DMS task is creating full row duplicates in target

Question

Hi,
I have a DMS task to move data from Oracle CDC to Redshift. (Full Load and ongoing changes). During the full load, the task just keeps on running and is not reaching a 100%.  In the target, I can see the row count is already 4 times the row count in the source. There are 4x full row duplicates in the target. Can anyone please guide what could be the issue here and how to debug?
thnx.

Answer

Hi ,

have you looked at the [DMS logs for the task](https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Monitoring.html)?

*AWS DMS restarts table loading from the beginning when it hasn't finished the initial load of a table. When a task is restarted, AWS DMS reloads tables from the beginning when the initial load didn't complete.*

As described [here](https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Troubleshooting.html#CHAP_Troubleshooting.General.RestartLoad).

[The recoverable error count ](https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Tasks.CustomizingTasks.TaskSettings.ErrorHandling.html) is by default -1 (restart indefinitely) so if any error happens the task might restart and reload all the tables. With no PK enforcing (as in Redshift) you will see the duplicates.

hope this helps

DMS task is creating full row duplicates in target

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