性能优化（一 测试环境准备）

一。 使用vmware 创建CentOS 环境
安装 redis 使用tomcat 连接宿主机器上的mysql 使用jmater 进行压力测试

        centos 配置  由于是vm 内存3G  处理2 cpu  宿主机 i5-9400F 
        jmeter 测试 
                    1.创建线程 
                    2. 使用阶段 使用一个api 进行请求
                    3. 起始使用 1500 进行查看
        
              500 个请求 ![](https://img2020.cnblogs.com/blog/883541/202009/883541-20200922135330864-1310374452.png)
              存在一些异常信息
              取样结果
              Thread Name:192.168.31.195测试 1-204
              Sample Start:2020-09-22 13:50:03 CST
              Load time:119
              Connect Time:119
              Latency:0
              Size in bytes:2374
              Sent bytes:0
              Headers size in bytes:0
              Body size in bytes:2374
              Sample Count:1
              Error Count:1
              Data type ("text"|"bin"|""):text
              Response code:Non HTTP response code: java.net.SocketException
              Response message:Non HTTP response message: Broken pipe (Write failed)


              HTTPSampleResult fields:
              ContentType: 
              DataEncoding: null

  响应数据
        java.net.SocketException: Broken pipe (Write failed)
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:111)
at java.net.SocketOutputStream.write(SocketOutputStream.java:155)
at org.apache.http.impl.io.SessionOutputBufferImpl.streamWrite(SessionOutputBufferImpl.java:124)
at org.apache.http.impl.io.SessionOutputBufferImpl.flushBuffer(SessionOutputBufferImpl.java:136)
at org.apache.http.impl.io.SessionOutputBufferImpl.flush(SessionOutputBufferImpl.java:144)
at org.apache.http.impl.BHttpConnectionBase.doFlush(BHttpConnectionBase.java:174)
at org.apache.http.impl.DefaultBHttpClientConnection.flush(DefaultBHttpClientConnection.java:183)
at org.apache.http.impl.conn.CPoolProxy.flush(CPoolProxy.java:167)
at org.apache.http.protocol.HttpRequestExecutor.doSendRequest(HttpRequestExecutor.java:241)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl$2.doSendRequest(HTTPHC4Impl.java:454)
at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:123)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:272)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:186)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.executeRequest(HTTPHC4Impl.java:930)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.sample(HTTPHC4Impl.java:641)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerProxy.sample(HTTPSamplerProxy.java:66)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1281)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1270)
at org.apache.jmeter.threads.JMeterThread.doSampling(JMeterThread.java:630)
at org.apache.jmeter.threads.JMeterThread.executeSamplePackage(JMeterThread.java:558)
at org.apache.jmeter.threads.JMeterThread.processSampler(JMeterThread.java:489)
at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:256)
at java.lang.Thread.run(Thread.java:748)

1000个 请求报错
org.apache.http.conn.HttpHostConnectException: Connect to 127.0.0.1:8888 [/127.0.0.1] failed: Operation timed out (Connection timed out)
at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:156)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl$JMeterDefaultHttpClientConnectionOperator.connect(HTTPHC4Impl.java:401)
at org.apache.http.impl.conn.PoolingHttpClientConnectionManager.connect(PoolingHttpClientConnectionManager.java:376)
at org.apache.http.impl.execchain.MainClientExec.establishRoute(MainClientExec.java:401)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:236)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:186)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.executeRequest(HTTPHC4Impl.java:930)
at org.apache.jmeter.protocol.http.sampler.HTTPHC4Impl.sample(HTTPHC4Impl.java:641)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerProxy.sample(HTTPSamplerProxy.java:66)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1281)
at org.apache.jmeter.protocol.http.sampler.HTTPSamplerBase.sample(HTTPSamplerBase.java:1270)
at org.apache.jmeter.threads.JMeterThread.doSampling(JMeterThread.java:630)
at org.apache.jmeter.threads.JMeterThread.executeSamplePackage(JMeterThread.java:558)
at org.apache.jmeter.threads.JMeterThread.processSampler(JMeterThread.java:489)
at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:256)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.net.ConnectException: Operation timed out (Connection timed out)
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:476)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:218)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:394)
at java.net.Socket.connect(Socket.java:606)
at org.apache.http.conn.socket.PlainConnectionSocketFactory.connectSocket(PlainConnectionSocketFactory.java:75)
at org.apache.http.impl.conn.DefaultHttpClientConnectionOperator.connect(DefaultHttpClientConnectionOperator.java:142)
... 19 more

以上使用的配置为 默认配置
              ====================================开始优化===============================

              1. 设置tomcat catalina.sh  添加 JAVA_OPTS=$JAVA_OPTS -server -Xms1024m -Xmx1024m
                对 1000 请求异常 未见效果
              
