CREATE CHANGEFEED

The CREATE CHANGEFEED statement creates a new changefeed, which targets an allowlist of tables called “watched rows”. Every change to a watched row is emitted as a record in a configurable format (such as JSON, Avro, CSV, Parquet, or protobuf) to a configurable sink or directly to the SQL session. When a changefeed emits messages to a sink, it works as a job. You can create, pause, resume, alter, or cancel a changefeed job. To get started with changefeeds, refer to the Create and Configure Changefeeds page for important usage considerations. For details on how changefeeds emit messages, refer to the Changefeed Messages page. The examples on this page provide the foundational syntax of the CREATE CHANGEFEED statement. For examples on more specific use cases with changefeeds, refer to the following pages:

Cockroach Labs recommends monitoring your changefeeds to track retryable errors and protected timestamp usage. Refer to the Monitor and Debug Changefeeds page for more information.

Required privileges

As of v25.1, viewing and managing a changefeed job by users with the CHANGEFEED privilege is deprecated. This functionality of the CHANGEFEED privilege will be removed in a future release.We recommend transitioning users that need to view and manage running changefeed jobs to roles that own the jobs or granting them the VIEWJOB or CONTROLJOB privilege. For more details, refer to View and manage changefeed jobs.

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 depending on whether the assigned privileges are at the job or table level:

Granted privileges	Usage
`CHANGEFEED`	Create changefeeds on tables. For details, refer to `CHANGEFEED` privilege. Deprecated: View and manage changefeed jobs on tables. Instead, transition users that need to view and manage running changefeed jobs to roles that own the jobs or granting them the `VIEWJOB` or `CONTROLJOB` privilege. For more details, refer to View and manage changefeed jobs.
`CHANGEFEED` + `USAGE` on external connection	Create changefeeds on tables to an external connection URI. For details, refer to `CHANGEFEED` privilege. Deprecated: View and manage changefeed jobs on tables. Instead, transition users that need to view and manage running changefeed jobs to roles that own the jobs or granting them the `VIEWJOB` or `CONTROLJOB` privilege. For more details, refer to View and manage changefeed jobs. 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.
Job ownership	View and manage changefeed jobs (pause, resume, and cancel). For details, refer to View and manage changefeed jobs.
`CONTROLJOB`	Manage changefeed jobs (pause, resume, and cancel). For details, refer to View and manage changefeed jobs.
`VIEWJOB`	View changefeed jobs. For details, refer to View and manage changefeed jobs.
`SELECT`	Create a sinkless changefeed that emits messages to a SQL client.
Deprecated `CONTROLCHANGEFEED` 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 system-level privileges `CHANGEFEED` and `CONTROLJOB`/ `VIEWJOB` for fine-grained access control.
`admin`	Create, view, and manage changefeed jobs.

`CHANGEFEED` privilege

Viewing and managing changefeed jobs with the CHANGEFEED privilege is deprecated as of v25.1. Instead, transition users that need to view and manage running changefeed jobs to roles that own the jobs or granting them the VIEWJOB or CONTROLJOB privilege. For more details, refer to View and manage changefeed jobs.

You can grant 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 CONTROLCHANGEFEED role option or the SELECT privilege on the tables. 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 sink. You can add CHANGEFEED to the user or role’s default privileges with ALTER DEFAULT PRIVILEGES:

ALTER DEFAULT PRIVILEGES GRANT CHANGEFEED ON TABLES TO user;

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 CHANGEFEED privilege on a set of tables can only create changefeeds into external connections.

View and manage changefeed jobs

Users can view and manage changefeed jobs when one of the following are met:

Job ownership: They own the job, or are a member of a role that owns a job.
Global privileges: They are assigned CONTROLJOB or VIEWJOB.

To give a set of users access to a specific job, or set of jobs, assign them to a role that owns the job(s). You can transfer ownership of a job to a role or user using the ALTER JOB statement:

ALTER JOB job_ID OWNER TO role_name;

Synopsis

Parameters

Parameter	Description
`table_name`	The name of the table (or tables in a comma separated list) to create a changefeed for. Note: Before creating a changefeed, consider the number of changefeeds versus the number of tables to include in a single changefeed. Each scenario can have an impact on total memory usage or changefeed performance. Refer to Create and Configure Changefeeds for more detail.
`sink`	The location of the configurable sink. The scheme of the URI indicates the type. For more information, refer to Sink URI. Note: If you create a changefeed without a sink, your changefeed will run like a basic changefeed sending messages to the SQL client. For more detail, refer to the Create and Configure Changefeeds page.
`option` / `value`	For a list of available options and their values, refer to Options.

CDC query parameters

Change data capture queries allow you to define the change data emitted to your sink when you create a changefeed. See the Change Data Capture Queries page for detail on the functionality, syntax, and use cases for changefeeds created with queries.

Parameter	Description
`sink`	The location of the configurable sink. The scheme of the URI indicates the type. For more information, see Sink URI.
`option` / `value`	For a list of available options and their values, see Options.
`target_list`	The columns to emit data from.
`changefeed_target_expr`	The target table for the changefeed.
`opt_where_clause`	An optional `WHERE` clause to apply filters to the table.

