I have to build a website that store a lot of data. I search in the Internet to decide whether to use relational or non relational database. I can't find a good answer. Some website say that if you have a lot of data you can choose non relational database, but I think this is not a good strategy. Facebook (for example) use relational database (mysql) although there are a lot of data that is stored in Facebook database. Other website say that if your data can be organized in tables, you can choose relational database. However, as the website say, the performance of non relational database is better than relation database. My data can be organized in tables but I don't want to lose performance.
My need is to store huge amount of data and access them as fast as possible. So how can I decide between relational or non relational database.
It's about more than performance. Google can find lots of sources to help you choose, like this one:
I would be surprised if you could measure a performance difference in your app and lay it at the feet of the database. Relational databases are quite performant. I doubt that your requirements are that special.Your code, latency, or other factors are likely to be bigger problems.
I would isolate the database in your code behind an interface and prototype both using real data and use cases. No one can answer here but you; better to do it with data than to guess.