1=head1 NAME
2
3Debugging mod_perl Perl Internals
4
5=head1 Description
6
7This document explains how to debug Perl code under mod_perl.
8
9Most of the L<mod_perl 1.0 debug
10documentation|docs::1.0::guide::debug> applies to mod_perl 2.0:
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12
13
14
15
16=head2 Detecting Hanging Processes
17
18See L<Hanging Processes: Detection and
19Diagnostics|docs::1.0::guide::debug/Hanging_Processes__Detection_and_Diagnostics>
20for the explanation, but under mp2 to use signals to detect where the
21process is spinning, you can't use C<$SIG{USR2}>, you have to use
22POSIX signals. i.e. the code becomes:
23
24  use Carp ();
25  use POSIX qw(SIGUSR2);
26  my $mask      = POSIX::SigSet->new( SIGUSR2 );
27  my $action    = POSIX::SigAction->new(\&tell_where_spinning, $mask);
28  my $oldaction = POSIX::SigAction->new();
29  POSIX::sigaction(SIGUSR2, $action, $oldaction );
30
31  sub tell_where_spinning {
32      Carp::confess("caught SIGUSR2!");
33  };
34
35and then:
36
37  % kill USR2 <pid_of_the_spinning_process>
38
39and watch for the trace in F<error_log>.
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41
42
43
44
45=head1 Maintainers
46
47Maintainer is the person(s) you should contact with updates,
48corrections and patches.
49
50=over
51
52=item *
53
54Stas Bekman [http://stason.org/]
55
56=back
57
58=head1 Authors
59
60=over
61
62=item *
63
64Stas Bekman [http://stason.org/]
65
66=back
67
68Only the major authors are listed above. For contributors see the
69Changes file.
70
71=cut
72