Preparing for gold, three silver and four performance optimization interview will ask you ready? (Java performance optimization Daquan)

After so long wait, years after competing applicants should not small, and there were many graduating students or work experience in two or three years of starting a new job.
In fact, a lot to me after 93 to 95 after the younger junior partner, as we ridicule it, in the back-end Java development inside the circle, entering the newcomers are basically CRUD, intensive business oriented.

Many work two or three colleagues told me that with a little tuning. Just work, I did not actually realize the importance of this thing, but then I know how naive I was thinking.

Once, our system development department came a big God, why call him the god? Because he came to the company's one-year period only do one thing, is to cut in half the number of servers, the performance index of the system, but also improves.

I have a friend in a small factory told me that they never go through the company's system performance tuning, after the completion of functional testing on the line, the line has not been any performance problems, why do performance tuning it ?

At that time I will answer him one, if your company does is 12306, do not do it on-line system performance optimization, try what would happen.

Now suppose your system to do an event, product manager tells you expect hundreds of thousands of user visits, ask the system can withstand. If you do not know their own situation the performance of the system, only timidly answered the boss, should be no problem.

All system after completion of the development, more or less, there will be a performance problem, we have to do is to find ways to expose the problem, for example, stress testing, simulation of possible operating scenarios, etc., and then to solve these problems by tuning .

We can also look at the 2019 Baidu, Jingdong, Tencent, Alibaba and other major plant face questions about performance tuning, look at their place of value for performance tuning.

Mysql index data structure and performance optimization

1. SQL query to determine which type of index creation, how to optimize queries?
2. MySQL B + Tree index difference between the index and Hash?
3. What is concurrent transactions?
4. Talk about transaction isolation levels, each level can cause a problem, MySQL default is what level?
5. What coverage index and the clustered index in the end is?
6. What Mysql optimization principles leftmost prefix?
7. Mysql talk Index Tuning specification?
8. Talk about MySQL high concurrency environmental solutions?

The underlying principles of the Java Virtual Machine and Performance Optimization

1. Memory model and a partition, you need to detail what to put in each area?
2. The parent class loader delegate what model?
3. JVM garbage collection algorithms and collector What?
4. How to determine whether an object is alive?
5. GC collector What?
6. What are the characteristics CMS collector and the collector is G1?
7. JVM memory which divided into several zones, each zone is what role?
8. How to optimize the performance of highly concurrent systems based G1 garbage collector?

BIO, NIO, AIO, Netty and Redis threading model

1. BIO, NIO, AIO's the difference?
2. What is blocking and non-blocking IO IO?
3. What is synchronous and asynchronous IO IO?
4. There are several IO model? What are they?
5. What Reactor design and Proactor IO mode?
6. NIO underlying select, poll and epoll realize the difference?
7. Java NIO few core component of what part? What role are?
8. Redis, Netty, Tomcat NIO threading model and what is the connection?

Article, it is difficult to finish.

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