>
> > Here's pseudo code for what I'm trying to do:
> >
> > foreach ($things as $thing) {
> > info = getInfo($thing); // uses a db connection
> > makeApiCall(info);
> > }
> >
> > makeApiCall(info) {
> > $pid = pcntl_fork();
> > if ($pid == -1) {
> > die("could not fork");
> > } else if ($pid) {
> > // parent, return the child pid
> > echo "child pid $pid\n";
> > return;
> > } else {
> > // do some api calls
> > exit;
> > }
> > }
> >
> > But after I spawn off the process, getInfo($thing) errors out sometime
> > later on with an "invalid query" error, because I think the db
> > connection is gone. I thought adding "exit" in the child process
> > would be enough, but that doesn't seem to work, I still get the same
> > error. Why would the child process affect the query in the parent
> > process, especially if I exit in the child process?
>
> First things first - I would add a pcntl_wait like this:
>
> foreach ($things as $thing) {
> info = getInfo($thing); // uses a db connection
> makeApiCall(info);
> switch( $p=pcntl_wait( $stat, WNOHANG ) )
> {
> case -1: echo "some sort of error in pcntl_wait()\n"; break;
> case 0: break;
> default:
> echo "child $p finished\n";
> }
> }
>
I actually tried this in the meantime:
$pid = pcntl_fork();
if ($pid == -1) {
die("could not fork");
} else if ($pid) {
// parent, return the child pid
echo "child pid $pid waiting\n";
pcntl_waitpid($pid, $status);
if (pcntl_wifexited($status)) {
echo "finished [$status] waiting\n";
return;
} else {
echo "ERROR\n";
}
But it still has the same problem, and I'm also trying to avoid pcntl_wait
or pcntl_waitpid at all because I still want to do it asynchronously. I
even tried rewriting it do return $pid in the parent thread, and then
aggregate them at the calling function level, and then loop through them all
with pcntl_waitpid, but that didn't work either.
>
>
> Second, it sounds like you're expecting to reuse your database
> connection from getInfo() in the child you're forking in makeAPIcall()?
> I don't think that really works - I think you need a new connection per
> child.
>
Oh, in this case, I don't do anything with the database at all in the child
thread. I was worried there would be some errors there so I actually
commented out all db accesses in the child thread, but it still somehow
closes the parent's db connection (or at least causes the query not to work,
somehow).
