I have to develop a high-end application (which would provide a lookup service like superpages.com) for my client. I am considering using either php/mysql or C/mysql combination.

The service would be for a very high traffic site which would perhaps run on a combination of around 4-5 servers under a load balanced setup. (i.e. my client is estimating that kind of traffic and we need to develop the application based on his requirements and estimation). The entire database size may be around 10 GB.

Since the traffic would be high and mysql database activity would be continous, would it make sense to make the application in php or c/c++ for greater speed and lesser server loads.

I believe that many high end search engines run on programs developed in "C".

An inputs would be appreciated.