双向同步时库select报错

我做了双向同步，其中一端的库使用的是阿里云的RDS，做数据同步时，发生node报错，且同步未成功。报错如下：

pid:2 nid:3 exception:setl:com.alibaba.otter.node.etl.load.exception.LoadException: java.util.concurrent.ExecutionException: com.alibaba.otter.node.etl.load.exception.LoadException: com.alibaba.otter.node.etl.load.exception.LoadException: com.alibaba.otter.node.etl.load.exception.LoadException: org.springframework.jdbc.BadSqlGrammarException: StatementCallback; bad SQL grammar [SELECT COUNT(_) FROM retl.retl_mark WHERE id BETWEEN 0 AND 999]; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: _SELECT command denied to user 'username'@'10.151.132.116' for table 'retl_mark'* at org.springframework.jdbc.support.SQLExceptionSubclassTranslator.doTranslate(SQLExceptionSubclassTranslator.java:94) at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:72) at org.springframework.jdbc.support.AbstractFallbackSQLExceptionTranslator.translate(AbstractFallbackSQLExceptionTranslator.java:80) at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:407) at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:456) at org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:464) at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:472) at org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:477) at org.springframework.jdbc.core.JdbcTemplate.queryForInt(JdbcTemplate.java:486) at com.alibaba.otter.node.etl.load.loader.db.interceptor.operation.AbstractOperationInterceptor.init(AbstractOperationInterceptor.java:76) at com.alibaba.otter.node.etl.load.loader.db.interceptor.operation.AbstractOperationInterceptor.updateMark(AbstractOperationInterceptor.java:148) at com.alibaba.otter.node.etl.load.loader.db.interceptor.operation.AbstractOperationInterceptor.transactionBegin(AbstractOperationInterceptor.java:119) at com.alibaba.otter.node.etl.load.loader.db.interceptor.operation.AbstractOperationInterceptor.transactionBegin(AbstractOperationInterceptor -------------------------------------分割线-----------------------------------------

我不太明白‘username’是我配置连接阿里RDS的账号，otter为什么要用这个账号去连接otter自己的库呢？还有，我明明使用是阿里RDS的外网连接地址，怎么回返回一个阿里代理层的内网地址10.151.132.116？

原提问者GitHub用户 Fredwt