My website is operated by PHP engine version 4.0.6 working with Apache webserver version 1.3.26, run on a Solaris 2.8 host computer. PHP was compiled as a shared module.

I have been monitoring the Apache server log, and I am seeing cases where the response to a PHP request is an http status "200" with an http body size of "-", occurring 5 to 6 times daily. This is because the PHP engine did not return a response within the Apache server timeout period of 5 minutes while attempting to parse the PHP script. But, I can't figure out why the PHP script parsing routine is not returning.

I've inserted syslog() statements in the source code of the PHP engine, in the send_php(), apache_php_module_main(), php_execute_script(), zend_execute_scripts() functions to find out the reason. The resulting log shows that the source code executed until apache_php_module_main() but no further. Therefore, the problem seems to be in php_request_startup() executed before php_execute_script(), but I was unable to pinpoint the culprit.

Also, I've noticed that there was not a single occurrence where the apache process crashed(due to a segmentation fault for example), as a result of this problem.

Any help will be greatly appreciated.