Big data table processing with RDBMS like MySQL?
Basically you are talking about performance. There are so many factors/parameters responsible for performance. With no doubt 100 million records are feasible in RDBMS, it depends upon configuration you have made for your server. If we look for some parameters be like :

1) Hardware : Looking into your physical table size, proper RAM allocation is done or not. For feasible amount of RAM proper CPU cores are divided or not.

( Specifically of MySQL ) 

2) Sort Buffer : Whether optimal values are configured for Sort buffer global variables.

3) Temporary Table Size : Temporary table size should be suitable enough

4) Join Buffer : Join buffer should be configured with optimal value.

And many more parameters need to look in.

Hope this helps.