Hi, 

we would need to store some additional information that comes from an external system, some IDs that we would need to search later based on user input.

We would have around 5 million entries that contain of 2 numbers (mapping) 

Could custom objects handle so big data set or is it better to have a dedicated DB for that? We are mostly worried about the performance when we need to search for an entry based on a number 

Regards, 
Drazen