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MySQL学习笔记（Day006：存储引擎二/多实例安装）

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MySQL学习笔记（Day006：存储引擎二/多实例安装）

一. MyISAM存储引擎(下)

1. MyISAM还在使用的原因

  • 历史原因，需要逐步替换
  • 部分如User，DB等系统表(MyISAM引擎)，可以直接拷贝，比较方便
  • 性能好，或者存储小不是MyISAM的优点，也不是存在的原因

2. MyISAM文件组成

  • frm 表结构文件
  • MYI 索引文件
  • MYD 数据文件
    • 数据文件是堆表数据结构，堆是无序数据的集合
    • MYI中的叶子节点，指向MYD中的数据页
    • 当数据移动到页外时，需要修改对应指针

3. myisamchk

myisamchk通过扫描MYD文件来重建MYI文件；如果MYD文件中某条记录有问题，将跳过该记录

二. Memory存储引擎

1. Memory介绍

  • 全内存存储的引擎
  • 数据库重启后数据丢失
  • 支持哈希索引
  • 不支持事物

####2. Memory特性

  • 千万不要用Memory存储引擎去做缓存(Cache), 性能上不及Redis和Memcahced
  • Memory不能禁用，当涉及内部排序操作的临时表时，使用该存储引擎
    • max_heap_table_size决定使用内存的大小，默认时16M
      • 无论该表使用的什么引擎，只要使用到临时表，或者指定Memory，都受参数影响
    • 当上面设置的内存放不下数据时，(>=5.6)转为MyISAM,(>=5.7)转为InnoDB
      • 注意磁盘上临时路径空间的大小(tmpdir)
    • 内存使用为会话(SESSION)级别，当心内核OOM
  • 支持哈希索引，且仅支持等值查询
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mysql> show global status like "%tmp%tables";
+-------------------------+-------+
| Variable_name           | Value |
+-------------------------+-------+
| Created_tmp_disk_tables | 0     |   -- 内存放不下，转成磁盘存储的数量,如果过大，考虑增大内存参数
| Created_tmp_tables      | 4     |   -- 创建临时表的数量
+-------------------------+-------+
2 rows in set (0.00 sec)

mysql> show variables like 'tmpdir';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| tmpdir        | /tmp  |  -- memory转成磁盘存储的路径
+---------------+-------+
1 row in set (0.00 sec)

mysql> show create table User\G
*************************** 1. row ***************************
Table: User
Create Table: CREATE TABLE `User` (
`id` int(11) NOT NULL,
`name` varchar(128) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `name` (`name`) USING HASH  -- 对这个字段使用USING HASH,创建hash索引
) ENGINE=MEMORY DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

3. Memory的物理特性

  • 内存不会一次性分配最大空间，而是随着使用逐步增到到最大值
  • 通过链表管理空闲空间
  • 使用固定长度存储数据
  • 不支持BLOB和TEXT类型
  • 可以创建自增主键

三. CSV存储引擎

1. CSV介绍

  • CSV - Comma-Separated Values，使用逗号分隔
  • 不支持特殊字符
  • CSV是一种标准文件格式
  • 文件以纯文本形式存储表格数据
  • 使用广泛

2. CSV文件组成

  • frm 表结构
  • CSV 数据文件
  • CSM 元数据信息

2. CSV特性

  • MySQL CSV存储引擎运行时，即创建CSV文件
  • 通过MySQL标准接口来查看和修改CSV文件
  • 无需将CSV文件导入到数据库，只需创建相同字段的表结构，拷贝CSV文件即可
  • CSV存储引擎表每个字段必须是NOT NULL属性

四.Federated存储引擎

1. Federated介绍

  • 允许本地访问远程MySQL数据库中表的数据
  • 本地不存储任何数据文件
  • 类似Oracle中的DBLink
  • Federated存储引擎默认不开启, 需要在my.cnf的[mysqld]标签下添加 federated
  • MySQL的Federated不支持异构数据库访问，MariaDB中的FederatedX支持

