MySQL

The mysql Database id cannot be deleted because the database has not been involved for a long time, and the SQL statements have forgotten a lot. Recently, this is only because the backend server uses Mysql to store data. In order to make online time

The iptables setting problem after mysql master-slave synchronization is enabled is that the two are performing master-slave mysql synchronization. My mysql Server version is 5.6.10, and mysql5.6 is used for master-slave synchronization, the

Mysql-utilities tool experience I mainly experienced several REPLICATION tools. Let's talk about my environment: MASTER: 192.168.1.20.slave: 192.168.1.132, and 192.168.1.20.all three databases have external users with ALL permissions. The

Mysql common operations add new users/assign permissions/modify tables/index bin> mysql-u root mysql> grant permission 1, permission 2 ,... Permission n on database name. Table name to user name @ user address identified by 'Connection password';

Centos 5.9 install mysql 5.5.31 install mysql in linux, there will be a variety of dependencies, install mysql in centos with various dependencies [root @ localhost] # tar xzvf cmake-2.8.4.tar.gz [root @ localhost src] # cd cmake-2.8.4 [root @

Slow query caused by incorrect use of MySQL prefix index the front-end time is related to a DB project. alanc reports that there is a query. Using indexes is much slower than not using indexes, which is a little ruined. So I followed up and used

MYSQL: temporary table problems, do not support self-join TEMPORARY table ProblemsThe following list indicates limitations on the use of TEMPORARY tables: a temporary table can only be of type MEMORY, ISAM, MyISAM, MERGE, or InnoDB. temporary tables

After mysql inserts data, it returns an auto-incremental ID. The difference between mysql and oracle is that oracle supports sequence id, and mysql itself has a column that can be used as an auto-increment field, after inserting a piece of data, how

[MySQL] InnoDB features-two writes today we will introduce the second feature of the InnoDB Storage engine-two writes (doublewrite). If the insert buffer is used to improve the write performance, therefore, the two writes sacrifice a little bit of

Mysql index -- (mysql 2) index type: basic index primary key foreign keyunique indexnon-unique professional index: -- B-tree balanced number index, different from binary tree. the height of a binary tree may be very high. The balance tree may not be

Enable mysql slow query log and run the mysqldumpslow command to check which SQL statement query is slow, that is, slow query slowlog. Now we will introduce how to enable this function. Add the following code under [mysqld]: long_query_time =

Analysis of the lock Table Mechanism During mysql query update in order to better optimize mysql in high concurrency, it is necessary to understand the lock Table Mechanism During mysql query update. I. Overview MySQL has three lock levels:

Basic functions of MySQL Stored Procedure (1 ). string CHARSET (str) // returns the string Character Set CONCAT (string2 [,...]) // connection string INSTR (string, substring) // returns the position of the first occurrence of the substring in the

After mysql is reinstalled, garbled code appears. Solution: view the current connection system parameters: SHOW VARIABLES LIKE '%char%';mysql> show variables like 'char%';+--------------------------+----------------| Variable_name | Value+

InnoDB's Redo Undo Log this article introduces the MySQL database InnoDB Storage engine Redo Log roaming-Undo Log is to achieve the atomicity of transactions, in the MySQL database InnoDB Storage engine, the Undo Log is also used to implement

Set up mysql semi-synchronous replication (semi_sync_replication) and use google to develop a patch for mysql based on semi-synchronous, application and mysql5.0. Mysql is installed with this patch and used in mysql 5.5. What is the concept of

In MySQL, inserting a record is very simple, but in some special applications, before inserting a record, you need to check whether the record already exists. The insert operation is performed only when the record does not exist, this article

The wrong answer is also accepted, misleading. Char cannot exceed 255 charactersVarchar can contain a maximum of 65535 bytes. Therefore, the number of characters stored in different character sets is different)Text cannot exceed 65535 characters 1)

Alter table allows you to modify the structure of an existing TABLE. For example, you can add or delete columns, create or delete indexes, change existing column types, or rename columns or tables. You can also change the comment and type of the

In my testing environment, data is basically synchronized in an instant and I hope it will be helpful to you. Redhat 9.0Mysql3.23.57 Mysql Data Synchronization backup Server A: master server 192.168.1.2Server B: 192.168.1.3 slave server slave Server