Re: Apache2 PHP mod_fcgi HTTP 500 errors

Stefan,

php seems to restart its children automatically from time to time, I suspect as 
a way to get reclaim memory from leaks.  Is it possible the problem is due to 
the php process not completing its work when it receives the SIGTERM?

David.

-----

On Mon, 24 Oct 2005, Stefan Wendt wrote:

> Hi All,
>
> Any type of  help on the following problem would be greatly appreciated.
>
> We thought everything is running smoothly until a few days ago. We discovered
> a few HTTP 500 errors in the access log file. The additional PHP error log 
> file
> did not show any error message. So we ruled out a problem with the 
> application.
> The problem occurs sporadic a few times each day since we installed the 
> server with
> the required FCGI components.
>
> We currently using the following components on our server:
>
> Apache/2.0.54 (Debian GNU/Linux)
> mod_fastcgi/mod_fastcgi-SNAP-0404142202
> mod_suexec.so
> PHP 4.4.0
> (please note: all! configuration values for mod_fcgi and php_cgi are set to 
> default
> except for PHP_FCGI_CHILDREN=10)
>
> It's hard to reproduce the problem, but putting heavy http load on the server 
> produces
> the problem more frequently.
>
> I searched this mailing list and there seam to be similar cases, but none of 
> the answers
> really solve the problem. Deploying fcgid seams to be the common fix, but I 
> am
> not willing to give up on mod_fcgi just yet.
>
> I spend a lot of time last week figuring out what the root cause is and this 
> is what I have:
>
> I think the information below shows quite clearly that the fcgi-pm(?) 
> terminates the
> php process while 2 of it's child processes still work on a request.
>
> Thanks for having a look into this ...
>   Stefan Wendt
>
> PS before failure
> ---
> test     10414  0.0  0.3 10552 3616 ?        Ss   10:34   0:00  |   \_ 
> /usr/local/php_fcgi_4.4.0/bin/php
> test     21061  8.5  0.9 14996 8748 ?        S    11:01   0:12  |   |   \_ 
> /usr/local/php_fcgi_4.4.0/bin/php
> [... 9 more lines ]
> test     17287  0.0  0.3 10556 3620 ?        Ss   10:54   0:00  |   \_ 
> /usr/local/php_fcgi_4.4.0/bin/php
> test     17288  7.7  0.9 15004 8760 ?        S    10:54   0:44  |   |   \_ 
> /usr/local/php_fcgi_4.4.0/bin/php
> [... 9 more lines ]
>
> Apache Access Logfile:
> ---
> [...]
> 81.169.x.x - - [24/Oct/2005:11:04:24 +0100] "GET 
> /hotels/Test/bookings/client.php?formname=multi_day_availability HTTP/1.0" 
> 200 49901 "-" "ApacheBench/2.0.41-dev"
> 81.169.x.x - - [24/Oct/2005:11:04:24 +0100] "GET 
> /hotels/Test/bookings/client.php?formname=multi_day_availability HTTP/1.0" 
> 500 698 "-" "ApacheBench/2.0.41-dev"
> 81.169.x.x - - [24/Oct/2005:11:04:24 +0100] "GET 
> /hotels/Test/bookings/client.php?formname=multi_day_availability HTTP/1.0" 
> 500 698 "-" "ApacheBench/2.0.41-dev"
> [...]
>
> global Apache Error Logfile:
> ---
> [Mon Oct 24 11:04:24 2005] [warn] FastCGI: (dynamic) server 
> "/home/test/test.avvio.com/php-fcgi/php-fcgi-starter" (pid 17287) termination 
> signaled
> [Mon Oct 24 11:04:24 2005] [warn] FastCGI: (dynamic) server 
> "/home/test/test.avvio.com/php-fcgi/php-fcgi-starter" (pid 17287) terminated 
> by calling exit with status '0'
>
>
> Trace of the PHP mother processes:
> ---
> somehost:~# strace -p 17287
> Process 17287 attached - interrupt to quit
> wait4(-1, 0xbfd44944, 0, NULL)          = ? ERESTARTSYS (To be restarted)
> --- SIGTERM (Terminated) @ 0 (0) ---
> rt_sigaction(SIGTERM, {SIG_DFL}, NULL, 8) = 0
> kill(-17287, SIGTERM)                   = 0
> --- SIGCHLD (Child exited) @ 0 (0) ---
> exit_group(0)                           = ?
> Process 17287 detached
> ds80-237-153-8:~#
>
> PS after failure:
> ---
> test     10414  0.0  0.3 10552 3616 ?        Ss   10:34   0:00  |   \_ 
> /usr/local/php_fcgi_4.4.0/bin/php
> test     21061  8.7  0.9 14996 8748 ?        S    11:01   0:14  |   |   \_ 
> /usr/local/php_fcgi_4.4.0/bin/php
> [... 9 more line ]
>
>
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>

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