2. Federated 语法

scheme://user_name[:password]@host_name[:port_num]/db_name/tbl_name

CONNECTION='mysql://username:password@hostname:port/database/tablename'

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--
-- 例子
--
CREATE TABLE `T1` (
`A` VARCHAR(100),
UNIQUE KEY (`A` (30))
) ENGINE=FEDERATED
CONNECTION='MYSQL://david:123@127.0.0.1:3306/TEST/T1';

五. 多实例安装

1. 多实例介绍

  • 一台服务器上安装多个MySQL数据库实例
  • 可以充分利用服务器的硬件资源
  • 通过mysqld_multi进行管理

2. 安装要求

  • MySQL实例1 - mysql1

    • port = 3306
    • datadir = /data1
    • socket = /tmp/mysql.sock1

  • MySQL实例2 - mysql2

    • port = 3307
    • datadir = /data2
    • socket = /tmp/mysql.sock2

  • MySQL实例3 - mysql3

    • port = 3308
    • datadir = /data3
    • socket = /tmp/mysql.sock3

  • MySQL实例4 - mysql4

    • port = 3309
    • datadir = /data4
    • socket = /tmp/mysql.sock4

该三个参数必须定制，且必须不同 (port / datadir / socket)
server-id和多数据库实例没有关系，和数据库复制有关系。

3. 安装操作

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#
# 多实例配置文件，可以mysqld_multi --example 查看例子
#
[root@MyServer /]> cat /etc/my.cnf 
#[client]           # 这个标签如果配置了用户和密码，
                    # 并且[mysqld_multi]下没有配置用户名密码，
                    # 则mysqld_multi stop时, 会使用这个密码
                    # 如果没有精确的匹配，则匹配[client]标签
#user = root        
#password = 123
#-------------
[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
user = multi_admin
pass = 123  # 官方文档中写的password，但是存在bug，需要改成pass(v5.7.9)
            # 写成password，start时正常，stop时，报如下错误
            # Access denied for user 'multi_admin'@'localhost' (using password: YES)
log = /var/log/mysqld_multi.log


[mysqld1]  # mysqld后面的数字为GNR, 是该实例的标识
           # mysqld_multi  start 1,  mysqld_multi start 2-4
server-id = 11
socket = /tmp/mysql.sock1
port = 3306
bind_address = 0.0.0.0
datadir = /data1
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
skip_name_resolve = 1
log_error = error.log
pid-file = /data1/mysql.pid1


[mysqld2]
server-id = 12
socket = /tmp/mysql.sock2
port = 3307
bind_address = 0.0.0.0
datadir = /data2
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
skip_name_resolve = 1
log_error = error.log
pid-file = /data2/mysql.pid2


[mysqld3]
server-id = 13
socket = /tmp/mysql.sock3
port = 3308
bind_address = 0.0.0.0
datadir = /data3
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
skip_name_resolve = 1
log_error = error.log
pid-file = /data3/mysql.pid3


[mysqld4]
server-id = 14
socket = /tmp/mysql.sock4
port = 3309
bind_address = 0.0.0.0
datadir = /data4
user = mysql
performance_schema = off
innodb_buffer_pool_size = 32M
skip_name_resolve = 1
log_error = error.log
pid-file = /data4/mysql.pid4
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#
# 准备好数据目录，并初始化安装
#
[root@MyServer ~]> mkdir /data1
[root@MyServer ~]> mkdir /data2
[root@MyServer ~]> mkdir /data3
[root@MyServer ~]> mkdir /data4
[root@MyServer ~]> chown mysql.mysql /data{1..4}
[root@MyServer ~]> mysqld --initialize --user=mysql --datadir=/data1
#
# 一些日志输出，并提示临时密码，下同
#
[root@MyServer ~]> mysqld --initialize --user=mysql --datadir=/data2
[root@MyServer ~]> mysqld --initialize --user=mysql --datadir=/data3
[root@MyServer ~]> mysqld --initialize --user=mysql --datadir=/data4
# 安装后，需要检查error.log 确保没有错误出现
[root@MyServer ~]> cp /usr/local/mysql/support-files/mysqld_multi.server  /etc/init.d/mysqld_multid 
# 拷贝启动脚本，方便自启
[root@MyServer ~]> chkconfig mysqld_multid on
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[root@MyServer ~]> mysqld_multi  start
[root@MyServer ~]> mysqld_multi  report
Reporting MySQL servers
MySQL server from group: mysqld1 is running
MySQL server from group: mysqld2 is running
MySQL server from group: mysqld3 is running
MySQL server from group: mysqld4 is running
[root@MyServer ~]> netstat -tunlp | grep mysql
[root@MyServer ~]> netstat -tunlp | grep mysql
tcp        0      0 :::3307                     :::*                        LISTEN      6221/mysqld         
tcp        0      0 :::3308                     :::*                        LISTEN      6232/mysqld         
tcp        0      0 :::3309                     :::*                        LISTEN      6238/mysqld         
tcp        0      0 :::3306                     :::*                        LISTEN      6201/mysqld         

