CREATE SCHEDULE FOR CHANGEFEED

CREATE SCHEDULE FOR CHANGEFEED allows you to create a scheduled changefeed to export data out of CockroachDB. Scheduled changefeeds have the scale, observability, and endpoint sink options that changefeed jobs include, with the convenience of setting a regular schedule. A changefeed job created with CREATE SCHEDULE FOR CHANGEFEED performs a one-time table scan using the functionality to create an export of your table data.

For more detail on using changefeeds to create an export of your table data, see .

Required privileges

You can a user the CHANGEFEED privilege to allow them to create changefeeds on a specific table:

GRANT CHANGEFEED ON TABLE example_table TO user;

When you grant a user the CHANGEFEED privilege on a set of tables, they can:

• Create changefeeds on the target tables even if the user does not have the or the SELECT privilege on the tables.
• Manage the changefeed jobs running on the tables using the , , , and commands.

These users will be able to create changefeeds, but they will not be able to run a SELECT query on that data directly. However, they could still read this data indirectly if they have read access to the .

To restrict a user’s access to changefeed data and sink credentials, enable the changefeed.permissions.require_external_connection_sink.enabled cluster setting. When you enable this setting, users with the on a set of tables can only create changefeeds into .

You can add CHANGEFEED to the user or role’s with :

ALTER DEFAULT PRIVILEGES GRANT CHANGEFEED ON TABLES TO user;

Privilege model

For fine-grained access control, we recommend using the system-level privileges CHANGEFEED and CONTROLJOB / VIEWJOB.

The following summarizes the operations users can run when they have changefeed privileges on a table:

Granted privileges	Usage
CHANGEFEED	Create changefeeds on tables. View and manage changefeed jobs on tables.
CHANGEFEED + on external connection	Create changefeeds on tables to an external connection URI. Manage changefeed jobs on tables. Note: If you need to manage access to changefeed sink URIs, set the changefeed.permissions.require\_external\_connection\_sink.enabled=true cluster setting. This will mean that users with these privileges can only create changefeeds on external connections.
SELECT	Create a sinkless changefeed that emits messages to a SQL client.
DeprecatedCONTROLCHANGEFEED role option + SELECT	Create changefeeds on tables. Users with the CONTROLCHANGEFEED role option must have SELECT on each table, even if they are also granted the CHANGEFEED privilege. The CONTROLCHANGEFEED role option will be removed in a future release. We recommend using the CHANGEFEED and CONTROLJOB/ VIEWJOB for fine-grained access control.
admin	Create, view, and manage changefeed jobs.

Synopsis

Parameters

Parameter	Description
IF NOT EXISTS	A scheduled changefeed should not be created if the schedule\_label already exists. You will receive an error if the schedule label already exists, or if schedule\_label is not defined when using IF NOT EXISTS.
schedule\_label	The name for the scheduled changefeed. This is optional and does not need to be unique. If you do not define a name, the label will default to CHANGEFEED with the timestamp of when you created the schedule.
changefeed\_targets	The tables to target with the changefeed. For example, movr.users, movr.rides.
changefeed\_sink	The .
changefeed\_option	The to control the behavior of your changefeed. For example, WITH format = csv, full\_table\_name. See Changefeed options for a list of available options.
target\_list	The columns to emit data from if you’re using a expression.
insert\_target	The target tables for the changefeed if you’re using a expression.
where\_clause	An optional WHERE clause to apply filters to the table if you’re using a expression.
crontab	The frequency of the changefeed. The schedule is specified as a STRING in crontab format. All times in UTC. For example, '@daily', '@hourly', '1 0 \* \* \*'.
schedule\_option	The schedule options to control the schedule’s behavior. For example, first\_run = now. See Schedule options.

Changefeed options

You can include the changefeed options listed on the page to modify the behavior of your changefeed. The following options are not compatible with scheduled changefeeds:

• diff
• end_time
• mvcc_timestamp
• resolved
• updated

Scheduled changefeeds have the option included implicitly. You cannot specify initial_scan as 'yes' or 'no'.

