Database Administrator

Install and configure Redis on a Linux Server 1. Download and install redis On a Linux server, run the following command on the command line (the General source code of cd./usr local/src is put here (the installation of source code is recommended ))

MongoDB replica set: concept and featuresConcept of replica set A Replica Set (also called Replica Set) is a master-slave cluster with the automatic fault recovery function. The most obvious difference between the traditional master-slave structure

Detailed description of MySQL query Cache Query cache stores the text returned to the client using the SELECT syntax query. When the same request occurs again, data is retrieved from the query cache instead of being queried again. The query cache is

MySQL explain Execution Plan OptimizationExplain execution plan Introduction to MySQL optimization: First discover the problem (slow query, profile) If indexes are used and no indexes are used, you can quickly find data by using indexes. What is

Understanding of B + tree and index in MySQLOverview Nature: Databases maintain certain data structures and reference (point to) data in some way Index selection principle: the structure of the index should minimize the number of disk I/O

MySQL Optimization TechnologyIntroduction The static page technology can cache dynamic data, but sometimes you still need to request the database. Therefore, database optimization is indispensable.Optimization ideas DESIGN: storage engine, field,

Common commands for viewing ASM disk Information 1.1 obtain disk Group Management Information1.1.1 view the disk pathSQL> selectname, path, group_number from v $ asm_disk_stat; 1.1.2 view disk group informationSQL> selectstate, name, type, total_mb,

MySQL stores logs and uses Loganalyzer for front-end display Why use logs?In the production environment, we may need a complete log system to view the status and operations of the running host service, we can use ELK in a larger network architecture

MySQL buffer query and non-buffer Query Recently I encountered the following error when developing a PHP program: PHP Fatal error: Allowed memory size of 268 435 456 bytes exhausted The error message shows that the maximum allowed memory is

Use shell to generate scripts for integrated data migration in batches For integrated data migration, it is basically the two-in-one, four-in-one, and eight-in-One rhythm of the Overlord, which integrates data from databases that are as relevant to

Install and configure MySQL in UbuntuInstall MySQL in Ubuntu Command: sudo apt-get install mysql-serverMySQL initial configuration and management Start MySQLMysql start: mysqld is the mysql daemon Check whether mysql is started:ps -ef | grep

Understanding of MySQL transaction commit and rollback errors I. Cause Begin or start transaction to START a TRANSACTION Rollback transaction rollbackCommit transaction validation The transaction is interpreted as follows: a transaction is composed

Calculate the value of ken_len In the MySQL query plan This article first introduces the meaning of ken_len In the MySQL query plan, then introduces the calculation method of key_len, and finally uses a forged example, to show how to use key_len to

Install MySQL in Linux source code Today, in Ubuntu and CentOS, MySQL has been installed many times with the source code. Remember to write it down before you forget it. There is no difference in the installation process in Ubuntu and CentOS. 0.

MySQL interactive connection & non-interactive connection Interactive operations: in layman's terms, you open the mysql client on your local machine, that is, the black window, and perform various SQL operations in the black window, of course, it

Sqlplus/as sysdba cannot log on I recently read a question, but it was really strange to see it. It bothered me for a while.The background of the problem is to help developers solve a database problem. After the problem is solved, I want to perform

FORMATA format description of RMAN The following replace variables can be used when the FORMAT parameter is used: % A: The activation ID of the Oracle database is RESETLOG_ID. % C: number of copies of the backup fragment (starting from 1, up to 256 )

Master-slave synchronization configuration of MySQL Databases in Linux Master-slave synchronization configuration of MySQL Databases in Linux 1. Configure the mysql master database #172.30.65.122 Mysql-u root-p # enter the Console Create database

Create and delete a MongoDB DatabaseMongoDB database creation syntax The syntax format for creating a MongoDB database is as follows: use DATABASE_NAME If the database does not exist, create a database. Otherwise, switch to the specified

MongoDB Concept Analysis In mongodb, the basic concepts are documents, collections, and databases. We will introduce them one by one. The following table helps you better understand some Mongo concepts: SQL terms/concepts MongoDB