PHP pcntl multi-process usage example

The example in this article describes the usage of PHP's pcntl multi-process. Share it with everyone for your reference. The specific analysis is as follows:

PHP can also process a transaction with multiple processes using the PCNTL series of functions. For example, I need to obtain 800,000 pieces of data from the database and then perform a series of subsequent processing. At this time, should I use a single process? You can wait until today next year. So you should use the pcntl function.

Suppose I want to start 20 processes and divide 1-80w of data into 20 parts. The main process waits for all sub-processes to finish before exiting:

$max = 800000;
$workers = 20;
$pids = array();
for($i = 0; $i < $workers; $i++){
  $pids[$i] = pcntl_fork();
  switch ($pids[$i]) {
    case -1:
      echo "fork error : {$i} \r\n";
      exit;
    case 0:
      $param = array(
        &#39;lastid&#39; => $max / $workers * $i,
        &#39;maxid&#39; => $max / $workers * ($i+1),
      );
      $this->executeWorker($input, $output, $param);
      exit;
    default:
      break;
  }
}
foreach ($pids as $i => $pid) {
  if($pid) {
    pcntl_waitpid($pid, $status);
  }
}

Here when pcntl_fork comes out, it will return A pid value. This pid is 0 when viewed in the child process, and is the pid of the child process (>0) when viewed in the parent process. If the pid is -1, it means that a fork error occurred.

Using a $pids array allows the main process to wait for all processes to complete before ending it

I hope this article will be helpful to everyone's PHP programming design.

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