Please try using this CVS snapshot:

  http://snaps.php.net/php5.2-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php5.2-win32-latest.zip

No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

I am also able to reproduce this on the current 5.2 branch (built: May 27 2006 16:22:11) with isapi_fcgi.dll (FCGI_SERVER_VERSION = 2.2.2 0.5.2 beta).  It appears to be triggered by an echo that is larger than some magic number around 16kB.  This code:

<?php
	echo str_repeat(str_repeat("-=-=-=", 20) . "<br>", 131);
?>

outputs a page that is 16,244 bytes.  If I increase the count to 132 (what would be 16,368 bytes) I get:

"HTTP/1.1 503 Server too busy
Server: Microsoft-IIS/5.1
Date: Sat, 27 May 2006 15:05:07 GMT
X-Powered-By: ASP.NET
Connection: close
Content-Type: text/html

Server Error, unable to connect to fastcgi server."

The bug does seem to go away with the 5.2 version.

I am also able to reproduce the behavior described by msisolak exactly.

Please try using this CVS snapshot:

  http://snaps.php.net/php5.2-latest.tar.gz
 
For Windows:
 
  http://snaps.php.net/win32/php5.2-win32-latest.zip

No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".

I can verify the above experiment.  I got the 5.2 snapshot and used the following:

<?php
	echo str_repeat(str_repeat("-=-=-=", 20) . "<br>", 131);
?>

That works fine.  But change the 131 to 132 and you get the 503 error.  At a loss.
dave

Some more information( hopefully useful ).

After further testing I was able to determine that this is only happening for me if I output a lot of text at once.  If I split it up into a bunch of smaller echo's, it works fine.

Unfortunately this doesn't work with my template system, as all output is echoed in one statement.
dave

Hello, I confirm, still no go with latest snapshot
 - 5.2.0RC4-dev, Build Date Sep 7 2006 00:15:28  

I tried phpinfo() with CGI only, go
Tried the same with isapi_fcgi.dll, no go

Then I changed output_buffering=1000 and... GO! :)

(Windows 2003 server SP1)

I tested it with my app, output_buffering doesn't workaround the problem fully. Bigger output still harmes the fastcgi.

I'm sorry for spamming, but I went a step further, downgraded to PHP Version 5.1.0-dev and the FastCGI has no problem.
Build date Jun 21 2005 12:21:48

I am requesting that this bug status be changed to "open" since there has been plenty of feedback and until the bug has been confirmed to be fixed. 

I have also run into this same issue with php > 5.1.4 including the latest 5.1 snapshot.  My solution was to use 5.1.2 instead.

I confirmed the problem using msisolak's test on a Win 2003 server with PHP 5.1.6 running under fastcgi. Same on a Windows 2000 server with same PHP config.

I have the same problem using Windows 2003 SP1 and PHP 5.1.6

I tried the output buffering = 1000 and no luck either.

please fix!

With PHP 5.2.0RC6-dev (Oct 19 2006 20:17:20) on WinXP-SP2

<?php
echo str_repeat("-", 16340); // ok 
echo str_repeat("-", 16341); // 503 Server too busy 
?>

Still having trouble on Windows 2003 with 5.2 (stable)! (See my previous comment for details)

open - issue still exists.

This is not a PHP but isapi_fcgi.dll fault.

From quick look into source code fcgi_server.c:373 I see a buffer overflow.

            contentLength = (Header.contentLengthB1 << 8) + 
Header.contentLengthB0;// + Header.paddingLength;
            rcvd = OS_Read(req_info->appServerSock,
(char *)&work_buffer, contentLength + Header.paddingLength);

work_buffer is declared as "char work_buffer[8192]" so in case if packet length is larger then 8192 bytes isapi_fcgi.dll makes fault. According to FastCGI specification it is legal to use packets up to 65535 bytes, so this is definitely isapi_fcg.dll's problem.