MySQL

Sharding has two advantages: Static and Dynamic sharding and static sharding. They are simple, low development costs, and low maintenance costs.Common static sharding methods include Hash Functions and modulo operations, but this exposes a

Principle: Hard link BasicsWhen multiple files point to the same inode, inode connections n> 1, deleting any file is extremely fast.This is because only the pointer to inode is deleted. When n = 1, it is different. At this time, all data

(I) Environment: OS: RHEL-5.8Server: MySQL 5.5Engine: InnoDB (Ii) Problem: Without any operation, the disk I/O load is almost full, and the disk load is still running for 3 or 4 hours. Iotop partial output: Total disk read: 32.55

Sometimes you need to modify the null field value of the returned column when querying the database's left and right connections, for example, return 1 or 0. At this time, the coalese (field, 0) function will be used. This function will change the

After installing MySQL, you will receive the following prompt: [Root @ localhost desktop] # rpm-IVH MySQL-server-5.5.28-1.rhel5.i386.rpmPreparing... ######################################## ### [100%]1: mysql-server #################################

Question: How many steps can an elephant be taken to the refrigerator? Answer:: Open the refrigerator, put it in the elephant, and close the refrigerator. The three-step strategy, haha, and secure configuration replication are also the same. (I)

MySQL cold backup, also called offline backup Is the simplest: ● Simple backup: you only need to copy the relevant files. ● Easy recovery: you only need to store the copied files in the same directory. It is also the safest: ● The optimal method

RealWar environment Introduction: Server Name IP System MySQL Odd.example.com 192.168.1.116 Rhel-5.8 5.5.16 Even.example.com 192.168.1.115 Rhel-5.8 5.5.16 Assume that the database to be

(I) source code compilation ① Install cmake # wget http://www.cmake.org/files/v2.8/cmake-2.8.5.tar.gz # tar -zxv -f cmake-2.8.5.tar.gz -C /usr/local/src # cd /usr/local/src/cmake-2.8.5 # ./bootstrap # make # make

(I) actual environment Server Name · IP OS MySQL Odd.example.com 192.168.1.116 RHEL-5.8 5.5.16 Even.example.com 192.168.1.115 RHEL-5.8 5.5.16 (Ii) advantages and disadvantages of the

Mysql> select version () \ G; * *************************** 1. row *************************** Version (): 5.5.16-Log 1 row in SET (0.00 Sec) [MySQL @ Xilinx ~] $ Mysqld_safe & [1] 3036 [MySQL @ Xilinx ~] $130506 19:16:34 mysqld_safe logging to

(I) authentication and authorization Certification: Who am I? Authorization: what I can do? Authentication is actually a process of verifying creden, And the creden required for entering MySQL include host, username, and password. There are two

(I) Error Log ① Parameters Log_error: Specify the log location and name ② Function (1) Error/alarm information (2) optimization help (Ii) Slow query log ① Parameters Log_slow_queries: Specify the log location and name Long_query_time: SQL

Although this article is intended to understand, but it can be understood a little. After all, Zhuge Kong Ming is Only character-based values have the so-called Character Set Concept. Some character sets may require more CPU, more memory and disk

(1) udev Basics Udev can manage files stored in the/dev directory. Files are generated only after the device is connected, and are automatically deleted after the device is pulled out. It also allows you to add rules to modify the default name and

In essence, a view is only an SQL statement, but MySQL does not store the SQL statement. Instead, we save the view definition in the form of a file like a table, and use. frm to exist. The SQL statement displayed with show create view is unfriendly.

(I) Insert large data volume (1) Replace a single row with multi-row insert: insert into T values (),(),(),... (2) load data infile... into table t (3) Write a temporary table and insert... select (4) cancel the index and constraints, and

1. Create an account dedicated to replication First, the replication operation involves two important permissions, which are described here:The replication client privilege enables the use of show Master Status and show slave status.Replication

Documentation for mysqldump: http://dev.mysql.com/doc/refman/5.1/zh/client-side-scripts.html#mysqldump MysqldumpIt is most commonly used to back up an entire database: shell> mysqldump db_name >backup-file.sql You can read the dump file back to the

1. Install and uninstall MySQL under centos5   (1) run the following command as the root user:   Yum install MySQL   Yum install mysql-Server   Yum install mysql-devel   Yum install mysql-Client   Chgrp-r MySQL/var/lib/MySQL   Chmod-r