The interview lasts about 90 minutes, and you need to do a lot of preparation, but you are a little confused except for the concept. After coming back, I classified these topics and sorted out the answers (OBSessive-compulsive me crazy supplement knowledge) into MySQL+Java+Redis+ algorithm + network +Linux and other six categories. Next, I would like to share my experience of the United States ++ some of my study notes.

Note: MySQL+Java+Redis+ network +Linux and other six types of interview answers, learning notes, thinking brain map (XMIND) friends can scan the following TWO-DIMENSIONAL code, assistant will reply to everyone ~

01 MySQL related

1.1 Meituan interview questions

  • What locks does MySQL have?
  • What is ACID
  • Innodb index implementation
  • B + tree
  • The principle of AUTO_INCREMENT
  • What kinds of indexes are there in a database? Why index B+ trees? What is the difference between a composite index and several individual indexes? Large table query optimization for database? Do you understand the MVCC mechanism? What’s wrong with MVCC? How to solve this problem? Mysql slow statement tuning done? Tell me how you did it.

1.2 My MySQL learning notes

(1) MySQL interview

  • Atomicity, consistency, Isolation, durability?
  • Concurrency of transactions? Transaction isolation levels, what problems are caused by each level, which level is MySQL’s default?
  • MySQL storage engine InnoDB, MyISAM, MEMORY
  • MySQL MyISAM and InnoDB two storage engines in, transaction, lock level, their applicable scenarios?
  • The order in which different elements (WHERE, jion, limit, group by, Having, and so on) are executed?
  • What is a temporary table and when does a temporary table drop?
  • MySQL > alter table B+Tree Hash index
  • What type of index does the SQL query determine to create? How to optimize queries?
  • What is the difference between a clustered index and a non-clustered index?
  • What locks (optimistic locks pessimistic locks), select how to add an exclusive lock?
  • Non-relational database and relational database differences, advantages comparison?
  • Database three paradigms, according to a scenario design data table?
  • Read/write separation, master-slave replication, master-slave replication analysis of databases
  • Optimize SQL and indexes with Explain?
  • MySQL > slow query
  • What are inner join, outer join, cross join, Cartesian product, etc.?
  • Mysql > select * from ‘mysql’ where deadlock is determined
  • How to use varchar and char?
  • Mysql High concurrency environment solution?
  • What are the recovery mechanisms for transactions in the event of a database crash (REDO and UNDO logs)?

MySQL interview tips

(2) MySQL Learning Mind map (XMIND)

MySQL learning mind brain map

02 Java related

2.1 Meituan interview questions

  • JVM memory model
  • GC garbage collection algorithm
  • Explain the new generation and the old age
  • What are the basic types of Java? Is String a Java base type? Why is String final?
  • What about the JVM’s threading model? What are these areas for? The Java thread model is distinguished from the JVM thread model

2.2 My JAVA learning Notes

(1) JAVA interview treasure book

JAVA interview guide

(2) JAVA Concurrent System learning Mind Map (XMIND)

JAVA concurrent architecture learns mind brain diagrams

(3) Multi-threaded concurrent Programming learning Mind Map (XMIND)

Multithreaded concurrent programming learning mind brain map

03 Redis related

3.1 Meituan interview questions

  • Does Redis understand? How to use Redis to implement distributed lock?
  • Redis common data structure and the implementation of the underlying data structure
  • How to solve the Redis concurrent competing Key problem
  • How to ensure data consistency between the cache and the database in dual write?

3.2 My Redis study notes

(1) 14 high frequency Redis knowledge points

  • Introduction of redis
  • Why Redis/Why cache (high performance, high concurrency)
  • Why redis and not Map/Guava?
  • The difference between Redis and memcached
  • Redis common data structures and usage scenario analysis (String, Hash, List, Set, Sorted Set)
  • Redis sets the expiration time
  • Redis memory flushing mechanism (MySQL has 2000W data, redis only 20W data, how to ensure that redis data is hot data?)
  • Redis persistence mechanism (how to ensure that redis hangs and then restarts data can be recovered)
  • Redis transactions
  • Redis common exceptions and solutions (cache penetration, cache avalanche, cache warming, cache degradation)
  • Common application scenarios in distributed environment (distributed lock, distributed auto-increment ID)
  • Redis Cluster mode (master-slave mode, Sentinel mode, Cluster mode)
  • How to solve the Redis concurrent competing Key problem
  • How to ensure data consistency between the cache and the database in dual write?

14 High frequency Redis knowledge

(2) Redis Learning Mind Brain Map (XMIND)

Redis learns mind brain maps

04 Thinking/algorithm

4.1 Meituan interview questions

  • GBDT splitting is performed using O(N) complexity
  • Find the longest distance between inversions in an unordered array
  • Given a RAND5 (), implement a uniformly distributed RAND7 () generator
  • At one point, go 5 km north, 10km east, 5 km south and return to the origin. There are a couple of points like that. Prove that.
  • There is an n-gram object, a balance and several weights. The balance has no scale. How many and what weights can be used to weigh the mass of this object? The mass and number of weights are specified by themselves.

4.2 Algorithm brush

  • Programming skills
  • The linear table
  • string
  • The stack and queue
  • The tree
  • The sorting
  • To find the
  • Enumeration of violence
  • Breadth-first search
  • Depth-first search
  • Divide and conquer method
  • Greedy method
  • Dynamic programming
  • figure
  • Detailed implementation problem

Algorithm to brush the topic

05 Related to the OPERATING system and Linux

5.1 Meituan interview questions

  • Cause of deadlock
  • What is the difference between a process and a thread
  • How to implement a thread pool and how to configure it in Java
  • This section describes the common commands in Linux
  • Select, poll, epoll
  • Thread switching, extended to Java blocking ➡️ runs
  • Page replacement algorithm is introduced

5.2 Linux Learning Guide

Linux learning guide

06 Network Related

6.1 Meituan interview questions

  • What is the OSI seven-tier model
  • Network protocols, for example, at which layer
  • TCP UDP difference
  • How does TCP implement reliable connections
  • 2* MSL in Time_Wait
  • What happens if TCP suddenly fails the receiver
  • HTTP status code meaning, 503 504,200
  • GET the POST difference
  • How a URL goes from input to access
  • Talk about TCP three handshakes and four waves

6.2 JAVA Core knowledge collection (JVM, JAVA Collection, Network, JAVA Multi-threaded concurrency, JAVA Fundamentals, Spring Principles, Microservices, Zookeeper, Kafka, RabbitMQ, Hbase, MongoDB, Cassandra, Design mode, load balancing, Databases, consistent hashing, JAVA Algorithms, Data structures, encryption algorithms, distributed caching)

JAVA Core knowledge collation – network

The last

JAVA Architecture interview question + analysis + my JAVA learning books

Important thing again, need to share all the study notes of the friends attention: like + follow, scan the TWO-DIMENSIONAL code, free to receive