Re: mod_perl2 + fork + DBI = Chaos

I wish I could do SQL before the fork, but I need to update tables with 
results in the forks.

Just to make things stranger, after I make a fork and things don't 
happen the way I expect them, subsequent calls to other programs running 
under mod_perl are generating Segmentation Faults.  This could be due to 
the fact that the server is running in Europe and the SQL server in 
North America.  I would really love to hear that this can cause 
segmentation faults because otherwise I have no idea where they are 
coming from and in all my years using this same framework in mp1, mp2 or 
just vanilla CGI I have never seen so many segfaults.

Bah...

Tosh


[email protected] wrote:
> Have you been through these threads already?
> The first one seems quite like what you're doing.
> 
> http://mail-archives.apache.org/mod_mbox/perl-modperl/200908.mbox/%[email protected]%3E 
> 
> http://www.gossamer-threads.com/lists/modperl/modperl/100099
> 
> Is the time for the SQL inquiry so bad that you can't
> just do the inquiry before the fork-and-exec bit?
> 
> Best of Luck,
> cmac
> 
> 
> On Jan 25, 2010, at 8:07 AM, Tosh Cooey wrote:
> 
>> My application-from-hell is doing odd things probably related to the 
>> above storms and culminating in a perfect storm.
>>
>> Can anyone point me to resources outlining the best way to use the 
>> combination in the subject line?
>>
>> There seems to be many ways of accomplishing specifics but very little 
>> generic methodologies which can be adapted.
>>
>> What I'm trying to do is in a nutshell:
>>
>> ##########
>> my $object_with_DBH = new My::DataObject;
>>
>> ... do stuff...
>>
>> if ($pid = fork) {
>>     ... parent things ...
>> } elsif (defined $pid) {
>>   ... close STDhandles ...
>>
>>   my $data = $object_with_DBH->SQL('do SQL stuff with old connection');
>>
>>   exec 'things from $data';
>>
>>   CORE::exit(0);
>> }
>> ##########
>>
>> I've tried Stas' code but that's for MP1, and with $DBI->clone(), and 
>> playing with "setsid" from POSIX and on... There seems to be no love 
>> between mod_perl2, fork, and DBI.
>>
>> On a side, but possibly related note, my browser is sending a POST 
>> request which results in the FORK above and the parent then sends a 
>> 302 redirect with some status variables.  This works fine, except 
>> between the POST and the 302 GET is another POST to the same URI which 
>> results in a 500 error, here's the log:
>>
>> "POST /tosh/mailfile.pl HTTP/1.1" 302 282
>>
>> "POST /tosh/mailfile.pl HTTP/1.1" 500 424
>>
>> "GET /tosh/index.pl?message=Notice%20sent HTTP/1.1" 200 4309
>>
>> The browser only seems to see the middle one, the 500.  I'm certain 
>> this is related to my poor forking above but I have no idea why.  Are 
>> there any tools for Firefox that will let me track every connection 
>> it's making and why?
>>
>> Thanks again for any help with my Frankenstein monster...
>>
>> Tosh
>>
>> -- 
>> McIntosh Cooey - Twelve Hundred Group LLC - http://www.1200group.com/
> 
> 

-- 
McIntosh Cooey - Twelve Hundred Group LLC - http://www.1200group.com/