Finding a Function in a website

I have a function or number of functions that are running at a certain time during each day which is bringing the site down. What is easiest way to search through my thousan开发者_开发知识库ds of custom and default functions which come with Wordpress so that I can reduce the manual time on my end to find these errant functions?

few ways to tackle this

1. mysql - enable mysql slow query logging
2. apache - enable mod_status with ExtendedStatus On, and prepare a crontab to log the apache process around 6am
3. linux - use another crontab to log activity captured by ps afx during that 6am time span

Maybe you could use http://www.php.net/debug_backtrace (together with http://www.php.net/set_error_handler )to implement some logging.