MySQL

The beginner in the MySQL initialization step must be familiar with the problem that PHP cannot connect to the database just now when using MySQL. Now, let's take a look at the work to be done, on the premise that you have added the mysql working

The mysql log command has the following types of logs:-log-err query log:-log slow query log:-log-slow-queries Update log: -log-update BINARY log:-log-bin in the mysql installation directory, open my. ini, add the above parameters to the end, save

Use of MYSQL Foreign Key -- modify (ADD) Foreign Key method, Foreign Key names cannot have repeated 1. caseNumber in case_detail created in wms today cannot be associated with case_head. An error is prompted several times after the result is created,

Mysql simulation queue Java code -- initialization data drop table if exists t_msg_queues; create table t_msg_queues (msg_id bigint unsigned not null AUTO_INCREMENT, msg_content VARCHAR (255) not null, owner_thread_id int not null default-1, primary

Mysql table sharding guidelines when using Mysql in large quantities and with high data access, to improve performance, table sharding is required. The following section describes the mysql table sharding standards and will continue to supplement

A bad SQL statement colleague sent an SQL statement, saying that this SQL statement occupies a large amount of server disk space during execution, which is about 10 Gb, and the efficiency is ultra-slow SELECT MIN (order_id ), MAX (order_id) FROM

High-performance MySQL Reading Notes: Find out who holds the lock problem Background: when using MySQL, if the traffic volume is large, there may be a large number of Locked processes, however, it is not easy to identify which SQL is causing the

In MyISAM, key_buffer_size settings Key_read_requests and Key_reads are two counters. Their meanings are as follows: Key_read_requests: the number of requests that read the index from the cache. Key_reads: the number of requests that read the index

MySQL running STATUS query method: run show status directly in the command line to log on to MySQL and run show status. query statements, such as show variables in the same statement. show status is used to view the running STATUS of MySQL, it is

[MySQL] the InnoDB file introduces a notable feature of MySQL: Its pluggable storage engine. Therefore, MySQL files are divided into two types: files related to the MySQL database itself, one is files related to storage engines. This document

[MySQL] Log File overview the log files described here are all files of the MySQL database and have nothing to do with the specific storage engine. The error log of MySQL is similar to alert. log of Oracle. It ends with. err by default. When DBA

Some common O & M records of linux mysql // stop mysql # service mysqld stop // start mysql in safe mode, skip permission check # mysqld_safe -- user = mysql -- skip-grant-tables & // log on to mysql console mysql // modify all root passwords mysql>

Mysql dual-host exception and solution today, Mysql dual-host encountered two problems. Sort out the solution from the Internet and record it: run the following command to view the exception information: SQL code mysql> show slave status \ G; for

The MySQL database table garbled solves the issue of specifying the encoding when creating a mysql database. Many developers use the default encoding, but from my experience, coding databases can avoid garbled characters caused by import and export.

In MySQL, the given time is used to Share a function written yesterday in the nth week of the month. The purpose is to find that the given time is the nth week of the month. [SQL] DELIMITER $ USE't _ girl '$ DROP FUNCTION IF exists' weekofmonth' $

The three locking mechanisms of MySQL database locking mechanism is a rule designed by the database to ensure data consistency and enable the access of various shared resources in an orderly manner during concurrent access. MySQL storage engines use

The mysql backup script writes a mysql backup file today, mainly using the mysqldump tool. The requirement is to back up some databases at three o'clock every day and keep the backups for two days. Simple requirement: The following script #!

MySQL authorization (allowing slave server users to log on to the master server) 1. view the user authorization table select user,host,password from mysql.user;  2. Set a password for the user update mysql.user set password=PASSWORD('root') where

To modify the character set, use the mysql command. Mysql> SET character_set_client = utf8; mysql> SET character_set_connection = utf8; Use mysql> show variables like 'character % '; view, we found that the database encoding has been changed to utf8

The Binary logs of MySQL is cleared and disabled. Recently, MySQL has been flushed. Binary Log eats more than 800 MiB of hard disk space, which interferes with the normal operation of the system. There are many solutions, including directly deleting