Sink URI

To form the URI for each sink:

'{scheme}://{host}:{port}?{query_parameters}'

URI Component	Description
`scheme`	The type of sink, e.g., `kafka`, `gcpubsub`.
`host`	The sink’s hostname or IP address.
`port`	The sink’s port.
`query_parameters`	The sink’s query parameters.

For more comprehensive detail of using and configuring each sink, refer to:

Amazon MSK Amazon MSK
Apache Pulsar (in Preview) Apache Pulsar (in Preview)
Azure Event Hubs Azure Event Hubs
Cloud Storage / HTTP Cloud Storage / HTTP
Confluent Cloud Confluent Cloud
Google Cloud Pub/Sub Google Cloud Pub/Sub
Kafka Kafka
Webhook Webhook

You can create an external connection to represent a changefeed sink URI. This allows you to specify the external connection’s name in statements rather than the provider-specific URI. For detail on using external connections, see the CREATE EXTERNAL CONNECTION page.

Query parameters

Parameters should always be URI-encoded before they are included the changefeed’s URI, as they often contain special characters. Use Javascript’s encodeURIComponent function or Go language’s url.QueryEscape function to URI-encode the parameters. Other languages provide similar functions to URI-encode special characters.

Query parameters include:

Parameter	Sink Type	Type	Description
`ASSUME_ROLE`	Amazon S3, Google Cloud Storage, Google Cloud Pub/Sub	`STRING`	Pass the ARN of the role to assume. Use in combination with `AUTH=implicit` or `specified`. `external_id`: Use as a value to `ASSUME_ROLE` to specify the external ID for third-party access to your S3 bucket.
`AUTH`	Amazon S3, Google Cloud Storage, Google Cloud Pub/Sub, Azure Blob Storage	`STRING`	The authentication parameter can define either `specified` (default) or `implicit` authentication. To use `specified` authentication, pass your Service Account credentials with the URI. To use `implicit` authentication, configure these credentials via an environment variable. Refer to the Cloud Storage Authentication page page for examples of each of these.
`api_key`	Confluent Cloud	`STRING`	The API key created for the cluster in Confluent Cloud.
`api_secret`	Confluent Cloud	`STRING`	The API key’s secret generated in Confluent Cloud. Note: This must be URL-encoded before passing into the connection string.
`ca_cert`	Kafka, webhook, Confluent schema registry	`STRING`	The base64-encoded `ca_cert` file. Specify `ca_cert` for a Kafka sink, webhook sink, and/or a Confluent schema registry. For usage with a Kafka sink, see Kafka Sink URI. It’s necessary to state `https` in the schema registry’s address when passing `ca_cert`: `confluent_schema_registry='https://schema_registry:8081?ca_cert=LS0tLS1CRUdJTiBDRVJUSUZ'` See `confluent_schema_registry` for more detail on using this option. Note: To encode your `ca.cert`, run `base64 -w 0 ca.cert`.
`client_cert`	Kafka, webhook, Confluent schema registry	`STRING`	The base64-encoded Privacy Enhanced Mail (PEM) certificate. This is used with `client_key`.
`client_key`	Kafka, webhook, Confluent schema registry	`STRING`	The base64-encoded private key for the PEM certificate. This is used with `client_cert`. Note: Client keys are often encrypted. You will receive an error if you pass an encrypted client key in your changefeed statement. To decrypt the client key, run: `openssl rsa -in key.pem -out key.decrypt.pem -passin pass:{PASSWORD}`. Once decrypted, be sure to update your changefeed statement to use the new `key.decrypt.pem` file instead.
`file_size`	cloud	`STRING`	The file will be flushed (i.e., written to the sink) when it exceeds the specified file size. This can be used with the `WITH resolved` option, which flushes on a specified cadence. When you change or increase `file_size`, ensure that you adjust the `changefeed.memory.per_changefeed_limit` cluster setting, which has a default of `512MiB`. Buffering messages can quickly reach this limit if you have increased the file size. Refer to Advanced Changefeed Configuration for more detail. Default: `16MB`
`insecure_tls_skip_verify`	Kafka, webhook	`BOOL`	If `true`, disable client-side validation of responses. Note that a CA certificate is still required; this parameter means that the client will not verify the certificate. Warning: Use this query parameter with caution, as it creates MITM vulnerabilities unless combined with another method of authentication. Default: `false`
`partition_format`	cloud	`STRING`	Specify how changefeed file paths are partitioned in cloud storage sinks. Use `partition_format` with the following values: `daily` is the default behavior that organizes directories by dates (`2022-05-18/`, `2022-05-19/`, etc.). `hourly` will further organize directories by hour within each date directory (`2022-05-18/06`, `2022-05-18/07`, etc.). `flat` will not partition the files at all. For example: `CREATE CHANGEFEED FOR TABLE users INTO 'gs://...?AUTH...&partition_format=hourly'` Default: `daily`

For example: CREATE CHANGEFEED FOR TABLE users INTO 'gs://...?AUTH...&partition_format=hourly'

Default: daily S3_STORAGE_CLASS | Amazon S3 cloud storage sink | STRING | Specify the Amazon S3 storage class for files created by the changefeed. See Create a changefeed with an S3 storage class for the available classes and an example.

