nginx proxy_buffer_size 解决后端服务传输数据过多，其实是header过大的问题

这三个参数已设置就搞定了额

proxy_buffer_size 64k;
proxy_buffers   4 32k;
proxy_busy_buffers_size 64k;

本着精益求精的精神我翻了官网
官网解释

总体来说我还是没懂。我把报错信息放出来，以后用得着。
开发说nginx502了，后端访问jesery没问题

不行
curl -i -v "test.lebi.letv.cn/report/rest/saiku/api/query/7C53220D-A870-1FE3-9353-4A6F967F25CB/result/metadata/hierarchies/%5BDM_REC.DIM_LIVE_STATION%5D.%5BDM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME%5D/levels/DM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME?result=false&_=1489736122190"
可以
curl -i -v "http://10.142.165.45:8080/report/rest/saiku/api/query/7C53220D-A870-1FE3-9353-4A6F967F25CB/result/metadata/hierarchies/%5BDM_REC.DIM_LIVE_STATION%5D.%5BDM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME%5D/levels/DM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME?result=false&_=1489736122190"

日志对比

返回502
"10.73.137.12","[17/Mar/2017:16:32:08 +0800]","HTTP/1.1","-","GET","/report/rest/saiku/api/query/7C53220D-A870-1FE3-9353-4A6F967F25CB/result/metadata/hierarchies/%5BDM_REC.DIM_LIVE_STATION%5D.%5BDM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME%5D/levels/DM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME?result=false&_=1489736122190","502","http://test.lebi.letv.cn/report/rest/saiku/api/query/7C53220D-A870-1FE3-9353-4A6F967F25CB/result/metadata/hierarchies/%5BDM_REC.DIM_LIVE_STATION%5D.%5BDM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME%5D/levels/DM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME?result=false&_=1489736122190","172","0.157","10.142.165.45:8080","-","curl/7.35.0","0.157","329","328"

正常了
"10.73.137.12","[17/Mar/2017:16:32:47 +0800]","HTTP/1.1","-","GET","/report/rest/saiku/api/query/7C53220D-A870-1FE3-9353-4A6F967F25CB/result/metadata/hierarchies/%5BDM_REC.DIM_LIVE_STATION%5D.%5BDM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME%5D/levels/DM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME?result=false&_=1489736122190","200","http://test.lebi.letv.cn/report/rest/saiku/api/query/7C53220D-A870-1FE3-9353-4A6F967F25CB/result/metadata/hierarchies/%5BDM_REC.DIM_LIVE_STATION%5D.%5BDM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME%5D/levels/DM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME?result=false&_=1489736122190","1342118","4.350","10.142.165.45:8080","-","curl/7.35.0","0.180","329","1346306"

我测了下，返回的json数据大约1.3M，可能是返回值太大，超过了阈值，但是超过了哪个呢，比较纠结。

查看error日志得到upstream sent too big header while reading response header from upstream，说header太大了。好好学习下header

这里写图片描述

2017/03/17 16:32:08 [error] 17441#0: *403548696 upstream sent too big header while reading response header from upstream, client: 10.73.137.12, server: test.lebi.letv.cn, request: "GET /report/rest/saiku/api/query/7C53220D-A870-1FE3-9353-4A6F967F25CB/result/metadata/hierarchies/%5BDM_REC.DIM_LIVE_STATION%5D.%5BDM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME%5D/levels/DM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME?result=false&_=1489736122190 HTTP/1.1", upstream: "http://10.142.165.45:8080/report/rest/saiku/api/query/7C53220D-A870-1FE3-9353-4A6F967F25CB/result/metadata/hierarchies/%5BDM_REC.DIM_LIVE_STATION%5D.%5BDM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME%5D/levels/DM_REC.DIM_LIVE_STATION.LIVE_STATION_NAME?result=false&_=1489736122190", host: "test.lebi.letv.cn"