慢連接&LazyParser
Author:放翁（文初）
Mail:fangweng@taobao.com
Tblog:weibo.com/fangweng
這里要從實(shí)際的測(cè)試中給Web應(yīng)用開(kāi)發(fā)者一個(gè)比較直觀的關(guān)于慢連接優(yōu)化的建議。
測(cè)試目標(biāo)：
1． 證明慢連接對(duì)于Java的應(yīng)用容器的影響。
2． 不同前端反向代理服務(wù)器對(duì)于慢連接的處理差異。
3． 如何利用LazyParser的方式來(lái)優(yōu)化慢連接請(qǐng)求（特別是大數(shù)據(jù)量的一些異常請(qǐng)求的處理）
測(cè)試部署環(huán)境描述：
Apache服務(wù)器（2.2.19版本）配置基本沒(méi)變，增加了http proxy模塊作為反向代理。
Nginx服務(wù)器（1.0.4版本）配置基本沒(méi)變，增加了反向代理。
Jetty服務(wù)器（7.1.6版本）配置基本沒(méi)變。Jetty的Lazy解析緩存為8k。
部署如下，外部請(qǐng)求可以通過(guò)三個(gè)入口訪問(wèn)應(yīng)用真實(shí)邏輯。（apache,nginx,jetty）
測(cè)試代碼：
服務(wù)端：
簡(jiǎn)單描述一下邏輯：
1. 根據(jù)http消息頭判斷采用lazy還是普通方式解析。
2. 輸出start test表示開(kāi)始。
3. 獲取key1,key2的內(nèi)容，并記錄消耗時(shí)間輸出phase 1 use:xxx作為獲取這兩個(gè)參數(shù)的消耗。
4. 獲取key4的內(nèi)容，并記錄消耗時(shí)間輸出phase 2 use:xxx作為獲取這個(gè)參數(shù)的消耗。
5. 獲取key3的內(nèi)容，并記錄整個(gè)請(qǐng)求消耗的時(shí)間，輸出end total use:xxx，作為整個(gè)處理消耗的時(shí)間。
客戶端代碼：
1． 配置不同入口訪問(wèn)應(yīng)用。
2． 是否設(shè)置使用lazy的http header來(lái)引導(dǎo)服務(wù)端處理。
3． 構(gòu)建參數(shù)集合，參數(shù)順序?yàn)椋?/span>key1,key2,key3,key4）。其中key3作為一個(gè)大數(shù)據(jù)字段可變，用于多個(gè)場(chǎng)景測(cè)試。
測(cè)試結(jié)果及分析：
1． 設(shè)置key3大小為1000個(gè)char，對(duì)比多個(gè)場(chǎng)景：
a. 不用lazy解析模式
(1) 通過(guò)nginx訪問(wèn)：
Nginx日志（第一位是消耗時(shí)間單位秒）：0.002 115.193.162.12 - - [20/Jun/2011:10:50:44 -0400] "POST /cometpipe/slowtest?key1=1 HTTP/1.1" 200 19 "-" "Jakarta Commons-HttpClient/3.0.1" "-"
Jetty日志：
start test: not use lazy
phase 1 use :0
phase 2 use :1
end total use:1
(2) 通過(guò) apache訪問(wèn)：
Apache日志：（第二位消耗時(shí)間單位微秒）：0 3513 115.193.162.12 - - [20/Jun/2011:10:53:24 -0400] "POST /cometpipe/slowtest?key1=1 HTTP/1.1" 200 9
Jetty日志：
start test: not use lazy
phase 1 use :0
phase 2 use :0
end total use:0
(3) 直接訪問(wèn)jetty：
Jetty日志：
start test: not use lazy
phase 1 use :1
phase 2 use :0
end total use:1
b. 用lazy解析模式
同樣是上面三種模式，web容器的日志就不寫(xiě)出來(lái)了結(jié)果一樣，下面主要是貼一下應(yīng)用服務(wù)器的情況:
----------------------------------------------------jetty
start test : uselazy
Jun 20, 2011 10:57:24 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1019
phase 1 use :1
Jun 20, 2011 10:57:24 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: -1
phase 2 use :0
end total use:1
-----------------------------------------------------------nginx
start test : uselazy
Jun 20, 2011 10:58:37 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1019
phase 1 use :0
Jun 20, 2011 10:58:37 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: -1
phase 2 use :0
end total use:0
-----------------------------------------------------------apache
start test : uselazy
Jun 20, 2011 10:58:45 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1019
phase 1 use :0
Jun 20, 2011 10:58:45 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: -1
phase 2 use :1
end total use:1
上面的輸出增加了一些，其實(shí)lazyparser在逐塊解析字節(jié)流的時(shí)候每次裝載數(shù)據(jù)的輸出，lazyparser的緩沖區(qū)當(dāng)前設(shè)置最大為8k，根據(jù)上面的情況可以看到不論哪一種方式，數(shù)據(jù)一次性都被裝載，不存在后端處理的差異。
2． 設(shè)置key3大小為100000個(gè)char，對(duì)比多個(gè)場(chǎng)景：
a. 不用lazy解析模式
(1) 通過(guò)nginx訪問(wèn)：
Nginx日志（第一位是消耗時(shí)間單位秒）：1.528 115.193.162.12 - - [20/Jun/2011:11:05:34 -0400] "POST /cometpipe/slowtest?key1=1 HTTP/1.1" 200 19 "-" "Jakarta Commons-HttpClient/3.0.1" "-"（消耗時(shí)間大幅上升）
