主从(master/slave)默认引擎不一致导致复制失败解决_MySQL

主从(master/slave)默认引擎不一致导致复制失败解决

同事告知，一台slave服务器复制中断，查看slave服务器,如下错误

Error &＃39;Specified key was too long; max keylength is 1000 bytes&＃39; on query

mysql> show slave status /G;

*************************** 1. row***************************

Slave_IO_State: Waiting formaster to send event

Master_Host: 192.xxx.xxx.146

Master_User: repl

Master_Port: 3306

Connect_Retry: 60

Master_Log_File: mysql-bin.004369

Read_Master_Log_Pos: 717957570

Relay_Log_File: relay-bin.013649

Relay_Log_Pos: 571890895

Relay_Master_Log_File: mysql-bin.004368

Slave_IO_Running: Yes

Slave_SQL_Running: No

Replicate_Do_DB:

Replicate_Ignore_DB:

Replicate_Do_Table:

Replicate_Ignore_Table:

Replicate_Wild_Do_Table:

Replicate_Wild_Ignore_Table:

Last_Errno: 1071

Last_Error: Error &＃39;Specified key was too long; max key length is 1000 bytes&＃39; onquery. Default database: &＃39;analyse_xxx&＃39;. Query: &＃39;CREATE TABLE`meta_topic_scan` ( `domain` varchar(200) NOT NULL COMMENT &＃39;&＃39; , `topic_name`varchar(200) NOT NULL COMMENT &＃39;&＃39; , `topic_url` varchar(200) NOT NULL COMMENT &＃39;&＃39;, `topic_pv` int NULL DEFAULT 0 COMMENT &＃39;&＃39; , `topic_uv` int NULL DEFAULT 0COMMENT &＃39;&＃39; , `pv` int NULL DEFAULT 0 COMMENT &＃39;&＃39; , `uv` int NULL DEFAULT 0COMMENT &＃39;&＃39; , `shopcart_pv` int NULL DEFAULT 0 COMMENT &＃39;&＃39;

Skip_Counter: 0

Exec_Master_Log_Pos: 571890750

Relay_Log_Space: 1802530754

Until_Condition: None

Until_Log_File:

Until_Log_Pos: 0

Master_SSL_Allowed: No

Master_SSL_CA_File:

Master_SSL_CA_Path:

Master_SSL_Cert:

Master_SSL_Cipher:

Master_SSL_Key:

Seconds_Behind_Master: NULL

Master_SSL_Verify_Server_Cert: No

Last_IO_Errno: 0

Last_IO_Error:

Last_SQL_Errno: 1071

Last_SQL_Error: Error &＃39;Specified keywas too long; max key length is 1000 bytes&＃39; on query. Default database:&＃39;analyse_product&＃39;. Query: &＃39;CREATE TABLE

`meta_topic_scan` ( `domain` varchar(200)NOT NULL COMMENT &＃39;&＃39; , `topic_name` varchar(200) NOT NULL COMMENT &＃39;&＃39; ,`topic_url` varchar(200) NOT NULL COMMENT &＃39;&＃39; , `topic_pv` int NULL DEFAULT 0COMMENT &＃39;&＃39; , `topic_uv` int NULL DEFAULT 0 COMMENT &＃39;&＃39; , `pv` int NULL DEFAULT 0COMMENT &＃39;&＃39; , `uv` int NULL DEFAULT 0 COMMENT &＃39;&＃39; , `shopcart_pv` int NULL DEFAULT0

1 row in set (0.00 sec)

ERROR:

No query specified

创建表竟然失败,索引长度超过了最大值1000，看看报错日志

[root@db~]# tail -n 500 /my/data/mysql/dbxxxxxx.err

130606 10:57:20 [ERROR] Slave SQL: Error&＃39;Specified key was too long; max key length is 1000 bytes&＃39; on query. Defaultdatabase: &＃39;analyse_xxx&＃39;. Query: &＃39;CREATE TABLE

`meta_topic_scan` ( `domain` varchar(200)NOT NULL COMMENT &＃39;&＃39; , `topic_name` varchar(200) NOT NULL COMMENT &＃39;&＃39; ,`topic_url` varchar(200) NOT NULL COMMENT &＃39;&＃39; , `topic_pv` int

NULL DEFAULT 0 COMMENT &＃39;&＃39; , `topic_uv` intNULL DEFAULT 0 COMMENT &＃39;&＃39; , `pv` int NULL DEFAULT 0 COMMENT &＃39;&＃39; , `uv` int NULLDEFAULT 0 COMMENT &＃39;&＃39; , `shopcart_pv` int NULL DEFAULT 0

130606 10:57:20 [Warning] Slave: Specifiedkey was too long; max key length is 1000 bytes Error_code: 1071

130606 10:57:20 [ERROR] Error runningquery, slave SQL thread aborted. Fix the problem, and restart the slave SQLthread with "SLAVE START". We stopped at log &＃39;mysql-bin.004368&＃39; position571890750

日志显示在上午10点57分建表失败，很明显的错误，索引长度超过了1000字节，然后告知同事，创建表索引长度超过了1000字节，导致slave io_thread中断。然后同事很奇怪的说，上午master上面创建表没问题，顺利的创建，为什么在slave上复制报错？

后来通过在slave上手工建表发现master和slave 默认存储引擎不一致，不一致会引起中断？是的，建表语句是否明确指定使用那种存储引擎如下语句

CREATE TABLE `meta_topic_scan` (

`domain` varchar(200) NOT NULL ,

`topic_name` varchar(200) NOT NULL,

`topic_url` varchar(200) NOT NULL ,

`topic_pv` int(11) DEFAULT &＃39;0&＃39;,

`topic_uv` int(11) DEFAULT &＃39;0&＃39;,

PRIMARY KEY (`domain`,`topic_name`,`topic_url`)

);

如果在建表时不指定存储引擎，在master上默认引擎是innodb，创建的表就是innodb类型，写到binlog日志里的语句是什么格式呢？

我们利用mysqlbinlog去查找这条语句，如下格式去分析

[root@aeolus1 ~]# mysqlbinlog -uroot--start-position=1914 /usr/local/mysql/data/mysql-bin.000014

发现建表语句以这样的格式写入binlog二进制日志中

CREATE TABLE `meta_topic_scan` (

`domain` varchar(200) NOT NULL comment &＃39;&＃39;,

`topic_name` varchar(200) NOT NULL comment &＃39;&＃39;,

`topic_url` varchar(200) NOT NULL comment &＃39;&＃39;,

`topic_pv` int(11) DEFAULT &＃39;0&＃39; comment &＃39;&＃39;,

`topic_uv` int(11) DEFAULT &＃39;0&＃39; comment &＃39;&＃39;,

PRIMARY KEY (`domain`,`topic_name`,`topic_url`)

);

这样io_thread把binlog从master服务器传送到slave，sql_thread在slave上执行此语句，由此可知slave默认是什么引擎，就创建默认引擎的表。由于slave默认是mysiam，索引在innodb和mysiam两个引擎上索引长度不一样，导致主从复制中断。

修改my.cnf，改默认引擎innodb，重启服务(业务不是很重要，允许重启)，ok。如果不允许重启，那就在slave上创建表，然后跳过出错的event，在维护窗口再重启生效