记一次JMeter内存不足

问题背景

• 压测的业务存在多个返回情况，其中认为true的response有两种，认为false的有三种，具体如下
  
• 需要在jmeter.log中记录下Assert false时的线程信息，如当前活跃的线程数
• 需要把exception的信息和error的信息分别保存到文件中

问题描述

• 这种背景下只能选择BeanShell来处理断言、保存信息以及打印特定log了，于是有了下面第一版beanshell

  import com.alibaba.fastjson.JSON;  // 阿里的jar包
  import com.alibaba.fastjson.JSONObject;
  import java.util.Date;
  import java.text.SimpleDateFormat;
  
  void write2File(String data, String path){
      // 该方法用来写入内容到文件，并加上时间
      String tm = (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS")).format(new Date());
      FileWriter fstream = new FileWriter(path, true); //FileWriter("file01.txt",true) append mode
      BufferedWriter out = new BufferedWriter(fstream);
      out.write("[" + tm + "] " + data);
      out.write(System.getProperty("line.separator"));
      out.close();
      fstream.close();
  }
  
  if ("200".equals(""+ResponseCode) == false ){
      var errorFile = "errorFile.txt";
      write2File(prev.getResponseDataAsString(), errorFile);  // 写入error信息到errorFile.txt
      Failure=true ;  // 设置断言为false
      FailureMessage ="Exception,fail! Response code is " + ResponseCode;  // 设置断言message
      // 打印log，ctx.getThreadNum()代表当前线程，ctx.getThreadGroup().getNumThreads()代表当前活跃的总线程数
      log.warn(FailureMessage + ". Current threadNum is " + ctx.getThreadNum() + " of " + ctx.getThreadGroup().getNumThreads());
  }else{
      var respBody = prev.getResponseDataAsString();
      // 因为response是JSON格式，这里用JSON包处理
      JSONObject respJson = JSON.parseObject(respBody);
      if (respJson.containsKey("data")){
          Failure=false;
          FailureMessage = "Return true, and the response code was " + ResponseCode;
      }else if (respJson.containsKey("x")){
          var x = respJson.getString("x");
          if (x.contains("connection issue")){
              var issueFile = "issueFile.txt";
              write2File(x, issueFile);
              Failure= true;
              FailureMessage= "connection issue,fail!";
              log.warn(FailureMessage + " Current threadNum is "+ ctx.getThreadNum() + " of " + ctx.getThreadGroup().getNumThreads());
          }else{
              var exceptionFile = "exceptionFile.txt";
              write2File(x, exceptionFile);
              Failure=false;
              FailureMessage = "Return exception, and the response code was " + ResponseCode;
          }	
      }else{
          Failure= true;
          FailureMessage= "Unknow error: " + respBody;
          log.warn(FailureMessage + ". Current threadNum is "+ ctx.getThreadNum() + " of " + ctx.getThreadGroup().getNumThreads());
      }
  }
  

• 本地调试正常，开心的推到负载机上执行，但是压测时总会出现“内存转储”的现象，即生成hprof文件，比如java_pid3736.hprof
• 既然内存不足，那就增加JVM内存嘛，于是修改了JMeter启动文件设置

  set HEAP=-Xms1g -Xmx1g -XX:MaxMetaspaceSize=256m
  

• 发现还是会内存不足，那就分析下转储文件吧（用Memory Analyzer分析）
  
  • 问题很明显了，beanshell内容开销过大

尝试解决

1. 把if判断改成switch：不记得从哪个大神那里看来的说switch比if节省资源
2. 把写信息到文件的操作去掉

   import com.alibaba.fastjson.JSON;
   import com.alibaba.fastjson.JSONObject;
   
   switch (ResponseCode){
       case "200":
           var respBody = prev.getResponseDataAsString();
           JSONObject respJson = JSON.parseObject(respBody);
           int f = respJson.containsKey("x") ? 0:1;
           switch (f){
               case 1:
                   Failure=false;
                   FailureMessage = "Return true, and the response code was " + ResponseCode;
                   break;
               case 0:
                   var x = respJson.getString("x");
                   if (x.contains("connection issue")){
                       Failure= true;
                       FailureMessage= "connection issue,fail!";
                       log.warn(FailureMessage + " Current threadNum is "+ ctx.getThreadNum() + " of " + ctx.getThreadGroup().getNumThreads());
                   }else{
                       Failure=false;
                       FailureMessage = "Return exception, and the response code was " + ResponseCode;
                   }
                   break;
               default:
                   Failure= true;
                   FailureMessage= "Unknow error: " + respBody;
                   log.warn(FailureMessage + ". Current threadNum is "+ ctx.getThreadNum() + " of " + ctx.getThreadGroup().getNumThreads());
                   break;
               }
           break;
       default:
           Failure=true;
           FailureMessage ="response error, code was" + ResponseCode;
           log.warn(FailureMessage + ". Current threadNum is " + ctx.getThreadNum() + " of " + ctx.getThreadGroup().getNumThreads());
           break;
    }
   

3. 再次执行就没有问题了