How to design a high concurrency system

Suppose you work in a well-known e-commerce company too high concurrent system , Hundreds of millions of users , Billions of traffic a day , There are tens of thousands of concurrent traffic in the peak period , Even a hundred thousand . Then people will ask about your system architecture , What architecture of your system ？ How to deploy ？ How many machines are deployed ？ How to use cache ？MQ How to use ？ How to use the database ？ It's about digging deep into how you can handle high concurrency .

Because people who do too much concurrent work must know , System architecture that is out of business is all on paper , When the complex business scenario is high concurrency , The system architecture must not be so simple , Use one redis, use mq You can get ？ Of course not. , After the real system architecture is matched with the business , It will be simpler than this so-called “ High concurrency architecture ” It's a lot more complicated .

In fact, the so-called high concurrency , If you want to understand the problem , In fact, we have to start from the root of high concurrency , Why there is high concurrency ？ Why high concurrency is so awesome ？

What I said is a little more simple , It's simple , Because at the beginning, the system was connected to the database , But you need to know that the database is supported to two or three thousand per second , It's almost over . That's why I said , Many companies , At the beginning , Technical comparison low, As a result, the business is developing too fast , Sometimes the system will hang up if it can't bear the pressure .

Of course it will , Why don't you hang up ？ If your database is instantaneously loaded per second 5000/8000, Even tens of thousands of concurrent , It's bound to go down , Because, for example mysql I can't bear such a high concurrency at all .

So why is the high concurrence of Niubi ？ It's because more and more people are using the Internet , quite a lot app、 Website 、 The system hosts high concurrent requests , Maybe thousands of concurrent per second in peak period , It's normal . If it's a double eleven or something , It's possible to have hundreds of thousands of concurrent per second .

So high concurrency , Plus the business that was so complicated ÿ