Before Image Task Settings - AWS Database Migration Service

Before Image Task Settings

When writing CDC updates to a data-streaming target like Kinesis or Kafka, you can view a source database row's original values before change by an update. To make this possible, AWS DMS populates a before image of update events based on data supplied by the source database engine.

BeforeImageSettings – Adds a new JSON attribute to every update operation with values collected from the source database system.

Note

Apply BeforeImageSettings to full load plus CDC tasks (which migrate existing data and replicate ongoing changes), or to CDC only tasks (which replicate data changes only). Don't apply BeforeImageSettings to tasks that are full load only.

  • EnableBeforeImage – Enables before imaging when set to true. The default is false.

  • FieldName – Assigns a name to the new JSON attribute. When EnableBeforeImage is true, FieldName is required and can't be empty.

  • ColumnFilter – Specifies a column to add by using before imaging. To add only columns that are part of the table's primary keys, use the default value, pk-only. To add only columns that are not of LOB type, use non-lob. To add any column that has a before image value, use all.

For example:

"BeforeImageSettings": { "EnableBeforeImage": true, "FieldName": "before-image", "ColumnFilter": "pk-only" }

For information on before image settings for Kinesis, including additional table mapping settings, see Using a Before Image to View Original Values of CDC Rows for a Kinesis Data Stream as a Target.

For information on before image settings for Kafka, including additional table mapping settings, see Using a Before Image to View Original Values of CDC Rows for Apache Kafka as a Target.