Default: STANDARD sasl_aws_iam_role_arn | Amazon MSK | STRING | The ARN for the IAM role that has the permissions to create a topic and send data to the topic. For more details on setting up an Amazon MSK cluster with an IAM role, refer to the AWS documentation. sasl_aws_iam_session_name | Amazon MSK | STRING | The user-specified string that identifies the session in AWS. sasl_aws_region | Amazon MSK | STRING | The region of the Amazon MSK cluster. sasl_client_id | Kafka | STRING | Client ID for OAuth authentication from a third-party provider. This parameter is only applicable with sasl_mechanism=OAUTHBEARER. sasl_client_secret | Kafka | STRING | Client secret for OAuth authentication from a third-party provider. This parameter is only applicable with sasl_mechanism=OAUTHBEARER. Note: You must base64 encode this value when passing it in as part of a sink URI. sasl_enabled | Amazon MSK, Azure Event Hubs, Kafka, Confluent Cloud | BOOL | If true, set the authentication protocol with the sasl_mechanism parameter. You must have tls_enabled set to true to use SASL.

For Confluent Cloud and Azure Event Hubs sinks, this is set to true by default.

Default: false sasl_grant_type | Kafka | STRING | Override the default OAuth client credentials grant type for other implementations. This parameter is only applicable with sasl_mechanism=OAUTHBEARER. sasl_handshake | Azure Event Hubs, Kafka, Confluent Cloud | BOOL | For Confluent Cloud and Azure Event Hubs sinks, this is set to true by default. sasl_mechanism | Amazon MSK, Azure Event Hubs, Kafka, Confluent Cloud | STRING | Can be set to OAUTHBEARER, SCRAM-SHA-256, SCRAM-SHA-512, or PLAIN. A sasl_user and sasl_password are required for PLAIN and SCRAM authentication.

For Amazon MSK clusters, set to AWS_MSK_IAM. sasl_aws_iam_role_arn, sasl_aws_iam_session_name, and sasl_aws_region are also required in the sink uri.

Refer to the Connect to a Changefeed Kafka sink with OAuth Using Okta tutorial for detail setting up OAuth using Okta.

For Confluent Cloud and Azure Event Hubs sinks, sasl_mechanism=PLAIN is required but set automatically by CockroachDB.

Default: PLAIN sasl_scopes | Kafka | STRING | A list of scopes that the OAuth token should have access for. This parameter is only applicable with sasl_mechanism=OAUTHBEARER. sasl_token_url | Kafka | STRING | Client token URL for OAuth authentication from a third-party provider. Note: You must URL encode this value before passing in a URI. This parameter is only applicable with sasl_mechanism=OAUTHBEARER. sasl_user | Amazon MSK, Kafka | STRING | Your SASL username. sasl_password | Amazon MSK, Kafka | STRING | Your SASL password. Note: Passwords should be URL encoded since the value can contain characters that would cause authentication to fail. shared_access_key | Azure Event Hubs | STRING | The URL-encoded key for your Event Hub shared access policy. shared_access_key_name | Azure Event Hubs | STRING | The name of your Event Hub shared access policy. tls_enabled | Amazon MSK, Kafka, Confluent Cloud | BOOL | If true, enable Transport Layer Security (TLS) on the connection to Kafka. This can be used with a ca_cert (see below).

For Confluent Cloud and Azure Event Hubs sinks, this is set to true by default.

Default: false topic_name | Azure Event Hubs, Kafka, Confluent Cloud, GC Pub/Sub | STRING | Allows arbitrary topic naming for Kafka and GC Pub/Sub topics. See the Kafka topic naming limitations or GC Pub/Sub topic naming for detail on supported characters etc.

For example, CREATE CHANGEFEED FOR foo,bar INTO 'kafka://sink?topic_name=all' will emit all records to a topic named all. Note that schemas will still be registered separately. When using Kafka, this parameter can be combined with the topic_prefix parameter (this is not supported for GC Pub/Sub).

Default: table name. topic_prefix | Azure Event Hubs, Kafka, Confluent Cloud | STRING | Adds a prefix to all topic names.

For example, CREATE CHANGEFEED FOR TABLE foo INTO 'kafka://...?topic_prefix=bar_' would emit rows under the topic bar_foo instead of foo.

