Data messages

This topic describes the structure and content of the data messages produced by the Google Cloud Pub/Sub target endpoint.

Data message
Field	Type	Description
schema (name)	String	The name of the source database schema containing the replicated source table(s).
table (name)	String	The name of the source table.
headers	Structure	Information about the current record.
operation (Operation)	Enum	The operation type. Full Load - Initial load of the source data to the target topic(s) REFRESH – Insertion of a record to the target during Full Load CDC - Applies source table changes to the relevant topic INSERT – Insertion of new target record UPDATE – Update of an existing target record DELETE – Deletion of a target record
changeSequence (Change Sequence)	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 only.
timestamp (Timestamp)	String	The original change UTC timestamp. Applicable to CDC operations only.
transactionId (Transaction ID)	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 only.
changeMask (Change Mask)	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: For INSERT records, all the inserted columns have the associated bits set. For DELETE records, only primary-key (or unique index) columns have the associated bits set. This allows an applier to construct a DELETE statement without having to find the primary key fields from another source. For UPDATE records, each column with a changed value will have the associated bit set. Information note LOB columns are not included in the changeMask bit.
columnMask (Column Mask)	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.
transactionEventCounter (Transaction Event Counter)	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 (Transaction Last Event)	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.

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