GTID就是全局事务ID(global transaction identifier ),最初由google实现,官方MySQL在5.6才加入该功能。GTID实际上是由UUID+TID
什么是GTID?
GTID就是全局事务ID(global transaction identifier ),最初由google实现,官方MySQL在5.6才加入该功能。GTID实际上是由UUID+TID组成的。其中UUID是一个MySQL实例的唯一标识。TID代表了该实例上已经提交的事务数量,并且随着事务提交单调递增。
什么是多源复制?
多源复制意味着一个服务器能从多个从服务器上复制。这是MariaDB 10.0的一个新特性。
实验系统:CentOS 6.6_x86_64
实验前提:防火墙和selinux都关闭
实验说明:本实验共有3台主机,IP分配如拓扑
实验软件:mariadb-10.0.20
实验拓扑:
使用XtraBackup备份恢复MariaDB数据库
在 CentOS/RHEL/Scientific Linux 6 下安装 LAMP (Apache with MariaDB and PHP)
MariaDB10.0实例部署和多源复制配置
MariaDB Proxy读写分离的实现
Linux下编译安装配置MariaDB数据库的方法
CentOS系统使用yum安装MariaDB数据库
安装MariaDB与MySQL并存
Ubuntu 上如何将 MySQL 5.5 数据库迁移到 MariaDB 10
[翻译]Ubuntu 14.04 (Trusty) Server 安装 MariaDB
一、准备工作
1.修改三台主机的名字,对应如下:
2.三台主机配置相同的hosts文件为如下内容:
3.安装mariadb:
tar xf mariadb-10.0.20-linux-x86_64.tar.gz -C /usr/local/
cd /usr/local/
ln -sv mariadb-10.0.20-linux-x86_64 mysql
mkdir -pv /mydata/data
useradd -r mysql
chown -R mysql.mysql /mydata/data/
cd mysql/
chown -R root.mysql .
scripts/mysql_install_db --user=mysql --datadir=/mydata/data/
cp support-files/my-large.cnf /etc/my.cnf
cp support-files/mysql.server /etc/init.d/mysqld
chkconfig --add mysqld
chkconfig mysqld on
4.修改配置文件:
vim /etc/my.cnf
--------------------------------->
[mysqld]
datadir = /mydata/data
5.创建虚拟机镜像(可选):
为了试验不受干扰,做完GTID试验我会将三台主机恢复至初始状态。
二、GTID复制
1.将mysql1配置为master:
[mysqld]
server-id = 1
binlog-format=ROW
log-bin=/mydata/data/master-bin
log-slave-updates=true
master-info-repository=TABLE
relay-log-info-repository=TABLE
sync-master-info=1
slave-parallel-threads=2
binlog-checksum=CRC32
master-verify-checksum=1
slave-sql-verify-checksum=1
binlog-rows-query-log_events=1
report-host=mysql1
2.将mysql2配置为slave:
[mysqld]
server-id = 2
binlog-format=ROW
log-bin=/mydata/data/mysql-bin
log-slave-updates=true
master-info-repository=TABLE
relay-log-info-repository=TABLE
sync-master-info=1
slave-parallel-threads=2
binlog-checksum=CRC32
master-verify-checksum=1
slave-sql-verify-checksum=1
binlog-rows-query-log_events=1
report-host=mysql2
3.将mysql3配置为slave:
[mysqld]
server-id = 3
binlog-format=ROW
log-bin=/mydata/data/mysql-bin
log-slave-updates=true
master-info-repository=TABLE
relay-log-info-repository=TABLE
sync-master-info=1
slave-parallel-threads=2
binlog-checksum=CRC32
master-verify-checksum=1
slave-sql-verify-checksum=1
binlog-rows-query-log_events=1
report-host=mysql3
4.在master节点创建复制用户:
service mysqld start
/usr/local/mysql/bin/mysql
-------------------------------------------->
GRANT REPLICATION SLAVE,REPLICATION CLIENT ON *.* TO 'jason'@'192.168.19.%' IDENTIFIED BY '123456';
FLUSH PRIVILEGES;
5.在两台slave节点同时操作:
service mysqld start
/usr/local/mysql/bin/mysql
------------------------------------------->
CHANGE MASTER TO MASTER_HOST='mysql1',MASTER_USER='jason',MASTER_PASSWORD='123456',MASTER_USE_GTID=slave_pos;
START SLAVE;
6.在slave节点查看状态:
SHOW SLAVE STATUS\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: mysql1
Master_User: jason
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: master-bin.000007
Read_Master_Log_Pos: 321
Relay_Log_File: mysql2-relay-bin.000002
Relay_Log_Pos: 613
Relay_Master_Log_File: master-bin.000007
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
...
Using_Gtid: Slave_Pos

