这里说的是innodb类型的死锁！

网上找了好多东西 各种命令查看死锁信息，后面这条能用：

show engine innodb status;（根据mysql版本而异）

这命令在mysql命令行执行后如果有死锁

会出现下面这一块：

------------------------
LATEST DETECTED DEADLOCK
------------------------

然后你可以根据这块内容找到你引起死锁的语句。

然后解决它，

我这次的死锁是因为，

有这么一条语句

update 表名 set xx=xxx where xxx=xxx！

其中xxx没有索引！

innodb是行级锁，但是mysql的机制是用索引来找到该行，如果你那个where字段没有索引，那么mysql就找不到那一行，就会锁整张表了

这样后面的访问就会引发死锁！

给xxx字段加上索引

附上异常信息：

Caused by: org.springframework.dao.DeadlockLoserDataAccessException: SqlMapClient operation; SQL [];   
--- The error occurred while applying a parameter map.  
--- Check the point.updatePointAccount-InlineParameterMap.  
--- Check the statement (update failed).  
--- Cause: com.mysql.jdbc.exceptions.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction; nested exception is com.ibatis.common.jdbc.exception.NestedSQLException:   
--- The error occurred while applying a parameter map.  
--- Check the point.updatePointAccount-InlineParameterMap.  
--- Check the statement (update failed).  
--- Cause: com.mysql.jdbc.exceptions.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
    at org.springframework.jdbc.support.SQLErrorCodeSQLExceptionTranslator.translate(SQLErrorCodeSQLExceptionTranslator.java:300)
    at org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:212)
    at org.springframework.orm.ibatis.SqlMapClientTemplate.update(SqlMapClientTemplate.java:411)
    at com.hsd.popularize.dao.BaseDaoImpl.update(BaseDaoImpl.java:162)
    ... 87 more
Caused by: com.ibatis.common.jdbc.exception.NestedSQLException:   
--- The error occurred while applying a parameter map.  
--- Check the point.updatePointAccount-InlineParameterMap.  
--- Check the statement (update failed).  
--- Cause: com.mysql.jdbc.exceptions.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
    at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeUpdate(GeneralStatement.java:91)
    at com.ibatis.sqlmap.engine.impl.SqlMapExecutorDelegate.update(SqlMapExecutorDelegate.java:505)
    at com.ibatis.sqlmap.engine.impl.SqlMapSessionImpl.update(SqlMapSessionImpl.java:90)
    at org.springframework.orm.ibatis.SqlMapClientTemplate$10.doInSqlMapClient(SqlMapClientTemplate.java:413)
    at org.springframework.orm.ibatis.SqlMapClientTemplate.execute(SqlMapClientTemplate.java:209)
    ... 89 more
Caused by: com.mysql.jdbc.exceptions.MySQLTransactionRollbackException: Deadlock found when trying to get lock; try restarting transaction
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:941)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2870)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1573)
    at com.mysql.jdbc.ServerPreparedStatement.serverExecute(ServerPreparedStatement.java:1169)
    at com.mysql.jdbc.ServerPreparedStatement.executeInternal(ServerPreparedStatement.java:693)
    at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:794)
    at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.execute(NewProxyPreparedStatement.java:989)
    at sun.reflect.GeneratedMethodAccessor51.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.ibatis.common.jdbc.logging.PreparedStatementLogProxy.invoke(PreparedStatementLogProxy.java:62)
    at com.sun.proxy.$Proxy20.execute(Unknown Source)
    at com.ibatis.sqlmap.engine.execution.SqlExecutor.executeUpdate(SqlExecutor.java:81)
    at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.sqlExecuteUpdate(GeneralStatement.java:200)
    at com.ibatis.sqlmap.engine.mapping.statement.GeneralStatement.executeUpdate(GeneralStatement.java:78)
    ... 93 more

mysql 的一个死锁问题解决