We are planning to build a web based custom business analytics tool using PHP and MySQL/PostgreSQL. In our application, we are planning to upload customer’s data using a Excel sheet and these data will be displayed on custom build interactive dashboard.
I have few questions before I start working on this application
1) For the mass data upload from excel, which db is suitable MySQL or PostgreSQL?
2) At some point is it possible that multiple customers can start data upload at same time ?. To deal with such scenario is it advisable to create a separate db for each customer or to use a single db for application(single tenancy vs multi-tenancy). Please tell me pros and cons if any for each scenario?
3) How it would affect my dashboard performance, if I go with multiple databases design and I join tables across multiple databases?