[root@MyServer ~]> mysql -u root -S /tmp/mysql.sock1 -p -P3306
#
# 使用-S /tmp/mysql.sock1 进行登录，并输入临时密码后，修改密码，下同
#
[root@MyServer ~]> mysql -u root -S /tmp/mysql.sock2 -p -P3307
[root@MyServer ~]> mysql -u root -S /tmp/mysql.sock3 -p -P3308
[root@MyServer ~]> mysql -u root -S /tmp/mysql.sock4 -p -P3309
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--
-- mysql1
--
mysql> show variables like "port"; 
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port          | 3306  |
+---------------+-------+
1 row in set (0.00 sec)

mysql> show variables like "socket";
+---------------+------------------+
| Variable_name | Value            |
+---------------+------------------+
| socket        | /tmp/mysql.sock1 |
+---------------+------------------+
1 row in set (0.01 sec)

mysql> show variables like "datadir";
+---------------+---------+
| Variable_name | Value   |
+---------------+---------+
| datadir       | /data1/ |
+---------------+---------+
1 row in set (0.00 sec)

--
-- 这样才能进行关闭数据库的操作
-- 和[mysqld_multi]中的user，pass(注意在5.7.9中不是password)对应起来 （类比[client]标签）
-- 一会测试federated链接，需要增加federated参数，并重启mysql2
--
mysql> create user 'multi_admin'@'localhost' identified by '123';
Query OK, 0 rows affected (0.00 sec)
mysql> grant shutdown on *.* to 'multi_admin'@'localhost';

--
-- mysql2, mysql3, mysql4 类似。可以看到与my.cnf中对应的port和socket
--

六. Federated测试

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--
-- mysql1 准备数据
--
mysql> show variables like "port"; 
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port          | 3306  |   -- mysql1 实例端口
+---------------+-------+
1 row in set (0.00 sec)

mysql> create database burn;
Query OK, 1 row affected (0.00 sec)

mysql> use burn;
Database changed

mysql> create table book (
    -> id int not null auto_increment,
    -> name varchar(128) not null,
    -> primary key(id)
    -> );
Query OK, 0 rows affected (0.20 sec)

mysql> insert into book values(1, "book1");
Query OK, 1 row affected (0.02 sec)

mysql> select * from book;
+----+-------+
| id | name  |
+----+-------+
|  1 | book1 |
+----+-------+
1 row in set (0.00 sec)

mysql> create user 'burn'@'127.0.0.1' identified by '123';
Query OK, 0 rows affected (0.00 sec)

mysql> grant select on burn.* to 'burn'@'127.0.0.1';
Query OK, 0 rows affected (0.00 sec)

mysql> show grants for 'burn'@'127.0.0.1';
+------------------------------------------------+
| Grants for burn@127.0.0.1                      |
+------------------------------------------------+
| GRANT USAGE ON *.* TO 'burn'@'127.0.0.1'       |
| GRANT SELECT ON `burn`.* TO 'burn'@'127.0.0.1' |
+------------------------------------------------+
2 rows in set (0.00 sec)
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--
-- mysql2 测试Federated
--
mysql> show variables like "port";
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port          | 3307  |  -- msyql2 实例端口
+---------------+-------+
1 row in set (0.01 sec)