Options

Option	Value	Description
`avro_mode`	`read` / `write`	Control how the changefeed interacts with the schema registry when using `format=avro`. This option is in Preview. `write`: Register the changefeed’s key and value schemas with the schema registry. `read`: Resolve the schema ID of an already-registered subject using GET requests only. The changefeed issues no registry writes. If no matching schema is registered, the changefeed encounters a retryable error and retries the lookup. Use `read` when the registry is managed out-of-band and the changefeed must not modify it. Use `avro_schemas` to override subject names and select registered schema versions, and `avro_resolved_subject` to emit `resolved` timestamps in `read` mode. Default: `avro_mode=write`
`avro_resolved_subject`	Schema Registry subject name	Store `resolved` timestamp schemas in a dedicated schema registry subject. With `avro_mode=read`, this option is required to use `resolved`, and the changefeed always selects the latest registered version of the subject. This option requires the `resolved` option. With `avro_mode=write`, if you omit this option, the changefeed registers resolved timestamp schemas under each topic’s value subject, including any `avro_schemas` override for that subject.
`avro_schema_prefix`	Schema prefix name	Provide a namespace for the schema of a table in addition to the default, the table name. This allows multiple databases or clusters to share the same schema registry when the same table name is present in multiple databases. Example: `CREATE CHANGEFEED FOR foo WITH format=avro, confluent_schema_registry='registry_url', avro_schema_prefix='super'` will register subjects as `superfoo-key` and `superfoo-value` with the namespace `super`.
`avro_schemas`	JSON object	Override schema registry subject names and select which registered schema version to use, keyed by default subject names. A default subject name is the table name, including any `avro_schema_prefix`, followed by `-key` or `-value`. Each key must match a table that the changefeed watches. Each entry can set `subject_name` and, with `avro_mode=read`, a `version`: `latest` (the default) uses the latest registered version and fails if it is incompatible, `latest_compatible` uses the newest compatible version, and `pin(<n>)` uses version `<n>`. Subject-name overrides also apply with `avro_mode=write`. If `avro_schemas` omits a `<table>-key` or `<table>-value` entry, the changefeed uses `<table>-key` or `<table>-value`, respectively, as the schema registry subject name in both read and write modes. In read mode, it fetches the latest schema version registered under that name. In write mode, it registers the generated schema under that name. Example: `avro_schemas='{"orders-value": {"subject_name": "acme.orders.v1", "version": "latest_compatible"}, "orders-key": {"subject_name": "acme.orders.key.v1"}}'`
`compression`	`gzip`, `zstd`	Compress changefeed data files written to: Cloud storage sinks Webhook sinks . For compression options when using a Kafka sink, see Kafka sink configuration.
`confluent_schema_registry`	Schema Registry address	The Schema Registry address is required to use `avro`. Use the `timeout={duration}` query parameter `timeout={duration}` query parameter (duration string) in your Confluent Schema Registry URI to change the default timeout for contacting the schema registry. By default, the timeout is 30 seconds. To connect to Confluent Cloud, use the following URL structure: `'https://{API_KEY_ID}:{API_SECRET_URL_ENCODED}@{CONFLUENT_REGISTRY_URL}:443'`. See the Stream a Changefeed to a Confluent Cloud Kafka Cluster tutorial for further detail. Use the `changefeed.schema_registry.retry_count` metric to measure the number of request retries performed when sending requests to the schema registry. For more detail on monitoring changefeeds, refer to Monitor and Debug Changefeeds.
`cursor`	Timestamp	Emit any changes after the given timestamp. `cursor` does not output the current state of the table first. When `cursor` is not specified, the changefeed starts by doing an initial scan of all the watched rows and emits the current value, then moves to emitting any changes that happen after the scan. The changefeed will encounter an error if you specify a timestamp that is before the configured garbage collection window for the target table. (Refer to `gc.ttlseconds`.) With default garbage collection settings, this means you cannot create a changefeed that starts more than the-default-MVCC-garbage-collection-interval in the past. You can use `cursor` to start-a-new-changefeed-where-a-previous-changefeed-ended. Example: `cursor='1536242855577149065.0000000000'`
`diff`	N/A	Publish a `before` field with each message, which includes the value of the row before the update was applied. Changefeeds must use the `diff` option with the default `wrapped` envelope or the `enriched` envelope to emit the `before` field.
`encode_json_value_null_as_object`	N/A	Emit JSON `NULL` values as `{"__crdb_json_null__": true}` to distinguish these values from SQL `NULL` values. Refer to the Changefeed Messages page for an example. Note: When this option is enabled, if the changefeed encounters the literal value `{"__crdb_json_null__": true}` in JSON, it will have the same representation as a JSON `NULL` value and a warning will be printed to the `DEV` logging channel.
`end_time`	Timestamp	Indicate the timestamp up to which the changefeed will emit all events and then complete with a `successful` status. Provide a future timestamp to `end_time` in number of nanoseconds since the Unix epoch. For example, `end_time="1655402400000000000"`. You cannot use `end_time` and `initial_scan = 'only'` simultaneously.
`envelope`	`wrapped` / `enriched` / `bare` / `key_only` / `row`	`wrapped` the default envelope structure for changefeed messages containing an array of the primary key, a top-level field for the type of message, and the current state of the row (or `null` for deleted rows). Refer to the Changefeed Message Envelopes page for more detail on each envelope. Default: `envelope=wrapped`. Default for CDC-queries: `envelope=bare`.
`execution_locality`	Key-value pairs	Restricts the execution of a changefeed to nodes that match the defined locality filter requirements, e.g., `WITH execution_locality = 'region=us-west-1a,cloud=aws'`. See Run a changefeed job by locality for usage and reference detail.
`extra_headers`	`json`	Specifies extra headers for webhook sinks and kafka sinks. Use this option to add headers to all messages sent to the sink. Example: `CREATE CHANGEFEED FOR foo WITH extra_headers='{"x-api-key": "xxx", "some-other-header": "yyy"}'`
`format`	`json` / `avro` / `csv` / `parquet` / `protobuf`	Format of the emitted message. `avro`: For mappings of CockroachDB types to Avro types, refer-to-the-table and detail on Avro-limitations. Note: `confluent_schema_registry` is required with `format=avro`. `csv`: You cannot combine `format=csv` with the `diff` or `resolved` options. Changefeeds use the same CSV format as the `EXPORT` statement. Refer to Export-data-with-changefeeds for details using these options to create a changefeed as an alternative to `EXPORT`. Note: `initial_scan = 'only'` is required with `format=csv`. `parquet`: Cloud storage is the only supported sink. The `topic_in_value` option is not compatible with `parquet` format. `protobuf`: Kafka and Cloud storage are the only supported sinks. The `headers_json_column_name` option is not compatible with `protobuf` format. Default: `format=json`.
