[pmwiki-users] Best installation choices for PmWiki on Win2000 with IIS5?

Hartl, Bob hartl.r at ghc.org
Thu May 4 18:30:11 CDT 2006

Concerning whether or not PHP and its libraries are "thread-safe"...

I installed PHP 4.4.2 on Win2000/IIS using ISAPI -- and the first thing
I did was to run the suggested php script that calls phpinfo().  The
phpinfo page I got back was a long list of "settings" which included
"Thread Safety = enabled."
1) Does this mean that everything included with the PHP 4.4.2 install
package (including extensions that were included with the install
package) is "thread safe?"
2) I assume other extensions (not included in the install package) might
not be thread safe, correct?
3) Since the PHP core engine I'm using is thread safe, does this mean it
would object -- flag as an error -- an extension that wasn't "thread
4) By libraries do you mean extensions -- or are they two different
things?  (I'm an ASP/VBScript guy, so PHP and its terminology is still
new to me.)

Thanks Joachim, you've been a big help.

R. Hartl

-----Original Message-----
From: pmwiki-users-bounces at pmichaud.com
[mailto:pmwiki-users-bounces at pmichaud.com] On Behalf Of Joachim
Sent: Wednesday, May 03, 2006 10:15 PM
To: pmwiki-users at pmichaud.com
Subject: Re: [pmwiki-users] Best installation choices for PmWiki on
Win2000 with IIS5?

Hartl, Bob schrieb:
> You convinced me to avoid FastCGI, at least until it becomes a more
 > mature product.

Don't hold your breath. It seems to have gone inactive - the last stable

release was on Nov 2003, and the last snapshot release was sometime 
early 2004.

I don't consider this a problem for Apache 1.3, since it seems to work 
well there. However, on Apache 2, there are issues with zombie processes

that don't get terminated and fill up RAM until the server goes down 
thrashing. (I heard this is related to signal-handling issues, and 
suspect this will happen if too many visitors abort page loads, but 
frankly, I don't know - I just had to restart Apache several times in 
the weeks since I installed mod_fastcgi, and will back out of that as 
soon as I can.)

I haven't tested mod_fcgid yet, but at least it's under active 
development (the latest release is just two weeks old).

> Within IIS, I will 'isolate' the PMWiki app in its own process, given 
> that PHP/ISAPI might be unstable.

Seems like a good strategy.

 > But perhaps the potential instability depends on the
> PMWiki PHP scripts -- and possibly PMWiki might do well with 

One of the things to watch out is that the libraries that PHP is using 
might not be thread-safe. So things might be working smoothly for a long

time, until you install an upgrade or a new script that makes PHP use 
new library functions which happen to be thread-unsafe, at which point 
the scripts will break under any serious load.
Not a serious issue in itself, but I'm feeling uneasy at planting 
potential timebombs in my installation. When it finally explodes, I 
might have forgotten it's there, and have trouble diagnosing the 
problems correctly.


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