Our experience is that 5.8.0 has had some changes with regard to locking. In 5.6, you were always gauranteed an flock, unless there was some monumental fatal error -- it just took a long time sometimes.

In 5.8, the new functionality seems to be that if it can't get the lock in a reasonable time-frame, it throws EINTR, and then wants you to try again later.

For the Interchange project, here is what they did (it seems to solve the problem for us): 

sub flock_lock {
    my ($fh, $excl, $wait) = @_;
    my $flag = $excl ? $flock_LOCK_EX : $flock_LOCK_SH;

    if ($wait) {
    my $trylimit = $Vend::Cfg->{Limit}{file_lock_retries} || 5;
    my $failedcount;
        while (
                ! flock($fh, $flag)
                    and
                $failedcount < $trylimit
               )
        {
           $failedcount++;
           select(undef,undef,undef,0.05 * $failedcount);
        }
        die "Could not lock file after $trylimit tries: $!\n" if ($fai
+ledcount == $trylimit);
        return 1;
    }
    else {
        if (! flock($fh, $flag | $flock_LOCK_NB)) {
            if ($!{EAGAIN} or $!{EWOULDBLOCK}) {
                return 0;
            }
            else {
                die "Could not lock file: $!\n";
            }
        }
        return 1;
    }
}

[download]
-Dan

In reply to Re: Can flock occasionally fail on systems that support file locking? by danb
in thread Can flock occasionally fail on systems that support file locking? by rzward

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