Jetty日志：
start test: not use lazy
phase 1 use :5
phase 2 use :0
end total use:6
(2) 通過(guò) apache訪問(wèn)：
Apache日志：（第二位消耗時(shí)間單位微秒）：1 1502243 115.193.162.12 - - [20/Jun/2011:11:07:10 -0400] "POST /cometpipe/slowtest?key1=1 HTTP/1.1" 200 9
Jetty日志：
start test: not use lazy
phase 1 use :609
phase 2 use :0
end total use:609
(3) 直接訪問(wèn)jetty：
Jetty日志：
start test: not use lazy
phase 1 use :1463
phase 2 use :0
end total use:1463
從上面幾個(gè)數(shù)據(jù)來(lái)看，首先不論哪個(gè)入口進(jìn)去，總的時(shí)間處理都在1.5秒左右（我的網(wǎng)絡(luò)狀況還是比較爛），但nginx的數(shù)據(jù)堆積效果對(duì)jetty起到了明顯的保護(hù)作用，使得jetty整個(gè)容器線程池生命周期較短，可以處理更多的請(qǐng)求，apache數(shù)據(jù)堆積不是全量堆積，因此對(duì)于jetty來(lái)說(shuō)還需要自身的一些堆積處理（這點(diǎn)在后面的lazy模式下將會(huì)更加直觀的看到過(guò)程）
b. 用lazy解析模式
(1) 通過(guò)nginx訪問(wèn)：
Nginx日志（第一位是消耗時(shí)間單位秒）：1.513 115.193.162.12 - - [20/Jun/2011:11:13:22 -0400] "POST /cometpipe/slowtest?key1=1 HTTP/1.1" 200 19 "-" "Jakarta Commons-HttpClient/3.0.1" "-"（消耗時(shí)間大幅上升）
Jetty日志：
start test : uselazy
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 5911
phase 1 use :1
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 8192
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 3996
Jun 20, 2011 11:13:22 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: -1
phase 2 use :7
end total use:8
從上面的結(jié)果可以看到，nginx的數(shù)據(jù)堆積效果很好，jetty都是塞滿lazyparser的緩存大小來(lái)處理的，所以Java IO次數(shù)少，整體消耗時(shí)間短。
(2) 通過(guò) apache訪問(wèn)：
Apache日志：（第二位消耗時(shí)間單位微秒）：1 1521576 115.193.162.12 - - [20/Jun/2011:11:16:37 -0400] "POST /cometpipe/slowtest?key1=1 HTTP/1.1" 200 9
Jetty日志：
start test : uselazy
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 5787
phase 1 use :1
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 8192
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 2405
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:13,count: 8096
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:280,count: 8192
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 448
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:6,count: 8192
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 448
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:13,count: 8192
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 448
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:10,count: 8192
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 448
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:265,count: 8192
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 448
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:7,count: 8192
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 448
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:13,count: 8192
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 448
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:7,count: 8192
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 448
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:6,count: 6419
Jun 20, 2011 11:16:38 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: -1
phase 2 use :627
end total use:628
