# 增量同步失败报错，关键词"service INCREMENT failed, cause by: update xx.xxx failed: ERROR: Write to replicated table returned different results from the DataNodes on current DN:dn_\*\*\* and previous DN:dn_\*\*\*"
#### 场景描述
Oracle为源端数据库增量同步阶段报错，同步日志界面提示：service INCREMENT failed, cause by: update xx.xxx failed: ERROR: Write to replicated table returned different results from the DataNodes on current DN:dn_\*\*\* and previous DN:dn_\*\*\*.
#### 可能原因
目标库为无主键复制表,drs不支持无主键复制表的更新。
#### 解决方案
请联系客户修改目标库表结构为主键表或者修改成非复制表。