my server use nginx+php-fpm ,nginx as reverse proxy server,, but our nginx access log got a lot of 499 response code,,,,the document say that 499 means "client abort the connection ",,,,,i think the the reason cause " client abort connection" comes from two: the first is client is in weak network environment, client request can't be delivered successfully, and client has canceled the request. the second is php-fpm is too busy,,,such as for a long time nginx can't get the response from upstream server(php-fpm) ,,,and the client canceled the request.


my question is the first reason can be accepted . but the second can't. since i checked the nginx access log,, when there is 499 response code in nginx access log file ,,,there is always no "upstream_response_time" field value in it, seems the php-fpm is not busy and can server it successfully . here is some sample 499 nginx access log and some explanation:



171.213.141.240 - 31/Oct/2012:13:09:34 +0800 POST /php/xyz/iface/?key=be7fc0cdf0afbfedff1e09ec6443823a&device_id=351870052329449&network=1&ua=LT18i&os=2.3.4&version=3.7&category_id=2&f_ps=10&s=5&ps=30&pn=1&pcat=2&up_tm=1351655451272 HTTP/1.1 499 0($body_bytes_sent) - Dalvik/1.4.0 (Linux; U; Android 2.3.4; LT18i Build/4.0.2.A.0.62) 21($content_length) 2.448($request_time) -($upstream_response_time) - - -
124.236.132.41 - 31/Oct/2012:13:09:34 +0800 POST /php/xyz/iface/?key=3179f25bc69e815ad828327ccf10c539&device_id=356330048225461&network=1&ua=GT-S5670&os=2.2.1&version=3.7.1&category_id=0&f_ps=10&s=5&ps=30&pn=1&pcat=2&f=1 HTTP/1.1 499 0 - Dalvik/1.2.0 (Linux; U; Android 2.2.1; GT-S5670 Build/FROYO) 44 10.034 -