我搭建的是mysql 互为主从 复制

两台机器的mysql环境完全相同

第一部分测试：

B为master A为slave的同步测试

在B上创建表lian，并插入数据
mysql> create table lian (a int,b char(10));

mysql> insert into lian (a,b)values(22,'hahah');

mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| lian |
+----------------+
mysql> select * from lian;
+------+-------+
| a | b |
+------+-------+
| 22 | hahah |
+------+-------+

查看一下master-B的binlog日志，查看以上操作是否记录了日志：
cat mysql-bin.000002
.?Nh?@
stdtestcreate table lian (a int,b char(10))??Nl>
@
stdtestinsert into lian (a,b)values(22,'hahah')

现在查看slave-A的relay日志，发现日志已经同步了
[root@XKWB5510 var]# cat XKWB5510-relay-bin.000003
.?Nh?@
stdtestcreate table lian (a int,b char(10))??Nl>
@
stdtestinsert into lian (a,b)values(22,'hahah')

再在slave-A上看一下数据库是不是存在lian这个表：
mysql> use test;
Database changed
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| aniya |
| lian |
+----------------+
2 rows in set (0.00 sec)

现在说明数据B A 主 从 同步成功
---------------------------------------------------------------------------
第二部分测试：

A为master B为slave的同步测试

在A上创建表From246，并插入数据
mysql> use test;
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| A246 |
| aniya |
| lian |
+----------------+
3 rows in set (0.00 sec)

mysql> create table From246(Name varchar(255),Sex varchar(255),Age int(10));
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| A246 |
| From246 |
| aniya |
| lian |
+----------------+
4 rows in set (0.00 sec)

mysql> insert into From246 (Name,Sex,Age)values('Zhaoyj','Girl',24);
mysql> select * from From246;
+--------+------+------+
| Name | Sex | Age |
+--------+------+------+
| Zhaoyj | Girl | 24 |
+--------+------+------+
1 row in set (0.00 sec)

查看master-A的binlog日志,证明上述操作成功
[root@XKWB5510 var]# tail -1 mysql-bin.000002
testcreate table From246(Name varchar(255),Sex varchar(255),Age int(10))?N
?R@
std
testinsert into From246 (Name,Sex,Age)values('Zhaoyj','Girl',24)

查看master-A的日志状态
[root@XKWB5510 var]# /usr/local/mysql/bin/mysqlbinlog mysql-bin.000003 |tail -15
/*!*/;
# at 702
#110926 14:01:51 server id 1 end_log_pos 838 Query thread_id=5 exec_time=0 error_code=0
SET TIMESTAMP=1317016911/*!*/;
create table From246(Name varchar(255),Sex varchar(255),Age int(10))
/*!*/;
# at 838
#110926 14:02:05 server id 1 end_log_pos 966 Query thread_id=5 exec_time=0 error_code=0
SET TIMESTAMP=1317016925/*!*/;
insert into From246 (Name,Sex,Age)values('Zhaoyj','Girl',24)
/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;

查看relay-B的日志，同步日志成功
testcreate table From246(Name varchar(255),Sex varchar(255),Age int(10))?N
?R@
std
testinsert into From246 (Name,Sex,Age)values('Zhaoyj','Girl',24)[root@XKWB5705 var]

查看relay-B日志状态，可以看到日志已经同步
[root@XKWB5705 var]# /usr/local/mysql/bin/mysqlbinlog XKWB5705-relay-bin.000005|tail -13
/usr/local/mysql/bin/mysqlbinlog: Character set '#28' is not a compiled character set and is not specified in the '/usr/local/mysql/share/mysql/charsets/Index.xml' file
#110926 14:01:51 server id 1 end_log_pos 838 Query thread_id=5 exec_time=0 error_code=0
SET TIMESTAMP=1317016911/*!*/;
create table From246(Name varchar(255),Sex varchar(255),Age int(10))
/*!*/;
# at 853
#110926 14:02:05 server id 1 end_log_pos 966 Query thread_id=5 exec_time=0 error_code=0
SET TIMESTAMP=1317016925/*!*/;
insert into From246 (Name,Sex,Age)values('Zhaoyj','Girl',24)
/*!*/;
DELIMITER ;
# End of log file
ROLLBACK /* added by mysqlbinlog */;
/*!50003 SET COMPLETION_TYPE=@OLD_COMPLETION_TYPE*/;

