apache 2.2 - Can undefined variables and notices cause a cpu spike?

We're running centos 6.7, PHP 5 and MySQL 5.5 and Apache 2.2.15. Sometimes we see high CPU usage, mainly caused by MySQL so we take all the logs we can get. We're addressing MySQL optimization separately, this question is about PHP and apache mainly.

In apache error log, we keep seeing undefined variables, notices, and warnings. Every few thousand requests or more apache seems to restart.

Two questions:

• Do Apache errors cause apache to restart at some point?


• Do they cause high CPU usage, at some point?

The error log can be found here, will expire in a week.

I found a strange entry

Not sure what Microsoft's IIS has to do with the log file.