Change Data Capture (CDC) Configuration

The cdcSettings and cdcSnapshotSettings enable and pass configuration info to the CDC API’s.

Field	Type	Description
cdcSettings	object	See cdcSettings for more information.
cdcSnapshotSettings	object	See cdcSnapshotSettings for more information.

cdcSettings

The cdcSettings object contains the following properties:

Parameter	Type	Description
keys	list	The column or combination of columns that uniquely identify a row in the source data. This is used to identify which CDC events apply to specific records in the target table.
sequence_by	str	The column name specifying the logical order of CDC events in the source data. Delta Live Tables uses this sequencing to handle change events that arrive out of order.
scd_type	string	Whether to store records as SCD type 1 or SCD type 2. Set to 1 for SCD type 1 or 2 for SCD type 2.
apply_as_deletes	string	(optional) Specifies when a CDC event should be treated as a DELETE rather than an upsert.
where	string	(optional) Filter the rows by a condition.
ignore_null_updates	boolean	(optional) Allow ingesting updates containing a subset of the target columns. When a CDC event matches an existing row and ignore_null_updates is True, columns with a null retain their existing values in the target. This also applies to nested columns with a value of null. When ignore_null_updates is False, existing values are overwritten with null values.
except_column_list	list	(optional) A list of columns to exclude from the upsert into the target table.
track_history_column_list track_history_except_column_list	list	A subset of output columns to be tracked for history in the target table. Use track_history_column_list to specify the complete list of columns to be tracked. Use track_history_except_column_list to specify the columns to be excluded from tracking.

cdcSnapshotSettings

The cdcSnapshotSettings object contains the following properties:

Parameter	Type	Description
keys	list	The column or combination of columns that uniquely identify a row in the source data. This is used to identify which CDC events apply to specific records in the target table.
snapshotType	str	The type of snapshot to process. Set to periodic for periodic snapshots or historical for historical snapshots (refer to CDC Historical Snapshot Source Configuration for which type to use). Note that historical snapshot types are not supported in flow data flow types.
scd_type	string	Whether to store records as SCD type 1 or SCD type 2. Set to 1 for SCD type 1 or 2 for SCD type 2.
sourceType	string	The type of source to ingest the snapshots from. Set to file for file based sources.
source	object	The source to ingest the snapshots from. This is required for historical snapshot types. See CDC Historical Snapshot Source Configuration for more information.
track_history_column_list	list	(optional) A subset of output columns to be tracked for history in the target table. Use this to specify the complete list of columns to be tracked. This cannot be used in conjunction with track_history_except_column_list.
track_history_except_column_list	list	(optional) A subset of output columns to be excluded from history tracking in the target table. Use this to specify which columns should not be tracked. This cannot be used in conjunction with track_history_column_list.

CDC Historical Snapshot Source Configuration

The source object contains the following properties for file based sources:

Parameter	Type	Description
format	string	The format of the source data. E.g. supported formats are table, parquet, csv, json. All formats supported by spark see PySpark Data Sources API.
path	string	The location to load the source data from. This can be a table name or a path to a a file or directory with multiple snapshots. A placeholder {version} can be used in this path which will be substituted with the version value in run time.
versionType	string	The type of versioning to use. Can be either int or datetime.
datetimeFormat	string	(conditional) Required if versionType is datetime. The format of startingVersion datetime value.
microSecondMaskLength	integer	(optional) WARNING: Edge Cases Only! - Specify this if your versionType is datetime and your filename includes microsends, but not the full 6 digits. The number of microsecond digits to included at the end of the datetime value. - The default value is 6.
startingVersion	string or integer	(optional) The version to start processing from.
readerOptions	object	(optional) Additional options to pass to the reader.
schemaPath	string	(optional) The schema path to use for the source data.
selectExp	list	(optional) A list of select expressions to apply to the source data.
filter	string	(optional) A filter expression to apply to the source data. This filter is applied to the dataframe as a WHERE clause when the source is read. A placeholder {version} can be used in this filter expression which will be substituted with the version value in run time.
recursiveFileLookup	boolean	(optional) When set to true, enables recursive directory traversal to find snapshot files. This should be used when snapshots are stored in a nested directory structure such as Hive-style partitioning (e.g., /data/{version}/file.parquet). When set to false (default), only files in the immediate directory are searched. Default: false.

Note

If recursiveFileLookup is set to true, ensure that the path parameter is specified in a way that is compatible with recursive directory traversal. I.e. the {version} placeholder is used in the path and not the filename.

The source object contains the following properties for table based sources:

Parameter	Type	Description
table	string	The table name to load the source data from.
versionColumn	string	The column name to use for versioning.
startingVersion	string or integer	(optional) The version to start processing from.
selectExp	list	(optional) A list of select expressions to apply to the source data.