We are using APC with compilation in one of our project, magento version is only FPC extension is installed in it.

At front-end all pages are working fine but Checkout & cart page shows 500 internal server error.

We checked error_log of server. It shows me below errors

(104)Connection reset by peer: mod_fcgid: error reading data from FastCGI server  
Premature end of script headers:index.php

Is there any way to resolve such issue.


2 Answers 2


Hesitant to comment on this as I have no proof to provide you. However.

Given that you say you are currently using APC with your PHP , i sugest you disable the magento compilation all together.

In my tests Enabling the magento compilation actually slows performance when you are already using APC or another accelerator.

Take page speed measurements before and after disabling compile, you might find it does nothing at all to your performance or that it even hurts it.

  • 1
    Code optimizations in 1.6 and later have been noted to render the compiler a moot point on A/B testing. Go for APC and eliminate another source of failure by disabling the compiler. Commented Oct 21, 2013 at 15:51
  • 1
    @Alistair & Fiasco Labs: Yes i have tested by disabling compilation, it doesn't make any difference in performance, so decided to disable compilation. Commented Oct 22, 2013 at 11:39

APC starts with PHP 5.3 to have issues, which long time were not fully fixed, and maybe still some rare occurring Bugs are still there.

With PHP 5.4, APC is nearly useless. There are a lot of companies, who skipped this version completely.
Seeing that PHP 5.5 comes with an own opcode cache leads to a state, where APC will never get fixed to be usable again.

So the clear solution is: update to a current php and use the new boundled OpCache.

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