Database Administrator

Implement master-slave synchronization between two MySQL Databases I. OverviewMySQL versions later than 3.23.15 provide the database replication function, which enables the synchronization, master-slave mode, and mutual backup of two databases.II.

Using Redis as a time series database: Reasons and Methods Since the emergence of Redis, it has been used in the storage and analysis of time series data to a certain extent. Redis was initially implemented as a buffer for logging. With the

MySQL query plan key_len all know 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 view the number of

MySQL has more slave database logs than the master database When chatting in the Group, a group member said that the master database of the MySQL production database is down, but the data of the master and slave databases is consistent, but the

How can I test your MongoDB application upgrade? You have selected MongoDB as your application database. You may already have a large amount of production data in your database. Now you need to make a major version change to your application. How do

In CentOS Linux, MySQL databases are automatically backed up every day. In CentOS Linux, MySQL databases are automatically backed up every day. 1. Create the following three folders on the server: mkdir/bak, mkdir/bak/bakmysql, mkdir/bak/bakmysqlold.

Upgrade to MySQL 5.7 to solve the partition problem. Preface Some friends often ask, How is MySQL partition? Can I use it? Are there many bugs? I don't know why MySQL partitions have such an impression on the general public. However, in the

Enumeration of common MyCAT sharding rules MyCAT supports multiple sharding rules. In the following example, partition enumeration is used. In applicable scenarios, the number of column values is fixed, such as province and month. Here, three values

MyCAT Log Analysis MyCAT logs cannot be obtained for running information about MyCAT. For example, if MyCAT adopts read/write splitting, how does MyCAT execute a query statement, and which node each shard is distributed. The default value is the

Practices for restoring data using MySQL binlog A few days ago, I worked overtime until. On the way back, a friend called and said that the development and maintenance staff of their company were updating the online system versions, accidentally

SQL Server automatic backup script SQL Server backup script: Third-party backup, and differential backup at other times. declare  @device  varchar (30); declare  @filename  varchar (50); declare  @datetime  varchar (50);

MySQL import of large data volumes First: in fact, the best way is to directly use: Mysqldump-u username-p Password Database Name In Linux, we tested an imported data of over 10 thousand rows, totaling 121 MB. In Linux, the import is successful

Solve the Problem of invalid Oracle environment variables in Linux When you maintain the Oracle database in Linux today, view the listener status and execute # Lsnrctl status Error:-bash: lsnrctl: command not found. This is not the case in the

Restoration After Oracle data files are physically deleted This is the case for system management. It is inevitable that files will be deleted by mistake. How can we restore an Oracle data file one day? (The database is OPEN and is not closed)

Install Oracle 11G R2 on CentOS 5.10 Operating System: CentOS 5.10 64-bit Database: Oracle 11G R2 (version 11.02) When installing the operating system, note that the swap partition size cannot be less than 2G 1. synchronize clock and

Basic MySQL Tutorial: About varchar (N) PrefaceWhat does varchar (N) N mean and how many Chinese characters can it store? This is a common question. Today I was asked by another developer to write an article about this question. 2. Theoretical

Split Oracle data rows into multiple rows In work and study, we often encounter a situation where one row is divided into multiple rows of data. Here, we will make a comparison. Single Row splitting If the table has only one row of data, you can

Redis master-slave cluster construction and disaster recovery deployment (sentinel) Redis has also been used for a while. Record the cluster construction and configuration details for later use.Outline Install Redis Overall Architecture Redis

SQLite performance optimization instance sharing, sqlite performance optimization instance The first cache database to be found in iOS development was SQLite, which was also used as the backbone in the future. In the past, SQLite was not used to

Difference between Having and Where in SQL, sqlhavingwhere Description Where Select before grouping Having Having can select an aggregation function only after grouping.Eg: // Select count (*) from awhere a. a1> 0 group by a2; // However,