`full_table_name`	N/A	Use fully qualified table name in topics, subjects, schemas, and record output instead of the default table name. This can prevent unintended behavior when the same table name is present in multiple databases. Note: This option cannot modify existing table names used as topics, subjects, etc., as part of an `ALTER CHANGEFEED` statement. To modify a topic, subject, etc., to use a fully qualified table name, create a new changefeed with this option. Example: `CREATE CHANGEFEED FOR foo... WITH full_table_name` will create the topic name `defaultdb.public.foo` instead of `foo`.
`gc_protect_expires_after`	Duration string	Automatically expires protected timestamp records that are older than the defined duration. In the case where a changefeed job remains paused, `gc_protect_expires_after` will trigger the underlying protected timestamp record to expire and cancel the changefeed job to prevent accumulation of protected data. Refer to Protect-Changefeed-Data-from-Garbage-Collection for more detail on protecting changefeed data.
`headers_json_column_name`	`STRING`	Specify a JSONB column that the changefeed emits as Kafka headers, separate from the message payload, for each row’s change event. `headers_json_column_name` is supported for Kafka sinks. For more details, refer to Specify a column as a Kafka header. Note: `headers_json_column_name` is not compatible with changefeeds running in `protobuf` format.
`ignore_disable_changefeed_replication`	`BOOL`	When set to `true`, the changefeed will emit events even if CDC filtering for TTL jobs is configured using the `disable_changefeed_replication` session variable, `sql.ttl.changefeed_replication.disabled` cluster setting, or the `ttl_disable_changefeed_replication` table storage parameter. Refer to Filter changefeeds for tables using TTL for usage details.
`initial_scan`	`yes`/`no`/`only`	Control whether or not an initial scan will occur at the start time of a changefeed. Only one `initial_scan` option (`yes`, `no`, or `only`) can be used. If none of these are set, an initial scan will occur if there is no `cursor`, and will not occur if there is one. This preserves the behavior from previous releases. With `initial_scan = 'only'` set, the changefeed job will end with a successful status (`succeeded`) after the initial scan completes. You cannot specify `yes`, `no`, `only` simultaneously. You cannot combine `initial_scan = 'only'` with the `diff`, `end_time`, `mvcc_timestamp`, `resolved`, or `updated` options. If used in conjunction with `cursor`, an initial scan will be performed at the cursor timestamp. If no `cursor` is specified, the initial scan is performed at `now()`. Although the `initial_scan` / `no_initial_scan` syntax from previous versions is still supported, you cannot combine the previous and current syntax. Default: `initial_scan = 'yes'`
`kafka_sink_config`	`STRING`	Set fields to configure the required level of message acknowledgement from the Kafka server, the version of the server, and batching parameters for Kafka sinks. Set the message file compression type. See Kafka sink configuration for more detail on configuring all the available fields for this option. Example: `CREATE CHANGEFEED FOR table INTO 'kafka://localhost:9092' WITH kafka_sink_config='{"Flush": {"MaxMessages": 1, "Frequency": "1s"}, "RequiredAcks": "ONE"}'`
`key_column`	`'column'`	Override the key used in message metadata. This changes the key hashed to determine downstream partitions. In sinks that support partitioning by message, CockroachDB uses the 32-bit FNV-1a hashing algorithm to determine which partition to send to. Note: `key_column` does not preserve ordering of messages from CockroachDB to the downstream sink, therefore you must also include the `unordered` option in your changefeed creation statement. It does not affect per-key ordering guarantees or the output of `key_in_value`. See the Define a key to determine the changefeed sink partition example.
`key_in_value`	N/A	Add a primary key array to the emitted message. This makes the primary key of a deleted row recoverable in sinks where each message has a value but not a key (most have a key and value in each message). `key_in_value` is automatically used for cloud storage sinks, webhook sinks, and GC Pub/Sub sinks.
`lagging_ranges_threshold`	Duration string	Set a duration from the present that determines the length of time a range is considered to be lagging behind, which will then track in the `lagging_ranges` metric. Note that ranges undergoing an initial scan for longer than the threshold duration are considered to be lagging. Starting a changefeed with an initial scan on a large table will likely increment the metric for each range in the table. As ranges complete the initial scan, the number of ranges lagging behind will decrease. Default: `3m`
`lagging_ranges_polling_interval`	Duration string	Set the interval rate for when lagging ranges are checked and the `lagging_ranges` metric is updated. Polling adds latency to the `lagging_ranges` metric being updated. For example, if a range falls behind by 3 minutes, the metric may not update until an additional minute afterward. Default: `1m`
`metrics_label`	`STRING`	Define a metrics label to which the metrics for one or multiple changefeeds increment. All changefeeds also have their metrics aggregated. The maximum length of a label is 128 bytes. There is a limit of 1024 unique labels. `WITH metrics_label=label_name` For more detail on usage and considerations, see Using changefeed metrics labels.
`min_checkpoint_frequency`	Duration string	Controls how often a node’s changefeed aggregator will flush their progress to the coordinating changefeed node. A node’s changefeed aggregator will wait at least the specified duration between sending progress updates for the ranges it is watching to the coordinator. This can help you control the flush frequency of higher latency sinks to achieve better throughput. However, more frequent checkpointing can increase CPU usage. If this is set to `0s`, a node will flush messages as long as the high-water mark has increased for the ranges that particular node is processing. If a changefeed is resumed, then `min_checkpoint_frequency` is the amount of time that changefeed will need to catch up. That is, it could emit duplicate messages during this time. Note: `resolved` messages will not be emitted more frequently than the configured `min_checkpoint_frequency` (but may be emitted less frequently). If you require `resolved` messages more frequently than `30s`, you must configure `min_checkpoint_frequency` to at least the desired `resolved` message frequency. For more details, refer to Resolved message frequency. Default: `30s`
`mvcc_timestamp`	N/A	Include the MVCC timestamp for each emitted row in a changefeed. With the `mvcc_timestamp` option, each emitted row will always contain its MVCC timestamp, even during the changefeed’s initial backfill.
