What is the safe way to use fork with Apache::DBI under mod_perl2?
- by codeholic
I have a problem when I use Apache::DBI in child processes. The problem is that Apache::DBI provides a single handle for all processes which use it, so I get
DBD::mysql::db selectall_arrayref
failed: Commands out of sync; you
can't run this command now at
/usr/local/www/apache22/data/test-fork.cgi
line 20.
Reconnection doesn't help, since Apache::DBI reconnects in all processes, as I understood the following error
The server encountered an internal
error and was unable to complete your
request.
Error message: DBD driver has not
implemented the AutoCommit attribute
at
/usr/local/lib/perl5/site_perl/5.8.9/Apache/DBI.pm
line 283. ,
Here's the origin code:
use Data::Dumper 'Dumper';
use DBI ();
my $dbh = DBI->connect($dsn, $username, $password, {
RaiseError => 1,
PrintError => 0,
});
my $file = "/tmp/test-fork.tmp";
my $pid = fork;
defined $pid or die "fork: $!";
if ($pid) {
my $rows = eval { $dbh->selectall_arrayref('SELECT SLEEP(1)') };
print "Content-Type: text/plain\n\n";
print $rows ? "parent: " . Dumper($rows) : $@;
}
else {
my $rows = eval { $dbh->selectall_arrayref('SELECT SLEEP(1)') };
open FH, '>', $file or die "$file: $!";
print FH $rows ? "child: " . Dumper($rows) : $@;
close FH;
}
The code I used for reconnection:
...
else {
$dbh->disconnect;
$dbh = DBI->connect($dsn, $username, $password, $attrs);
my $rows = eval { $dbh->selectall_arrayref('SELECT SLEEP(1)') };
open FH, '>', $file or die "$file: $!";
print FH $rows ? "child: " . Dumper($rows) : $@;
close FH;
}
Is there a safe way to use Apache::DBI with forking? Is there a way to make it create a new connection perhaps?
