I am having trouble in terms of handling huge databases. I have multiple clients like 100-300 (clients are basically servers with i.e windows sql). Each client may have 38 thousand rows/listing of data, each row has 10-12 fields. I cannot afford to have json files of each client and than handle them on main server, because of memory issue. What if i have http server written in c or c# installed on clients and they return 250 rows in each response to the main server. How the factors like speed, memory or other issues can effect us ?

What exactly I am asking for ?

In short words if a server writter in c-sharp sends 250 rows per request. What factors can effect the performance of server ? for example. Speed, processing, Operating system, Implementation of algorithm of server ? How these factors can really effect the performance on large scale?