为什么Windows上的Perl的IO :: Socket抱怨“资源不可用"? 64个连接后? [英] Why does Perl's IO::Socket on Windows complain about "Resource Not Available" after 64 connections?

问题描述

我用Windows下的Perl创建了一个服务器(ActivePerl 5.10.1 build 1006)，该服务器在连接时分叉，接受一些JSON数据，并将其写入数据库. 64个客户端连接到服务器后，我遇到了问题，尝试分叉时错误消息为资源不可用".

I created a server with Perl under Windows (ActivePerl 5.10.1 build 1006) that forks upon being connected to, accepts some JSON data, and writes it to a database. I am running into a problem after 64 clients connect to the server, the error message being "Resource is not available" when trying to fork.

在Linux上运行此代码，我发现许多已失效的子进程，可以通过在父进程上添加wait()调用来解决.但是，这并不能解决问题.在Linux下运行代码的工作已经超过Windows允许的64个调用.

Running this code under Linux I found many defunct child process, which was solved by adding a wait() call on the parent. This however did not solve the problem. Running the code under Linux works past the 64 calls allowed in Windows.

如果服务器受到限制，我还会启动虚拟Windows服务器，但是重新安装Perl会导致相同的64个连接限制.

I also spun up a virtual Windows server in case it was restrictions on the server, but a fresh install of Perl resulted in the same 64 connection limit.

任何想法都值得赞赏.

use IO::Socket; 
use Net::hostent; 
use JSON;
use DBI;
use Data::Dumper;

my $port=shift || 9000;
my $clients_served = 0;

while(1){
  my $server = IO::Socket::INET->new( Proto => 'tcp', 
    LocalPort => $port, 
    Listen => 1, 
    Reuse => 1); 

  die "can't setup server" unless $server; 
  print "[Server $0 is running]\n"; 

#### 
# wait for a client to connect
# once it has, fork to a seperate thread and
# retrieve the JSON data
#### 
  while (my $client = $server->accept()) { 
    my $pid = fork();

      if ($pid != 0) {
        print ("Serving client " . $clients_served++ . "\n");
      }else{
        $client->autoflush(1); 
        my $JSONObject = JSON->new->ascii->pretty->allow_nonref();
        my $hostinfo = gethostbyaddr($client->peeraddr); 
        my $client_hostname = ($hostinfo->name || $client->peerhost);

        printf "connect from %s\n", $client_hostname;

        print " $client_hostname connected..\n";
        syswrite($client, "Reached Server\n", 2048);
        if (sysread($client, my $buffer, 2048) > 0) {

          foreach my $tasks($JSONObject->decode($buffer)){
            foreach my $task (@$tasks){
              insert_record($client_hostname, $task); #empty method, contents does not affect result
            }
          }
        }

        print " $client_hostname disconnected..\n";
        close $client; 
        exit 0;
      }
  }
  $server->close();
}

exit 0;

推荐答案

尝试从完成的交易中获取僵尸进程.我可以将您的示例代码发送给 如果再添加几行，请继续运行:

Try reaping the zombie processes from the finished transactions. I can get your sample code to keep running if I include a couple more lines:

    use POSIX ':sys_wait_h';

    if ($pid != 0) {
        print ("Serving client " . $clients_served++ . "\n");
        1 while waitpid -1, WNOHANG > 0;

如果您可能有64个同时连接，则可能不得不考虑其他问题-在Windows上安装SIGCHLD处理程序是没有好处的.

If you might have 64 simultaneous connections, you might have to think of something else -- it's no good to install a SIGCHLD handler on Windows.

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