可以看到第一階段處理由于是lazy的模式，沒(méi)有像普通請(qǐng)求處理那樣消耗都在第一階段，而是把消耗時(shí)間落在了真正要拿那些數(shù)據(jù)處理的第二階段，同時(shí)可以看到apache有滿cache和非滿cache的數(shù)據(jù)后傳，同時(shí)由于是變積累邊傳遞，每次后傳所消耗的時(shí)間都要遠(yuǎn)大于nginx，因此對(duì)于jetty的保護(hù)較弱。（所以如果你不是用mod_jk去直接反向代理到后段的應(yīng)用容器（jboss,tomcat,jetty）都會(huì)使得應(yīng)用服務(wù)器load比較高，線程生命周期長(zhǎng)了，線程切換頻繁）
(3) 直接訪問(wèn)jetty：
Jetty日志：
start test : uselazy
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1217
phase 1 use :1
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:294,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:309,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:2,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:2,count: 1440
Jun 20, 2011 11:22:46 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:287,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:2,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:4,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:2,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:3,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:2,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:2,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:273,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:16,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:2,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:2,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:246,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:23,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:1,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 1440
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: 882
Jun 20, 2011 11:22:47 AM com.taobao.top.xbox.framework.http.LazyParser readBytes
SEVERE: timconsume:0,count: -1
phase 2 use :1532
end total use:1533
上面的輸出大家會(huì)看到雖然我給了8k的lazy解析緩沖區(qū)，但是每次過(guò)來(lái)的數(shù)據(jù)都是1440，這個(gè)數(shù)字的含義大家可以去查一下TCP傳輸?shù)臄?shù)據(jù)包大小定義。可以看到，其實(shí)如果網(wǎng)絡(luò)速度不佳，我們就會(huì)一個(gè)一個(gè)的得到數(shù)據(jù)包，Java IO次數(shù)及每次消耗的時(shí)間都會(huì)較長(zhǎng)，同時(shí)這也是直接把Java應(yīng)用服務(wù)器對(duì)外接收請(qǐng)求在高并發(fā)，慢請(qǐng)求的狀況下，系統(tǒng)壓力會(huì)遠(yuǎn)高于前端假設(shè)反向代理http服務(wù)器。
總結(jié)：
測(cè)試很簡(jiǎn)單，但說(shuō)明了幾個(gè)問(wèn)題：
1. 互聯(lián)網(wǎng)上的請(qǐng)求和內(nèi)網(wǎng)測(cè)試環(huán)境完全是兩碼事情（如果你還打算支持mobile）。
2. Nginx和apache作為反向代理，對(duì)于后端的web容器的處理是有一定幫助的，特別是nginx，作為數(shù)據(jù)堆積和海量連接的并發(fā)支持能夠很好的充分利用后端應(yīng)用服務(wù)器的線程資源。
3. 不論哪一種模式，總體請(qǐng)求時(shí)間都是差不多的，因此RT在后端資源不是瓶頸的時(shí)候，不會(huì)由于你架設(shè)了反向代理而得到優(yōu)化，反而會(huì)有所增長(zhǎng)（畢竟多了一層中轉(zhuǎn)）
4. Lazy處理可以極大提高串行化分階段處理的性能（特別是在沒(méi)有數(shù)據(jù)堆積的情況下或者是apache這樣的半數(shù)據(jù)堆積的情況下，在nginx模式下失效）。比如一個(gè)很大的請(qǐng)求，如果在第一階段就被判斷系統(tǒng)參數(shù)校驗(yàn)錯(cuò)誤，那么后續(xù)的請(qǐng)求數(shù)據(jù)將直接拒絕（或者類似于有圖片大小限制或者是圖片個(gè)數(shù)限制的判斷）。
5. 應(yīng)用服務(wù)器（jetty,tomcat,jboss等等）不論使用nio或者bio模式，在慢連接的情況下都會(huì)有不小的性能消耗。
對(duì)于開(kāi)放平臺(tái)來(lái)說(shuō)，每天處理幾十億的api call，和普通的web應(yīng)用不同，每一次請(qǐng)求的時(shí)間就貫穿于容器對(duì)于數(shù)據(jù)流的載入，處理，一點(diǎn)優(yōu)化都可以極大地提高整體的處理能力和資源使用效率，當(dāng)前開(kāi)放平臺(tái)采用nginx+jetty，雖然可以保護(hù)到jetty對(duì)于高并發(fā)的慢連接支持，但是整體的響應(yīng)時(shí)間及資源消耗狀況都沒(méi)有被充分利用到（雖然Lazy解析已經(jīng)被裝配上，apache+jboss時(shí)代比較有效果），因此后續(xù)考慮要做三種改進(jìn)：1.讓nginx支持部分?jǐn)?shù)據(jù)堆積模式。2.優(yōu)化jetty的bio模式的nio。3.替換掉jetty的nio模塊（netty）。最終不是讓前端采用部分堆積，就是直接暴露應(yīng)用容器到外部，再加上lazyparser，來(lái)完成對(duì)于慢連接的優(yōu)化。