mysql> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine             | Support | Comment                                                        | Transactions | XA   | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| MyISAM             | YES     | MyISAM storage engine                                          | NO           | NO   | NO         |
| CSV                | YES     | CSV storage engine                                             | NO           | NO   | NO         |
| PERFORMANCE_SCHEMA | YES     | Performance Schema                                             | NO           | NO   | NO         |
| BLACKHOLE          | YES     | /dev/null storage engine (anything you write to it disappears) | NO           | NO   | NO         |
| MRG_MYISAM         | YES     | Collection of identical MyISAM tables                          | NO           | NO   | NO         |
| InnoDB             | DEFAULT | Supports transactions, row-level locking, and foreign keys     | YES          | YES  | YES        |
| ARCHIVE            | YES     | Archive storage engine                                         | NO           | NO   | NO         |
| MEMORY             | YES     | Hash based, stored in memory, useful for temporary tables      | NO           | NO   | NO         |
| FEDERATED          | NO      | Federated MySQL storage engine                                 | NULL         | NULL | NULL       |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
--
-- federated 引擎没有打开
--
9 rows in set (0.00 sec)


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#
# 在[mysqld2]标签下面增加federated
#

[root@MyServer ~]> cat /etc/my.cnf
# ... 省略 ...
[mysqld2]
federated # 新增的配置项，表示打开federated引擎
# ... 省略 ...
[root@MyServer ~]> mysqld_multi stop 2
[root@MyServer ~]> mysqld_multi start 2   # 重启配置
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mysql> show variables like "port";
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| port          | 3307  |  -- msyql2 实例端口
+---------------+-------+
1 row in set (0.01 sec)

mysql> show engines;
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| Engine             | Support | Comment                                                        | Transactions | XA   | Savepoints |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
| MyISAM             | YES     | MyISAM storage engine                                          | NO           | NO   | NO         |
| CSV                | YES     | CSV storage engine                                             | NO           | NO   | NO         |
| PERFORMANCE_SCHEMA | YES     | Performance Schema                                             | NO           | NO   | NO         |
| BLACKHOLE          | YES     | /dev/null storage engine (anything you write to it disappears) | NO           | NO   | NO         |
| MRG_MYISAM         | YES     | Collection of identical MyISAM tables                          | NO           | NO   | NO         |
| InnoDB             | DEFAULT | Supports transactions, row-level locking, and foreign keys     | YES          | YES  | YES        |
| ARCHIVE            | YES     | Archive storage engine                                         | NO           | NO   | NO         |
| MEMORY             | YES     | Hash based, stored in memory, useful for temporary tables      | NO           | NO   | NO         |
| FEDERATED          | YES     | Federated MySQL storage engine                                 | NO           | NO   | NO         |
+--------------------+---------+----------------------------------------------------------------+--------------+------+------------+
9 rows in set (0.00 sec)
--
-- 显示 federated 已经启用
--
mysql> create database federated_test;
Query OK, 1 row affected (0.00 sec)

mysql> use federated_test;
Database changed

mysql> create table federated_table_1 (
    -> id int not null auto_increment,
    -> name varchar(128) not null,
    -> primary key(id)
    -> ) engine=federated
    -> connection='mysql://burn:123@127.0.0.1:3306/burn/book';
Query OK, 0 rows affected (0.04 sec)

mysql> select * from federated_table_1;
+----+-------+
| id | name  |
+----+-------+
|  1 | book1 |  -- 和 mysqld1 上的内容一致。
+----+-------+
1 row in set (0.00 sec)
--
-- 由于只有select权限，无法对该表进行insert操作
--
mysql> insert into  federated_table_1 values(2, "book2");
ERROR 1296 (HY000): Got error 10000 'Error on remote system: 1142: INSERT command denied to user 'burn'@'127.0.0.1' for table 'book'' from FEDERATED
---- The end of this article ----