`on_error`	`pause` / `fail`	Use `on_error=pause` to pause the changefeed when encountering non-retryable errors. `on_error=pause` will pause the changefeed instead of sending it into a terminal failure state. Note: Retryable errors will continue to be retried with this option specified. Use with `protect_data_from_gc_on_pause` to protect changes from garbage collection. If a changefeed with `on_error=pause` is running when a watched table is truncated, the changefeed will pause but will not be able to resume reads from that table. Using `ALTER CHANGEFEED` to drop the table from the changefeed and then resuming the job will work, but you cannot add the same table to the changefeed again. Instead, you will need to create a new changefeed for that table. Default: `on_error=fail`
`protect_data_from_gc_on_pause`	N/A	This option is deprecated as of v23.2 and will be removed in a future release. When a changefeed is paused, ensure that the data needed to resume the changefeed is not garbage collected. If `protect_data_from_gc_on_pause` is unset, pausing the changefeed will release the existing protected timestamp records. It is also important to note that pausing and adding `protect_data_from_gc_on_pause` to a changefeed will not protect data if the garbage collection window has already passed. Use with `on_error=pause` to protect changes from garbage collection when encountering non-retryable errors. Refer to Protect Changefeed Data from Garbage Collection for more detail on protecting changefeed data. Note: If you use this option, changefeeds that are left paused for long periods of time can prevent garbage collection. Use with the `gc_protect_expires_after` option to set a limit for protected data and for how long a changefeed will remain paused.
`pubsub_sink_config`	`STRING`	Set fields to configure sink batching and retries. The schema is as follows: `{ "Flush": { "Messages": ..., "Bytes": ..., "Frequency": ..., }, "Retry": {"Max": ..., "Backoff": ..., } }`. Note that if either `Messages` or `Bytes` are nonzero, then a non-zero value for `Frequency` must be provided. Refer to Pub/Sub sink configuration for more details on using this option.
`resolved`	Duration string	Emit resolved timestamps in a format dependent on the connected sink. Resolved timestamps do not emit until the changefeed job’s progress has been checkpointed. Set a minimum amount of time that the changefeed’s high-water mark (overall resolved timestamp) must advance by before another resolved timestamp is emitted. Example: `resolved='10s'`. This option will only emit a resolved timestamp if the timestamp has advanced (and by at least the optional duration, if set). If a duration is unspecified, all resolved timestamps are emitted as the high-water mark advances. Note: If you set `resolved` lower than `30s`, then you must also set `min_checkpoint_frequency` to at minimum the same value as `resolved`, because `resolved` messages may be emitted less frequently than `min_checkpoint_frequency`, but cannot be emitted more frequently. Refer to Resolved messages for more detail. Note: With `format=avro` and `avro_mode=read`, `resolved` requires the `avro_resolved_subject` option.
`schema_change_events`	`default` / `column_changes`	The type of schema change event that triggers the behavior specified by the `schema_change_policy` option: `default`: Include all `ADD COLUMN` events for columns that have a non-`NULL` `DEFAULT` value or are computed, and all `DROP COLUMN` events. `column_changes`: Include all schema change events that add or remove any column. Default: `schema_change_events=default`
`schema_change_policy`	`backfill` / `nobackfill` / `stop`	The behavior to take when an event specified by the `schema_change_events` option occurs: `backfill`: When schema changes with column backfill are finished, output all watched rows using the new schema. `nobackfill`: For schema changes with column backfill, perform no logical backfills. The changefeed will not emit any messages about the schema change. However, if the schema change with column backfill runs inside an explicit transaction and the `autocommit_before_ddl` session setting is disabled, it will emit the entire table to the changefeed. `stop`: For schema changes with column backfill, wait for all data preceding the schema change to be resolved before exiting with an error indicating the timestamp at which the schema change occurred. An `error: schema change occurred at <timestamp>` will display in the `cockroach.log` file. Default: `schema_change_policy=backfill`
`split_column_families`	N/A	Use this option to create a changefeed on a table with multiple column families. The changefeed will emit messages for each of the table’s column families. See Changefeeds on tables with column families for more usage detail.
`topic_in_value`	`BOOL`	Set to include the topic in each emitted row update. This option is automatically set for webhook sinks. Note: `topic_in_value` is not compatible with changefeeds running in `parquet` format.
`unordered`	N/A	Run a changefeed to Google Cloud Pub/Sub without specifying a region. You must include the `unordered` option with `key_column` in your changefeed creation statement. You cannot use `unordered` with `resolved`, because resolved timestamps may not be correct in unordered mode.
`updated`	N/A	Include updated timestamps with each row. If a `cursor` is provided, the “updated” timestamps will match the MVCC timestamps of the emitted rows, and there is no initial scan. If a `cursor` is not provided, the changefeed will perform an initial scan (as of the time the changefeed was created), and the “updated” timestamp for each change record emitted in the initial scan will be the timestamp of the initial scan. Similarly, when a backfill is performed for a schema change, the “updated” timestamp is set to the first timestamp for when the new schema is valid.
`virtual_columns`	`STRING`	Changefeeds omit virtual computed columns from emitted messages by default. To maintain the behavior of previous CockroachDB versions where the changefeed would emit `NULL` values for virtual computed columns, set `virtual_columns = "null"` when you start a changefeed. You may also define `virtual_columns = "omitted"`, though this is already the default behavior for v22.1+. If you do not set `"omitted"` on a table with virtual computed columns when you create a changefeed, you will receive a warning that changefeeds will filter out virtual computed values. Default: `"omitted"`
`webhook_auth_header`	`STRING`	Pass a value (password, token etc.) to the HTTP Authorization header with a webhook request for a “Basic” HTTP authentication scheme. Example: With a username of “user” and password of “pwd”, add a colon between “user:pwd” and then base64 encode, which results in “dXNlcjpwd2Q=”. `WITH webhook_auth_header='Basic dXNlcjpwd2Q='`.
`webhook_client_timeout`	`INTERVAL`	If a response is not recorded from the sink within this timeframe, it will error and retry to connect. Note this must be a positive value. Default: `"3s"`
`webhook_sink_config`	`STRING`	Set fields to configure sink batching and retries. The schema is as follows: `{ "Flush": { "Messages": ..., "Bytes": ..., "Frequency": ..., }, "Retry": {"Max": ..., "Backoff": ..., } }`. Note that if either `Messages` or `Bytes` are nonzero, then a non-zero value for `Frequency` must be provided. See Webhook sink configuration for more details on using this option.

