多主一从mysql replication同步表的大胆尝

今天有人问我一个比较有趣的问题.能不能将不同机器上的不同库中的表同步到同一个机器的同一个库中.

表是不同的.而且对于slave这台机子来说,这些表只用来读.

同步不同库的表非常简单了,用
replicate-do-table=db_name.tbl_name

多个不同机子上的不同库的表同步到同一个机子的同一个库中,再加上下面这句.
replicate-rewrite-db=from_name->to_name

设置slave 上的my.cnf
cat my.cnf
[mysqld_multi]
mysqld = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
[mysqld1]
port     = 3306
socket   = /tmp/mysql.sock1
skip-locking
pid-file=/usr/local/mysql/data/test-db1a.pid
datadir = /usr/local/mysql/data
log=/usr/local/mysql/data/test-db1.log
user = mysql
log-slow-queries=/usr/local/mysql/data/slowquery1.log
long_query_time = 2
key_buffer = 256M
max_allowed_packet = 1M
table_cache = 512
sort_buffer_size = 2M
read_buffer_size = 2M
myisam_sort_buffer_size = 64M
thread_cache = 32
query_cache_size = 32M
thread_concurrency = 2
max_connections=500
server-id     = 2
master-host   =   192.168.0.1
master-user   =   ’replcate’
master-password =   ’1234567890’
master-port   = 3306
report-host = test-db3
master-connect-retry = 30
log-bin
log-slave-updates
replicate-rewrite-db=from_name->to_name
replicate-do-table=db_name.tbl_name
[mysqld2]
port = 3307
socket = /tmp/mysql.sock2
pid-file = /usr/local/mysql/data/test-db2b.pid
datadir = /usr/local/mysql/data
log=/usr/local/mysql/data/test-db2.log
user = mysql
log-slow-queries=/usr/local/mysql/data/slowquery2.log
long_query_time = 10
key_buffer = 128M
max_allowed_packet = 1M
table_cache = 512
sort_buffer_size = 1M
read_buffer_size = 1M
myisam_sort_buffer_size = 32M
thread_cache = 32
query_cache_size = 16M
thread_concurrency = 2
max_connections=300
server-id     = 2
master-host   =   192.168.0.2
master-user   =   ’repl’
master-password =   ’1234567890’
master-port   = 3307
report-host = test-db3
master-connect-retry = 30
log-bin
log-slave-updates
replicate-rewrite-db=from_name->to_name
replicate-do-table=db_name.tbl_name

好了,看看上面设置,明白了两个mysqld实例用了相同的库表文件,会不会有问题呢?
当然,使用不当的话会有问题,首先要符合两个实例读写的对象没有交叉.(同步过来的表唯一),其次选择合适的存储引擎,MYISM比innodb从理论上更适合这种应用．再次使用过程中对slave上的两个mysqld实例，只使用一个进行本机其他库表（非同步过来的）写操作．

ok,这种解决方案已通过测试．希望能够对你有所帮助．

原文：http://blog.chinaunix.net/u/4312/showart_320014.html