Apache 2.2 CGI perl timeouts, still times out even with periodic prints.

Question

I have a cgi code that is being called by AJAX from clientside javascript. However, the result of the call is discarded by the client.

On the backend this code occurs:

$|=1;
my $i = 0;
while (<$fh_echo>)
{
    #To prevent apache timing out the cgi script. 
    print "." if $i % 100 == 0;

    #Do stuff
    $i++;
}

Despite the periodic print out, this still times out:

[warn] [client 10.23.12.87] Timeout waiting for output from CGI script 
[error] [client 10.23.12.87] (70007)The timeout specified has expired: ap_content_length_filter: apr_bucket_read() failed

I figure the fact that javascript discards the output shouldn't have any form of impact on whether or not apache allows the cgi script to continue. If so, then what is happening here?

Answer 1

Perl buffers output, please make sure $| is set to a non-zero value.

Apache will timeout the request unless you disable that functionality, whether there is something returned or not from the cgi side.