[Catalyst-dev] Re: still struggling with fastcgi (Stuart Watt)

[Joseph He]

Thank you, Stuart.

Process Explorer really helps, at least I can see which script is alive,
even though I still cannot figure out it is process or thread. Here is what
I see on Process Explorer:
1. There is httpd.exe. Its command line is C:\Apache2.2\bin\httpd.exe -k
runservice
2. Under httpd.exe, there is another httpd.exe, its command line is
C:\Apache2.2\bin\httpd.exe -d C:/Apache2.2 -f C:\Apache2.2\conf\httpd.conf
-d C:\Apache2.2\.
3. Under httpd.exe mentioned in 2, there are multiple perl.exe, their
command lines are typically C:\Perl\bin\Perl.exe C:\...\fcgi-bin\index.fcgi,
etc.

## All these perl.exe seems to be process instead of thread to me 'cause its
memory usage is typically from 15M - 23M, which is a bit higher to me if it
is a thread.

I believe this is resource issue, whenever my cpu usage reaches to 100%,
problem happens. So I studied Apache configure directives and find that
MaxRequestPerChild and ThreadsPerChild are supported by mdm_winnt, no other
configuration directives are useful in windows. Below is my testing and
observation:

MaxRequestsPerChild 6
ThreadsPerChild         5

Now after clicking and clicking, on Process Explorer, I can see Apache
launches another httpd.exe under httpd.exe mentioned in 1, then the 'older'
httpd.exe and all the perl.exe under its umbrella are killed. The server
just repeated this for three days without problem. But, sorry, please bear
with me that there is still but here :)

With these two directives, perl.exe processes cannot just grow more and more
now, but I don't know how Apache counts this MaxRequestPerChild, some pages
I can refresh 30 times before new httpd.exe is launched, some others might
be 15, might be 8 or 9. Some times I can see a new server is launched with 5
perl.exe, sometimes it might happen with more that 20 perl.exe processes
running. This really puzzled me, because it is hard to optimize the server
for production, especially our clients might use different kinds of
server/hardware.

Who can explain what exactly MaxRequestPerChild and ThreadsPerChild are in
Windows environment? Apache document does not help me much here.

Really appreciate all your helps!

Joe

>
>
> Today's Topics:
>
>   1. Re: still struggling with fastcgi (Stuart Watt)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 2 Oct 2010 13:24:23 -0400
> From: Stuart Watt <stuart at morungos.com>
> Subject: Re: [Catalyst-dev] still struggling with fastcgi
> To: Development of the elegant MVC web framework
>        <catalyst-dev at lists.scsys.co.uk>
> Message-ID: <33E64D3E-4005-479A-A800-5619A90ADE59 at morungos.com>
> Content-Type: text/plain; charset=3D"us-ascii"
>
> If you see multiple processes in the Windows task manager, these will be
> distinct Perl processes rather than threads. I haven't used Apache FastCG=
I,
> but under IIS, FastCGI is a single Perl thread per worker process, and th=
is
> is likely to be the case. If you use the SysInternals process explorer (I=
'd
> strongly recommend using these tools for performance debugging in Windows)
> this will allow you to see how many threads each process is using inside.=
 So
> it sounds like Apache may be creating Windows processes on you, but I cou=
ld
> be wrong.
>
> I haven't seen this kind of an error with IIS/FastCGI, but we tend not to
> use that many worker processes. I've been using 20 worker processes at mo=
st.
>
> There are connection limits in MSSQL which could be a factor. That would =
be
> something I'd check.
>
> The 109 implies you are using named pipes to communicate between Perl and
> MSSQL. I tend to use TCP/IP. These are settings in the MSSQL Configuration
> Manager tool, and it might be worth looking to see whether changing the
> protocols might result in a different error. I'm not a low-level Windows
> expert, and there are many other resource limits you can hit in Windows
> apart from memory issues. Again, the SysInternals tools might help.
>
> Not having used Apache FastCGI that's about all I can say for now, but at
> the Perl/MSSQL boundary (which we hit even using IIS/FastCGI) these are
> issues I'd suggest looking into.
>
> All the best
> Stuart
> --
> Stuart Watt
> stuart at morungos.com
>
>
>
> On 2010-10-01, at 3:59 PM, Joseph He wrote:
>
> > It seems to be a resource issue, so it is a matter of how to configure
> Apache/Windows to better handle/allocate resources. fastCGI helps to keep
> scripts stay in cache instead of killing and loading it every time.
> >
> > My understanding is on Windows, there is only one process with many
> threads, so my assumption is if I set limit on the threads, then there
> should not be a lot of spare threads staying in the cache, thus, the syst=
em
> will not be running to resource limit.
> >
> > I add these to conf file.
> > ThreadLimit 5
> > ThreadsPerChild 5
> >
> > Unfortunately, on windows process monitor, I still see the number of Pe=
rl
> processes just goes up and up with my clicking and then give me error when
> it reaches some level. This is not a striking test yet, just clicking 40
> different pages by myself can exhaust all the resources ....
> >
> > On 29 September 2010 22:15, Joseph He <joseph.he.2008 at gmail.com> wrote:
> >
> > > Thank you, T0m. Actually it is 5.8.7.
> > >
> > > I have done more testing while having windows Tast Manager open. I fi=
nd
> o=3D
> > ut
> > > that these issues only happen when I already have about 35-38 Perl
> proces=3D
> > ses
> > > running. Mainly two types of errors:
> > >
> > > 1. [Wed Sep 29 15:06:11 2010] [error] [client 127.0.0.1] (OS 109)The
> pipe
> > > has been ended.  : FastCGI: comm with server "C:.....fcgi" aborted:
> > > GetOverlappedResult() failed, referer ......
> > >
> > > ## I searched and know that "(OS 109)The pipe has been ended" is SQL
> serv=3D
> > er
> > > error message.
> > >
> > > 2. [Wed Sep 29 15:10:52 2010] [error] [client 127.0.0.1] FastCGI:
> server
> > > "C:......fcgi" stderr: install_driver(ODBC) failed: Can't load
> > > 'C:/Perl/site/lib/auto/DBD/ODBC/ODBC.dll' for module DBD::ODBC:
> load_file=3D
> > :A
> > > dynamic link library (DLL) initialization routine failed at
> > > C:/Perl/lib/DynaLoader.pm line 230., referer: ....
> > > #
> >
> >
> > Sounds like an out of memory condition triggering a problem. What does
> the
> > Windows monitor show with respect to memory usage?
> > I have seen random errors from FastCGI on Linux, too, which aren't all
> that
> > easy to track down.
> > How about trying it through an Apache server on Windows and see if that
> > works or gives more information.
> > Or running your app on Linux if that's an option.
> >
> > Regards, Peter
> > http://perl.dragonstaff.co.uk
> >
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.scsys.co.uk/pipermail/catalyst-dev/attachments/20101008/e=
c4db1d2/attachment.htm