但是数据却没有插入到relay-B的数据库
mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| lian |
+----------------+
1 row in set (0.00 sec)

当我删除master-A上的表时，relay-B日志也同步了
[root@XKWB5705 var]# tail -4 XKWB5705-relay-bin.000005
??N
S?@
std
testdrop table A246??N
T
@
std
testdrop table aniya??N
Sd
@
std
testdrop table lian??N
V?@
std
testdrop table From246

这是什么奇怪问题 ？？
------------------------------------------------------------------------------
问题排查：

首先在Master-A上用

show processlist; 查看下进程是否Sleep太多。发现很正常

show master status; 也正常

再跑到Slave上查看 show slave status; 也正常

当我手动从A导入B数据时，发现一个问题：
mysql> load table From246 from master;
ERROR 1115 (42000): Unknown character set: 'gbk'

怀疑：难道是因为字符串的问题导致AB主从复制失败 ？

通过show character set 命令查看到
master-A有gbk字符集而slave-B没有
mysql> show character set;
+----------+-----------------------------+---------------------+--------+
| Charset | Description | Default collation | Maxlen |
+----------+-----------------------------+---------------------+--------+
| dec8 | DEC West European | dec8_swedish_ci | 1 |
| cp850 | DOS West European | cp850_general_ci | 1 |
| hp8 | HP West European | hp8_english_ci | 1 |
| koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 |
| latin1 | cp1252 West European | latin1_swedish_ci | 1 |
| latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 |
| swe7 | 7bit Swedish | swe7_swedish_ci | 1 |
| ascii | US ASCII | ascii_general_ci | 1 |
| hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 |
| koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 |
| greek | ISO 8859-7 Greek | greek_general_ci | 1 |
| cp1250 | Windows Central European | cp1250_general_ci | 1 |
| gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 |
| latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 |
| armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 |
| utf8 | UTF-8 Unicode | utf8_general_ci | 3 |
| cp866 | DOS Russian | cp866_general_ci | 1 |
| keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 |
| macce | Mac Central European | macce_general_ci | 1 |
| macroman | Mac West European | macroman_general_ci | 1 |
| cp852 | DOS Central European | cp852_general_ci | 1 |
| latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 |
| cp1251 | Windows Cyrillic | cp1251_general_ci | 1 |
| cp1256 | Windows Arabic | cp1256_general_ci | 1 |
| cp1257 | Windows Baltic | cp1257_general_ci | 1 |
| binary | Binary pseudo charset | binary | 1 |
| geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 |
+----------+-----------------------------+---------------------+--------+
27 rows in set (0.00 sec)

那现在应该是在启动mysql的时候统一他们的字符集
master-A : [root@XKWB5510 var]# /usr/local/mysql/bin/mysqld_safe --default-character-set=latin1 &
slave-B : [root@XKWB5705 var]# /usr/local/mysql/bin/mysqld_safe --default-character-set=latin1 &

再次在B上从A导入数据：
mysql> show tables;
Empty set (0.00 sec)

mysql> load table From246 from master;
Query OK, 0 rows affected (0.01 sec)

mysql> show tables;
+----------------+
| Tables_in_test |
+----------------+
| From246 |
+----------------+
1 row in set (0.00 sec)

现在字符集的问题解决了

---------------------------------------------------------------

现在手动启动一下“将日志应用于数据库”的线程：SLAVE start SQL_THREAD
和“把master段的日志写到本地”的线程：SLAVE start IO_THREAD

发现同步数据还是失败，那说明不是线程的问题

如果发现 Seconds_Behind_Master 为 (null)
解决：
stop slave;
set global sql_slave_skip_counter =1 ;
start slave;
之后Slave会和Master去同步 主要看Seconds_Behind_Master是否为0，直到为0时就已经同步了。

-----------------------------------
slave B机器上master.info信息，与master A上的信息是否是同步的

mater A：
mysql> show master status/G;
*************************** 1. row ***************************
File: mysql-bin.000004
Position: 808
Binlog_Do_DB: test
Binlog_Ignore_DB: mysql
1 row in set (0.00 sec)

slave B：
[root@XKWB5705 var]# cat master.info
15
mysql-bin.000004
808
211.100.97.246
repl2
123456
3306
60
0

从以上可以看到是同步的

作者“ANLJF的专栏”