Using the format=avro, envelope=key_only, and updated options together is rejected. envelope=key_only prevents any rows with updated fields from being emitted, which makes the updated option meaningless.

Files

The files emitted to a sink use the following naming conventions:

General file format
Resolved file format

The timestamp format is YYYYMMDDHHMMSSNNNNNNNNNLLLLLLLLLL.

General file format

/[date]/[timestamp]-[uniquer]-[topic]-[schema-id]

For example:

/2020-04-02/202004022058072107140000000000000-56087568dba1e6b8-1-72-00000000-test_table-1.ndjson

When emitting changefeed messages to a cloud storage sink, you can specify a partition format for your files using the partition_format query parameter. This will result in the following file path formats:

daily: This is the default option and will follow the same pattern as the previous general file format.
hourly: This will partition into an hourly directory as the changefeed emits messages, like the following:
/2020-04-02/20/202004022058072107140000000000000-56087568dba1e6b8-1-72-00000000-test_table-1.ndjson
flat: This will result in no file partitioning. The cloud storage path you specify when creating a changefeed will store all of the message files with no additional directories created.

Resolved file format

/[date]/[timestamp].RESOLVED

For example:

/2020-04-04/202004042351304139680000000000000.RESOLVED

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 following examples show the syntax for managing changefeeds and starting changefeeds with different use cases and features. The Options table on this page provides a list of all the available options. For information on sink-specific query parameters and configurations, refer to the Changefeed Sinks page. You can create an external connection to represent a changefeed sink URI. This allows you to specify the external connection’s name in statements rather than the provider-specific URI. For detail on using external connections, see the CREATE EXTERNAL CONNECTION page. We recommend limiting the number of changefeeds per cluster to 80.

