java - Simple web server when high-concurrency is met -


this not homework, interview question found on web.

the java code is:

public class simplewebserver{   public static void handlerequest(socket c)   {     //process request   }    public static void main(string[] args) throws ioexception   {      serversocket server=new serversocket(80);     while(true)     {        final socket connection=server.accept();        runnable task=new runnable(){           @override           public void run()           {             handlerequest(connection);           }        };        new thread(task).start();     }   } }

the question potential issue there when there high concurrency? analysis :

  1. it didn't use synchronized keyword, there might situations race-condition happen.
  2. it should use thread pool, more efficient.
  3. it seems each incoming thread, class creates new serversocket, consume lot of space when high-concurrency happens?

the main problem see this, 1 you've identified. thread-per-request model inherently flawed (as evidenced widescale adoption of nginx , lighttpd on apache). moving executorservice (probably backed thread pool) choice here.

by changing thread-per-request simple submission of task executorservice, moving application towards event-based model. there's lot of material out on web preaching scalability virtues of event-based on thread-based models.

using 'synchronized' on handlerequest method pretty brute-force tactic, , depending on particular guts of method more granular locking strategy (or lock-free logic) preferred. serversocket creation mentioned happens once application, that's not scalability problem. accept method create new socket instance each connection, these cheap. looking @ jdk 6 source, consists of allocating 7 booleans, lock object, , checking internal state - i.e., not going problem.

basically, you're on right track! hope helps.


Comments

Post a Comment

Popular posts from this blog

jquery - How can I dynamically add a browser tab? -

since using iframes house external pages are, accounts "not preferred method" , disallowed sites (flickr, one), want dynamically generate browser tabs. e.g., when user submits form, want dynamically generate tab on browser in response submitted. e.g., might want add new tab url like: http://www.bigsurgarrapata.com/contact how in jquery? you want form target attribute action attribute. http://www.w3schools.com/tags/att_form_target.asp browsers have ultimate control on result of target attribute open new tab value of _blank. <form action="contact_submit.php" target="_blank" method="post">
Read more

keyboard - C++ GetAsyncKeyState alternative -

i using windows.h library's getasynckeystate function define key pushed on keyboard . here program returns int value of pushed key example. #include <iostream> #include <windows.h> using namespace std; int main (){ char i; for(i=8;i<190;i++){ if(getasynckeystate(i)== -32767){ cout<<int (i)<<endl; } } return 0; } but trying make opengl simple game , function appeared slow . there function not need cycle 180 times , if statement . thanks you're trying make opengl game, you're going use glfw. if that's case can away using glfwgetkey() such: if (glfwgetkey(glfw_key_up) == glfw_press) {...} if (glfwgetkey(glfw_key_down) == glfw_press) {...} that method nicely explained in tutorial 6 opengl-tutorial.org . should start first tutorial of beginners tutorials , later intermediate tutorials . if you're going make win32 window can listen wm_keydown or wm_keyup messages , virtua...
Read more

android - java.net.UnknownHostException(Unable to resolve host “URL”: No address associated with hostname) -

i developing app testing asp.net webservice in android.for simple webservice adding 2 numbers used.where numbers passed parameters.the result in dialogue.the webserver works in local. when application runs following result exception.i provided internet permission in manifest. java.net.unknownhostexception(unable resolve host “ http://url.com/ ”: no address associated hostname) my code given below main activity public static string rslt=""; /** called when activity first created. */ @override public void oncreate(bundle savedinstancestate) { super.oncreate(savedinstancestate); setcontentview(r.layout.activity_main); button b1=(button)findviewbyid(r.id.button1); final alertdialog ad=new alertdialog.builder(this).create(); b1.setonclicklistener(new onclicklistener() { @override public void onclick(view arg0) { // todo auto-generated method stub try { ...
Read more