Description:
------------
When connecting to a database, then forking off a new child, the database connection will be terminated (disconnected) when the child exits.

I have the feeling that at the "cleanup" of the child process the database connection is closed. This should not be the case because the master process might still use it.

This is not the case with the mysql extension, only with mysqli. With the mysql extension, you might be required to give the optional parameter "open new session" on the connect. at least this is what I did.

Reproduce code:
---------------
<?php

function ping_db( $res, $msg )
{
  if ( mysqli_ping($res) )
    echo getmypid()." $msg: still alive\n";
  else
    echo getmypid()." $msg: died\n";
}

function SigChild( $signal )
{
  while ( ($pid=pcntl_wait($status,WNOHANG)) > 0 ) {
    if ( !pcntl_wifexited($status) )
      echo "Collected killed pid $pid\n";
    else
      echo "Collected pid $pid\n";
  }
}

declare(ticks=1);
pcntl_signal( SIGCHLD, 'SigChild' );

$res = mysqli_connect('localhost','zpc','zpc');
ping_db($res,'after connect');

$pid = pcntl_fork();
ping_db($res,'right after fork');

if ( !$pid ) {                  // --- the slave
  echo "child sleep\n";
  sleep(5);
  echo "child exiting\n";
  exit(0);
}

ping_db($res,'after fork');

echo "master sleep\n";
sleep(10);
ping_db($res,'after sleep');

while ( ($pid=pcntl_wait($status)) > 0 ) {
  if ( !pcntl_wifexited($status) )
    echo "Collected killed pid $pid\n";
 else
    echo "Collected pid $pid\n";
}

mysqli_close( $res );

?>


Expected result:
----------------
The database connection in the master should not have terminated.

Actual result:
--------------
6311 after connect: still alive
6313 right after fork: still alive
child sleep
6311 right after fork: still alive
6311 after fork: still alive
master sleep
child exiting
Collected pid 6313
6311 after sleep: died

In the last line you can see that the connection died (6311 is master, 6313 is child)