              2.配置nginx 
         events {
                  use epoll;
                  worker_connections  655350;
                  # worker_rlimit_nofile 65535;
                  multi_accept on;
        }      
                    配置后请求 仍旧无效 
              3. 查看 centos 系统可以打开的最大文件数  ulimit -n
                          执行命令
                    [root@www ~]# vi /etc/security/limits.conf 

End of file

•       soft  core   unlimit 
  

•       hard  core   unlimit 
  

•       soft  fsize  unlimited 
  

•       hard  fsize  unlimited 
  

•       soft  data   unlimited 
  

•       hard  data   unlimited 
  

•       soft  nproc  65535 
  

•       hard  nproc  63535 
  

•       soft  stack  unlimited 
  

•       hard  stack  unlimited 
  

•       soft  nofile  409600 
  

•       hard  nofile  409600
  
                    以上的调整后 还是 对  1000个请求 没有影响
                    4. 设置tomcat 的配置信息
                           1> 开启后台管理  
                                            在/conf/tomcat-users.xml文件中的<tomcat-users>标签里面添加如下内容
                                <!-- 修改配置文件，配置tomcat的管理用户 -->
                                <role rolename="manager"/>
                                <role rolename="manager-gui"/>
                                <role rolename="admin"/>
                                <role rolename="admin-gui"/>
                                <user username="tomcat" password="tomcat" roles="admin-gui,admin,manager-gui,manager"/>
                    如果是tomcat7，配置了tomcat用户就可以登录系统了，但是tomcat8中不行，还需要修改另一个配置文件，否则访问不了，提示403，打开webapps/manager/META-INF/context.xml文件
                          <!-- 将Valve标签的内容注释掉，保存退出即可 -->
  

                    将以上的方式 保存退出后 重启 tomcat   访问8080 端口  点击 Server Status 输入上边配置的用户名 和 密码 就能查看当前 tomcat 的状态信息了
        ![](https://img2020.cnblogs.com/blog/883541/202009/883541-20200922145314920-1666233060.png)

              对于tomcat  进行优化 
               ========    创建线程池 增大线程池数量 
                          <!--将注释打开-->
                    <Executor name="tomcatThreadPool" namePrefix="catalina-exec-"
                                  maxThreads="500" minSpareThreads="50" prestartminSpareThreads="true" maxQueueSize="100"/>

              <!--
                          参数说明：
                          maxThreads：最大并发数，默认设置 200，一般建议在 500 ~ 1000，根据硬件设施和业务来判断
                          minSpareThreads：Tomcat 初始化时创建的线程数，默认设置 25
                          prestartminSpareThreads： 在 Tomcat 初始化的时候就初始化 minSpareThreads 的参数值，如果不等于 true，minSpareThreads 的值就没啥效果了
                          maxQueueSize，最大的等待队列数，超过则拒绝请求
              -->

              <!--在Connector中设置executor属性指向上面的执行器-->
              <Connector executor="tomcatThreadPool" port="8080" protocol="HTTP/1.1"
                                   connectionTimeout="20000"
                                    redirectPort="8443" />
        
              修改连接池后重启tomcat 在观察 测试1000并发时的数据    结果是 对 1000 压力测试还是有一半 结果 还是原来的异常
              
              修改tomcat 的 运行方式
              bio
              性能非常低下，没有经过任何优化处理和支持

              nio
              nio(new I/O)，是Java SE 1.4及后续版本提供的一种新的I/O操作方式(即java.nio包及其子包)。Java nio是一个基于缓冲区、并能提供非阻塞I/O操作的Java API，因此nio也被看成是non-blocking I/O的缩写。它拥有比传统I/O操作(bio)更好的并发运行性能。Tomcat8默认使用nio运行模式。

              apr
              安装起来最困难，但是从操作系统级别来解决异步的IO问题，大幅度的提高性能

              对于每种协议，Tomcat都提供了对应的I/O方式的实现，而且Tomcat官方还提供了在每种协议下每种I/O实现方案的差异， HTTP协议下的处理方式如下表
              
              ![](https://img2020.cnblogs.com/blog/883541/202009/883541-20200922150454008-582716505.png)


      
              tomcat 中建议使用 nio  tomcat8 默认使用的nio2  所以这个修改作用不大
              <Connector executor="tomcatThreadPool"  port="8080" protocol="org.apache.coyote.http11.Http11Nio2Protocol"
           connectionTimeout="20000"
           redirectPort="8443" />
        
              调整nginx    的keepalive  
              upstream  butterfly {
                      server 127.0.0.1:8080;
                      keepalive 20;
              }

           http {
                    
                    # 设置 请求缓冲
                    client_header_buffer_size 128k;

              }
              
              设置请求缓冲中有 效果 异常信息  状态 由 49%  -->  37%  

  nginx重新 优化
              http{
                    sendfile on;
                    tcp_nopush on;
                    
                    keepalive_timeout 120;
                    tcp_nodelay on;
              }
         
  nginx  设置错误日志           在全局配置对应的错误日志信息  error_log      logs/error.log      error;


  centos 内核优化
        内核配置文件              cat /etc/sysctl.conf