error log not reflect the problem related log

[Maxim Dounin]

Hello!

On Wed, Mar 21, 2012 at 12:33:34AM -0400, niraj wrote:

> Hi
>      I am using the application which having code in perl. I have both
> html and cgi files.
> 
> For Cgi and perl files I have install the fcgi and spawn-fcgi and
> configure the same in Nginx configuration.

What do you mean by "fcgi" here?  Perl cgi files aren't able to 
talk via the FastCGI protocol, you either have to change them to 
use the FastCGI protocol (e.g. by using FCGI perl module), or need 
some wrapper which will do fastcgi to cgi protocol conversion.

(Note well that spawn-fcgi isn't a fastcgi/cgi wrapper, it's just a 
simple helper program to start multiple processes of a fastcgi 
application.)

In theory fastcgi allows to pass errors from an application to 
server via special FCGI_STDERR stream (and nginx will log such 
errors into it's error log at 'error' level with "FastCGI sent in 
stderr" prefix).  Though in practice this requires fastcgi 
application to properly redirect errors into the stream in 
question, and this isn't always done properly.

Maxim Dounin