InnoDB uses redologs and undologs to ensure data consistency and reliability. 1.redologs record data page modification to ensure crash recovery and transaction persistence. 2.undologs records the original data value and supports transaction rollback and MVCC.

Key metrics for EXPLAIN commands include type, key, rows, and Extra. 1) The type reflects the access type of the query. The higher the value, the higher the efficiency, such as const is better than ALL. 2) The key displays the index used, and NULL indicates no index. 3) rows estimates the number of scanned rows, affecting query performance. 4) Extra provides additional information, such as Usingfilesort prompts that it needs to be optimized.

Usingtemporary indicates that the need to create temporary tables in MySQL queries, which are commonly found in ORDERBY using DISTINCT, GROUPBY, or non-indexed columns. You can avoid the occurrence of indexes and rewrite queries and improve query performance. Specifically, when Usingtemporary appears in EXPLAIN output, it means that MySQL needs to create temporary tables to handle queries. This usually occurs when: 1) deduplication or grouping when using DISTINCT or GROUPBY; 2) sort when ORDERBY contains non-index columns; 3) use complex subquery or join operations. Optimization methods include: 1) ORDERBY and GROUPB

MySQL/InnoDB supports four transaction isolation levels: ReadUncommitted, ReadCommitted, RepeatableRead and Serializable. 1.ReadUncommitted allows reading of uncommitted data, which may cause dirty reading. 2. ReadCommitted avoids dirty reading, but non-repeatable reading may occur. 3.RepeatableRead is the default level, avoiding dirty reading and non-repeatable reading, but phantom reading may occur. 4. Serializable avoids all concurrency problems but reduces concurrency. Choosing the appropriate isolation level requires balancing data consistency and performance requirements.

MySQL is suitable for web applications and content management systems and is popular for its open source, high performance and ease of use. 1) Compared with PostgreSQL, MySQL performs better in simple queries and high concurrent read operations. 2) Compared with Oracle, MySQL is more popular among small and medium-sized enterprises because of its open source and low cost. 3) Compared with Microsoft SQL Server, MySQL is more suitable for cross-platform applications. 4) Unlike MongoDB, MySQL is more suitable for structured data and transaction processing.

MySQL index cardinality has a significant impact on query performance: 1. High cardinality index can more effectively narrow the data range and improve query efficiency; 2. Low cardinality index may lead to full table scanning and reduce query performance; 3. In joint index, high cardinality sequences should be placed in front to optimize query.

The MySQL learning path includes basic knowledge, core concepts, usage examples, and optimization techniques. 1) Understand basic concepts such as tables, rows, columns, and SQL queries. 2) Learn the definition, working principles and advantages of MySQL. 3) Master basic CRUD operations and advanced usage, such as indexes and stored procedures. 4) Familiar with common error debugging and performance optimization suggestions, such as rational use of indexes and optimization queries. Through these steps, you will have a full grasp of the use and optimization of MySQL.

MySQL's real-world applications include basic database design and complex query optimization. 1) Basic usage: used to store and manage user data, such as inserting, querying, updating and deleting user information. 2) Advanced usage: Handle complex business logic, such as order and inventory management of e-commerce platforms. 3) Performance optimization: Improve performance by rationally using indexes, partition tables and query caches.


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