Tencent cloud has two sides in an hour, which is almost as terrible as one side..

today 11:40 Wait until the interview , Start the interview after a brief self introduction

problem

1. Interviewer gives 10 Base to zero 2 Binary title , Online hand tear code
2. The representation of a negative number in a computer , How to convert ？（ Complement code , Counter code, etc ）
3. select and epoll difference ？（ File descriptor limit , Data structure adopted ）
4. select and epoll For the difference between user state and kernel state consumption ？（select Based on user status ,epoll Red black tree is based on kernel state, etc ）
5. Introduce how to judge a socket Can be read ？（ A face of meng , Said to receive the data , received FIN, received SYN etc. , The interviewer asked me SYN Will make socket Readable ？ Muddled ）
6. epoll How to realize multiplexing ？（ from epoll_create, epoll_ctl, epoll_wait The three functions speak of , And detailed description, including red black tree event registration , Add active events to the two-way linked list ）
7. epoll Why use red and black trees and list？（ contrast select, Using red black tree can make the time complexity reach log n, If the linked list is used, the operation of adding and deleting is more convenient , No number limit, etc ）
8. epoll There are two ways to trigger ？（ET,LT, The application scenarios of the two are described in detail ）
9. Hash table and list What's the difference? ？（ combination STL For both implementations ）
10. The red and black trees are STL What are the applications in ？（set, map, The data structure of red black tree is described in detail ）
11. STL How do I implement a hash table ？（ From hash method , To hash conflict resolution , To hash table expansion , And why prime numbers are used ）

project

To put it simply, I made a website , And said it used mysql etc.

1. Look at the testing tools used in your project , How do you test ？（ From memory leak tool valgrind, To tcpdump, tcpcopy, wireshark Speaking of ）
2. If one TCP There's a problem with the connection , How do you rule out ？（ from nginx and apache Use experience to talk about , Check the configuration file , Check the network condition , Check the network card ,DNS, System use, etc ）
3. What tools do you have to check ？（ Memory aspect free, vmstat, process top, ps, The Internet netstat, ip Wait for the order ）
4. Database master-slave replication ？（ Why use master-slave replication , Separation of reading and writing ）
5. How does the master-slave assistant ensure the execution of events ？（ Just to put it briefly mysql Support for events , And atomicity , Isolation and other four characteristics , Again bin-log Support it ）
6. How to include four operations in an event , From the server to the 3 Operations failed , What will happen ？（ To be honest, it's not very clear , But combine redis Support for transactions is vague ）
7. redis and mysql How to understand cache consistency ？（ Give me an example , Why would there be redis Make the middle layer , And why we should change the database first and then the data in the cache ）
8. redis How to locate data ？（ No answer .... Really confused ）
9. Where is your house? ？

summary

None of the interviews took long , Only 1 Hours 10 minute , After the interview, the interviewer said he would evaluate the interview results , Give me an answer as soon as possible .

Wait, wait ~ I hope I can live ~