show global variables

Com. mysql. jdbc. exceptions. jdbc4.CommunicationsException: callback. Thedriverhasnotreceivedanypacketsfromtheserver. This is a recent error and is a common jdbc link, Com. mysql. jdbc. exceptions. jdbc4.CommunicationsException:

Mysql memory allocation is the top priority of optimization, so you must understand how the memory is allocated mysqlshowglobalvariableslike #39; % buffer % #39 ;; + ------------------------- + ------------ + | Variable_name... mysql memory

Mysql modifies wait_timeout bitsCN.com Mysql modifies wait_timeout Mysql> show global variables like 'Wait _ timeout '; The default value is 8 hours. If a connection of mysql is idle for more than 8 hours, mysql will automatically

What are the Redo log Undo logs in MySQL?In the database system, there are both data files and log files. Logs also contain cached Log buffer and disk file log files in the memory. This document describes the files that store logs. There are two

1. In the MySQL database, the SQL language consists of the following parts. (1) Data Definition Language (DDL ). It is used to execute database tasks and perform create, drop, alter, and other operations on the database and various objects in the

Mysql modifies wait_timeout Mysql> show global variables like 'wait _ timeout ';  The default value is 8 hours for a mysql connection to be idle for more than 8 hours. mysql will automatically disconnect the connection. 1. modify vi/etc/my. cnf

MySQL5.6 how to optimize slow query SQL statements -- Introduction to slow logs Recently, a development team complained that the mysql cluster included in our platform was not good and always reported the "heartbeat Error" of mysql and analyzed the

MySQL experience 6-MySQL language structure-constant, variable bitsCN.com 1. in MySQL database, the SQL language consists of the following parts. (1) Data Definition Language (DDL ). It is used to execute database tasks and perform create, drop,

1. check the MySQL running time. mysqlSHOWGLOBALSTATUSLIKEUPTIME; + --------------- + ------- + | Variable_name | Value | + --------------- + ------- + | Uptime | 12823 | + ---- 1. check the MySQL running time. mysql> SHOW GLOBAL STATUS LIKE

[SQL] MySQL uses mysqlbinlog for incremental backup and recovery details bitsCN.com [SQL] MySQL uses mysqlbinlog for incremental backup and recovery Incremental Backup process (1) configure the My. cnf file (Configure the my. ini file in Windows)

Recently, a development team complained that the mysqlcluster on our platform was not good and always reported mysql heartbeatError. after analyzing the logs they collected, they did not find any network problems between mysqlcluster nodes, however,

Today, an ERROR message "ERROR 2006 (HY000) at line 534: MySQL server has gone away" is prompted when you import a database to a customer's website to migrate a VPS host, generally, this problem occurs when the database is too large and the

MYSQ Binlog three modes and settings method 1.1 row level row mode log records the form of each row of data being modified, then modifies the same data on the slave sideAdvantages:In row level mode, Bin-log can not record the context-sensitive

Variables are divided into user variables and system variables. User variable: User variables are related to database connections. variables declared in this connection will disappear when the connection is disconnected. Variables declared in this

If you have not modified the MySQL configuration, the initial value of wait_timeout is 28800 by default. Wait_timeout has many drawbacks. It is reflected that a large number of sleep processes in MySQL cannot be released in time, dragging down

If you have not modified the MySQL configuration, the initial value of wait_timeout is 28800 by default.Wait_timeout has many drawbacks. It is reflected that a large number of sleep processes in MySQL cannot be released in time, dragging down system

MySQL Semisynchronous Replication In addition to the built-in asynchronous replication mechanism, MySQL5.5 also provides interfaces to support semi-synchronous replication. Disadvantages of asynchronous replication: MySQL replication is asynchronous

Mysql Character Set and mysql Character SetMysql Character Set Character Set Basic Character Set: the character set in the database contains two meanings character set classification: ASCII: Standard American information interchange code; English

Mysql master-slave and master-slave replication configuration demonstration, mysql master-slave Experimental System: CentOS 6.6 _ x86_64 Prerequisites: Prepare the compiling environment in advance, and disable both firewall and selinux. Tutorial

For example, set the MySQL instance parameter wait_timeout to 10 seconds.   1) method 1 for setting global variables (not recommended): Modify the parameter file and restart mysqld. # Vi/etc/My. CNF [Mysqld] Wait_timeout = 10 # Service mysqld