Adding or removing a changefeed

ADD CHANGEFEED <name> WITH (<option> = <value>[, ...]): Adds a changefeed with the specified name and options.

Changefeed options

• MODE: Operation mode. Specifies what to write to a changefeed each time table data is altered.
  • KEYS_ONLY: Only the primary key components and change flag are written.
  • UPDATES: Updated column values that result from updates are written.
  • NEW_IMAGE: Any column values resulting from updates are written.
  • OLD_IMAGE: Any column values before updates are written.
  • NEW_AND_OLD_IMAGES: A combination of NEW_IMAGE and OLD_IMAGE modes. Any column values prior to and resulting from updates are written.
• FORMAT: Data write format.
  • JSON: Write data in JSON format.
  • DEBEZIUM_JSON: Write data in the Debezium-like JSON format.
• VIRTUAL_TIMESTAMPS: Enabling/disabling virtual timestamps. Disabled by default.
• RETENTION_PERIOD: Record retention period. The value type is Interval and the default value is 24 hours (Interval('PT24H')).
• TOPIC_MIN_ACTIVE_PARTITIONS: The number of topic partitions. By default, the number of topic partitions is equal to the number of table partitions.
• INITIAL_SCAN: Enables/disables initial table scan. Disabled by default.

The code below adds a changefeed named updates_feed, where the values of updated table columns will be exported in JSON format:

ALTER TABLE `series` ADD CHANGEFEED `updates_feed` WITH (
    FORMAT = 'JSON',
    MODE = 'UPDATES'
);

Records in this changefeed will be stored for 24 hours (default value). The code in the following example will create a changefeed with a record retention period of 12 hours:

ALTER TABLE `series` ADD CHANGEFEED `updates_feed` WITH (
    FORMAT = 'JSON',
    MODE = 'UPDATES',
    RETENTION_PERIOD = Interval('PT12H')
);

The example of creating a changefeed with enabled virtual timestamps:

ALTER TABLE `series` ADD CHANGEFEED `updates_feed` WITH (
    FORMAT = 'JSON',
    MODE = 'UPDATES',
    VIRTUAL_TIMESTAMPS = TRUE
);

Example of creating a changefeed with initial scan:

ALTER TABLE `series` ADD CHANGEFEED `updates_feed` WITH (
    FORMAT = 'JSON',
    MODE = 'UPDATES',
    INITIAL_SCAN = TRUE
);

DROP CHANGEFEED: Deletes the changefeed with the specified name. The code below deletes the updates_feed changefeed:

ALTER TABLE `series` DROP CHANGEFEED `updates_feed`;