Schedule options

Option	Value	Description
first\_run	/ now	Execute the first run of the schedule at this time. If you do not specify first\_run, the schedule will execute based on the next RECURRING time set by the crontab.
on\_execution\_failure	retry / reschedule / pause	Determine how the schedule handles an error. retry: Retry the changefeed immediately. reschedule: Reschedule the changefeed based on the RECURRING expression. pause: Pause the schedule. This requires that you manually. Default:reschedule
on\_previous\_running	start / skip / wait	Control whether the changefeed schedule should start a changefeed if the previous scheduled changefeed is still running. start: Start the new changefeed anyway, even if the previous one is running. skip: Skip the new changefeed and run the next changefeed based on the RECURRING expression. wait: Wait for the previous changefeed to complete. Default:wait

To avoid multiple clusters running the same schedule concurrently, changefeed schedules will when onto a different cluster or after has completed.

Examples

Before running any of the examples in this section, it is necessary to enable the kv.rangefeed.enabled cluster setting. If you are working on a CockroachDB Standard or Basic cluster, this cluster setting is enabled by default.

The page provides detail on the available sinks for your change data messages and connection URIs. We recommend using to interact with external sinks. The examples in this section use an external connection URI for the changefeed sink.

Create a scheduled changefeed

The following statement sets up a scheduled changefeed named users_rides_nightly that will send changefeed messages in CSV format 1 minute past midnight every night. As soon as the statement is run, the first changefeed run will execute immediately:

CREATE SCHEDULE users_rides_nightly FOR CHANGEFEED users, rides INTO 'external://kafka-sink' WITH format=csv RECURRING '1 0 * * *' WITH SCHEDULE OPTIONS first_run=now, on_execution_failure=retry, on_previous_running=skip;

The control the schedule’s behavior:

• If it runs into an error, on_execution_failure=retry will ensure that the schedule retries the changefeed immediately.
• If the previous scheduled changefeed is still running, on_previous_running=skip will skip a new changefeed at the next scheduled time.

The output will confirm that the changefeed has added the initial_scan = 'only' option implicitly:

     schedule_id     |     label     | status |           first_run           | schedule  |                                                      changefeed_stmt
---------------------+---------------+--------+-------------------------------+-----------+---------------------------------------------------------------------------------------------------------------------------------------------------------
  947257854259855361 | users_nightly | ACTIVE | 2024-02-28 20:02:35.716699+00 | 1 0 * * * | CREATE CHANGEFEED FOR TABLE movr.public.users, TABLE movr.public.rides INTO 'external://kafka-sink' WITH OPTIONS (format = 'csv', initial_scan = 'only')
(1 row)

NOTICE: added missing initial_scan='only' option to schedule changefeed

Create a scheduled changefeed with CDC queries

You can use CDC queries with scheduled changefeeds to define expression syntax that selects columns and applies filters to further restrict or transform the data in your changefeed messages. When you add this expression syntax to your changefeed statement, you can only target one table.

For guidance on syntax and more example use cases, see .

This scheduled changefeed filters for the usage of promotion codes in the database and sends the changefeed messages on a daily basis:

CREATE SCHEDULE promo_code FOR CHANGEFEED INTO 'external://kafka-sink' AS SELECT user_id, usage_count FROM movr.user_promo_codes WHERE usage_count > 1 RECURRING '@daily' WITH SCHEDULE OPTIONS first_run=now, on_execution_failure=reschedule, on_previous_running=skip;

View scheduled changefeed details

To all scheduled changefeeds:

SHOW SCHEDULES FOR CHANGEFEED;

To view the details of only running scheduled changefeeds:

SHOW RUNNING SCHEDULES FOR CHANGEFEED;

To view the details of only paused scheduled changefeeds:

SHOW PAUSED SCHEDULES FOR CHANGEFEED;

To view the details of a specific scheduled changefeed:

SHOW SCHEDULE {schedule ID};

To a scheduled changefeed:

PAUSE SCHEDULE {schedule ID};

To a scheduled changefeed:

RESUME SCHEDULE {schedule ID};

To a scheduled changefeed:

DROP SCHEDULE {schedule ID};

To see the full for the scheduled changefeed:

SHOW CREATE SCHEDULE {schedule ID};

See also