Data messages
This topic describes the structure and content of the Data messages produced by the Replicate Amazon MSK endpoint.
Field | Type | Description |
---|---|---|
headers |
Structure | Information about the current record. |
operation |
Enum | The operation type. Full Load (Replicate transfers the existing records from source table) REFRESH – insert of a record during Full Load stage. CDC (Replicate transfers the changes from source table) INSERT – insertion of new record UPDATE – update of existing record DELETE – deletion of a record |
changeSequence |
String |
A monotonically increasing change sequencer that is common to all change tables of a task. Use this field to order the records in chronological order. Applicable to CDC operations. |
timestamp |
String |
The original change UTC timestamp. Applicable to CDC operations. |
streamPosition |
String |
The source CDC stream position. Applicable to CDC operations. |
transactionId |
String |
The ID of the transaction that the change record belongs to. Use this field to gather all changes of a specific transaction. Applicable to CDC operations. |
changeMask |
String |
Indicates which data columns were changed in the source table. The change mask is a string of hexadecimal digits, representing a bitmask of data columns in little-endian order. The bit position in the change mask is based on the ordinal of the column in the metadata message of that table. This means that if there are 10 data columns, they occupy bits 0 to 9 in the bitmask. If UPDATE mask is 0B hexadecimal, which is 1011 binary – it means that the columns at ordinals 1, 2 and 4 were changed. The following describes the bit semantics:
Information note
LOB columns are not included in the changeMask bit. |
columnMask |
String |
Indicates which data columns are present in the message. Usually, this will include all of the table columns. Information note
When replicating from an Oracle source without full supplemental logging, some columns might not be present in the data, since they could not be replicated. The column mask is a string of hexadecimal digits, representing a bitmask of data columns in little-endian order. The bit position in the column mask is based on the ordinal of the column in the metadata message for that table. This allows the applier to distinguish a null value that is the actual value of the column, from a null value that represents a column which could not be replicated from the source database. |
externalSchemaId |
String |
The Schema ID. This will only be displayed if the Include external Schema IDheader check box is selected. As the Schema ID changes whenever a DDL is performed on the source table, consumer applications can use this information to determine if the message schema has changed. |
transactionEventCounter |
Long |
The sequence number of the current operation in the transaction. This can be used to determine the order of operations within a transaction. |
transactionLastEvent |
Boolean |
"True" indicates that it is the final record in the transaction whereas "False" indicates that not all of the records have been processed. |
data |
Structure | The data of the table record |
{columns} |
The column names and values in the current record. | |
beforeData |
Structure | The data of the table record, before the change |
{columns} |
The column names and values, before the change. Applicable to UPDATE operation. |