
--> net_error = -101 (ERR_CONNECTION_RESET)
t=42615 [st=42614] -HTTP_TRANSACTION_READ_HEADERS
t=42615 [st=42614] +HTTP_STREAM_REQUEST [dt=12]
t=42627 [st=42626] HTTP_STREAM_REQUEST_BOUND_TO_JOB
--> source_dependency = 193498 (HTTP_STREAM_JOB)
t=42627 [st=42626] -HTTP_STREAM_REQUEST
t=42627 [st=42626] +HTTP_TRANSACTION_SEND_REQUEST [dt=2]
t=42627 [st=42626] HTTP_TRANSACTION_SEND_REQUEST_HEADERS
--> GET /release/getReleaseHistory?projectId=fum1.0.593 HTTP/1.1
Host: qa.tieba.baidu.com
Connection: keep-alive
Accept: application/json, text/plain, */*
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36
Referer: http://qa.tieba.baidu.com/project/
Accept-Encoding: gzip, deflate, sdch
Accept-Language: en-US,en;q=0.8
Cookie: [268 bytes were stripped]
t=42629 [st=42628] -HTTP_TRANSACTION_SEND_REQUEST
t=42629 [st=42628] +HTTP_TRANSACTION_READ_HEADERS [dt=112]
t=42629 [st=42628] HTTP_STREAM_PARSER_READ_HEADERS [dt=112]
t=42741 [st=42740] HTTP_TRANSACTION_READ_RESPONSE_HEADERS
--> HTTP/1.1 200 OK
Date: Fri, 02 Jan 2015 09:51:48 GMT
Content-Type: application/json; charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Cache-Control: no-cache
tracecode: 31079600320335034634010217
tracecode: 31079600320537995786010217
Server: Apache
t=42741 [st=42740] -HTTP_TRANSACTION_READ_HEADERS
t=42741 [st=42740] HTTP_CACHE_WRITE_INFO [dt=0]
t=42741 [st=42740] HTTP_CACHE_WRITE_DATA [dt=0]
t=42741 [st=42740] HTTP_CACHE_WRITE_INFO [dt=0]
t=42741 [st=42740] URL_REQUEST_DELEGATE [dt=0]
t=42741 [st=42740] -URL_REQUEST_START_JOB
t=42741 [st=42740] URL_REQUEST_DELEGATE [dt=0]
t=42741 [st=42740] HTTP_TRANSACTION_READ_BODY [dt=0]
t=42741 [st=42740] HTTP_CACHE_WRITE_DATA [dt=0]
t=42741 [st=42740] HTTP_TRANSACTION_READ_BODY [dt=0]
t=42741 [st=42740] HTTP_CACHE_WRITE_DATA [dt=0]
t=42742 [st=42741] -REQUEST_ALIVE
答案 0 :(得分:14)
我曾经遇到过类似的问题。问题的原因是每个浏览器都限制了到服务器的最大TCP连接数。对于chrome,限制为6。当您使用代理服务器时,问题更加突出,因为所有请求都是同一台服务器(代理服务器)。
Chrome不允许您更改此限制。事实上不应该这样。如果您想了解更多关于此限制存在的原因以及其他浏览器的限制,请阅读this article。
此限制很少出现问题的原因是因为对同一主机的多个HTTP请求主要是连续发送,而不是并行发送,最好是通过相同的TCP连接发送。
如果您经常遇到此问题,原因可能是:
服务器不支持持久性TCP连接:如果仅在访问特定服务器时出现问题,原因可能是chrome正在获取多个资源(如图像,CSS)并行连接上的文件等)。因为在您的情况下,服务器位于本地网络上,您可能需要请求服务器的管理员添加对持久TCP连接的支持。
多个持久连接已打开:如果您在代理服务器后面工作,则同时下载多个文件或打开保持TCP连接打开的网站可能是导致问题的原因。要摆脱它,你所能做的就是不要同时下载很多东西(或者在不同的浏览器中下载,如果你不得不这样做)。
PS:错误 net_error = -101(ERR_CONNECTION_RESET)不是由于标头无效,而是因为超时,等待之前与服务器的某些连接关闭。
答案 1 :(得分:9)
这里有类似的问题,似乎经过一段时间后,操作系统关闭(我假设)套接字铬试用了大约3分钟。
这也被列为铬论坛中的一个错误。我猜测缺少某种"保持活力"机制。: https://code.google.com/p/chromium/issues/detail?id=447463
我的错误消息略有不同,但可能是由于我的应用程序通过SSL进行调用。这是我在chrome:// net-internals中看到的内容:
第一个chrome找到一个现有套接字并且请求与它相关联(HTTP_STREAM_JOB):
t=1572 [st=0] HTTP2_SESSION_POOL_FOUND_EXISTING_SESSION
--> source_dependency = 1347215 (HTTP2_SESSION)
t=1572 [st=0] HTTP_STREAM_JOB_BOUND_TO_REQUEST
--> source_dependency = 1348612 (URL_REQUEST)
t=1572 [st=0] -HTTP_STREAM_JOB
然后回到(URL_REQUEST)你会看到它超时,注意从t = 1572到t = 11573的时间间隔10秒:
t= 1572 [st= 0] HTTP2_SESSION_SEND_DATA
--> fin = true
--> size = 48
--> stream_id = 3
t= 1572 [st= 0] HTTP2_SESSION_UPDATE_SEND_WINDOW
--> delta = -48
--> window_size = 2147483551
t=11573 [st=10001] HTTP2_SESSION_CLOSE
--> description = "Failed ping."
--> net_error = -352 (ERR_SPDY_PING_FAILED)
显然,当chrome尝试调整现有套接字上的窗口大小时会出现超时。我认为这是由于套接字不活动。
我打算尝试以60秒的间隔执行某种心跳请求,看看问题是否仍然存在。我将发布带有结果的更新。
更新:
将以下代码添加到每个页面上加载的javascript中。这是从公共根目录中检索一个空的html文档:
$(document).ready(function() {
$.keepalive =
setInterval(function() {
$.ajax({
url: '/ping.html',
cache: false
});
}, 60000);
});
这似乎有助于保持插座打开,即使下面的示例显示在#34;真实"之间约6分钟。调用:
每次呼叫570B,间隔60秒,ping呼叫每24小时(每个浏览器会话)将增加大约800kb的带宽使用量。我不确定服务器上会产生多少CPU开销。
为了比较,BEFORE:
必须有一个更好的解决方案,但我还没能找到一个。