Programmer Think

I thought it might be a log problem, but there is no evidence to support it. The trace command can monitor the time consumption of each step, and can cooperate with the conditional expression to print a detailed log when the time consumption exceeds xx ms. Find a machine, enter a command, and then wait. When rt spikes appear again, the time-c ...

1. Concept of database DB: database: a "warehouse" for storing data. It holds a series of organized data;DBMS: Database Management System. Database is a container created and operated by DBMS;SQL: Structure Query Language: a language specially used to communicate with the database;Relationship diagram of the three: 2. Common ...

Joint query of Mysql union of joint query union can merge tables queried by more than two select statements and eliminate duplicate rows in the table. The select statement needs to have the same number of columns with the same data type. 1. Query the ID and province name of each province in China select ProID,ProName from T_Province 2. I ...

mysql application: 1.client: client program, which connects to the server 2.SQLyog is easy to use and can be executed directly from multiple command lines. 3. Send e-mail: the default port is net25. The default port of the database is 3306. This port is unified according to the port of the server 4.server side: on linux. show databases; Displa ...

<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-hystrix</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nac ...

NPM ======= 1, Introduction to npm The full name of NPM is Node Package Manager JS package management tool is the world's largest module ecosystem, in which all modules are open source and free; It's also a node JS package management tool, which is equivalent to Maven on the front end. 1. Installation location of NPM tools Through npm, w ...

Author: Ke Yuchang consultant Software EngineerCurrently engaged in container R & D of RadonDB MySQL, graduated from Huazhong University of science and technology, and has many years of experience in database kernel development.Mastering the reading and debugging ability of MySQL kernel source code is not only the daily work of database R & ...

preface The database needs to be started during backup and closed during recovery 1, What is Xtrabackup? MySQL cold standby, mysqldump and MySQL hot copy cannot realize incremental backup of the database. In the actual production environment, incremental backup is very practical. If the data is greater than 50G or 100G and the stora ...

Objectives of this unit 1, Why learn database 2, Related concepts of database DBMS,DB,SQL 3, Characteristics of database storage data 4, Initial MySQL MySQL Product introduction MySQL Product installation ★ MySQL Start and stop of services ★ MySQL Login and logout of services ★ MySQL Common ...

Performance tuning cases time2021-09-02environmentcentos7. 6. JMeter, redis, mysql, Java applications 1, jmeter's command line uses give an example: # Run in command line mode and execute test JMX test script, and save the test results to result In JTL jmeter -n -t test.jmx -l result.jtl # Specify IP distributed operation jm ...