Create a changefeed connected to a sink

CREATE CHANGEFEED FOR TABLE table_name, table_name2, table_name3
  INTO 'scheme://host:port'
  WITH updated, resolved;

You can connect a changefeed to the following sinks:

Amazon MSK Amazon MSK
Apache Pulsar (in Preview) Apache Pulsar (in Preview)
Azure Event Hubs Azure Event Hubs
Cloud Storage / HTTP Cloud Storage / HTTP
Confluent Cloud Confluent Cloud
Google Cloud Pub/Sub Google Cloud Pub/Sub
Kafka Kafka
Webhook Webhook

Create a changefeed that filters and transforms change data

CDC queries can filter and transform change data before emitting it to a sink or a SQL client. You can adapt a changefeed with CDC queries by including SELECT and WHERE clauses in your CREATE statement:

CREATE CHANGEFEED INTO 'scheme://host:port'
  WITH updated, resolved
  AS SELECT owner_id, status
  FROM vehicles
  WHERE status = 'lost';

CDC queries can only run on a single table per changefeed.

Create a sinkless changefeed

You can create a changefeed that will send messages to the SQL client rather than a sink:

CREATE CHANGEFEED FOR TABLE table_name, table_name2, table_name3
  WITH updated, resolved;

To create a sinkless changefeed using CDC queries:

CREATE CHANGEFEED WITH updated, resolved
  AS SELECT owner_id, status
  FROM vehicles
  WHERE status = 'lost';

Use an external connection to specify a changefeed sink

External connections provide a way to define a name for a sink, which you can use instead of the provider-specific URI. 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 CHANGEFEED privilege on a set of tables can only create changefeeds into external connections. External connections support all changefeed sinks.

CREATE EXTERNAL CONNECTION kafka_sink
  AS 'kafka://broker.address.com:9092?topic_prefix=bar_&tls_enabled=true&ca_cert={certificate}&sasl_enabled=true&sasl_user={sasl user}&sasl_password={url-encoded password}&sasl_mechanism=SCRAM-SHA-256';

In the changefeed statement, you specify the external connection name:

CREATE CHANGEFEED FOR TABLE table_name INTO 'external://kafka_sink'
  WITH resolved;

Filter changefeeds for tables using row-level TTL

Use the ttl_disable_changefeed_replication table storage parameter to prevent changefeeds from sending DELETE messages issued by row-level TTL jobs for a table. Include the storage parameter when you create or alter the table. For example:

CREATE TABLE tbl (
  id UUID PRIMARY KEY default gen_random_uuid(),
  value TEXT
) WITH (ttl_expire_after = '3 weeks', ttl_job_cron = '@daily', ttl_disable_changefeed_replication = 'true');

ALTER TABLE events SET (ttl_expire_after = '1 year', ttl_disable_changefeed_replication = 'true');

You can also widen the scope to the cluster by setting the sql.ttl.changefeed_replication.disabled cluster setting to true. This will prevent changefeeds from emitting deletes issued by all TTL jobs on a cluster. If you want to have a changefeed ignore the storage parameter or cluster setting that disables changefeed replication, you can set the changefeed option ignore_disable_changefeed_replication to true:

CREATE CHANGEFEED FOR TABLE table_name INTO 'external://changefeed-sink'
  WITH resolved, ignore_disable_changefeed_replication = true;

This is useful when you have multiple use cases for different changefeeds on the same table. For example, you have a table with a changefeed streaming changes to another database for analytics workflows in which you do not want to reflect row-level TTL deletes. Secondly, you have a changefeed on the same table for audit-logging purposes for which you need to persist every change through the changefeed. For guidance on how to filter changefeed messages to emit row-level TTL deletes only, refer to Change Data Capture Queries.

Disallow schema changes on tables to improve changefeed performance

Use the schema_locked storage parameter to indicate that a schema change is not currently ongoing on a watched table. This allows the changefeed to take a fast path that avoids checking if there are schema changes that could require synchronization between changefeed aggregators. This helps to decrease the latency between a write committing to a table and it emitting to the changefeed’s sink. Enable schema_locked on the watched table with the ALTER TABLE statement:

ALTER TABLE watched_table SET (schema_locked = true);

By default, CockroachDB attempts to automatically unset schema_locked before performing many schema changes and reapplies it when done. To require manual unlocks for all DDL on schema-locked tables, set sql.schema.auto_unlock.enabled to false. Some schema changes, such as ALTER TABLE ... SET LOCALITY, cannot automatically unset schema_locked even when automatic unlocking is enabled. For these cases, you must manually unlock the table with schema_locked = false, complete the schema change, and then lock the table again with schema_locked = true. The changefeed will run as normal while schema_locked is unset, but it will not benefit from the performance optimization.

ALTER TABLE watched_table SET (schema_locked = false);

Manage a changefeed

For changefeed jobs, use SHOW CHANGEFEED JOBS to check the status:

SHOW CHANGEFEED JOBS;

Use the following SQL statements to pause, resume, or cancel a changefeed.

Pause a changefeed

PAUSE JOB job_id;

For more information, see PAUSE JOB.

Resume a paused changefeed

RESUME JOB job_id;

For more information, see RESUME JOB.

Cancel a changefeed

CANCEL JOB job_id;

For more information, see CANCEL JOB.

Modify a changefeed

To modify a changefeed, pause the job and then use:

ALTER CHANGEFEED job_id {ADD table DROP table SET option UNSET option};

You can add new table targets, remove them, set new changefeed options, and unset them. For more information, see ALTER CHANGEFEED.

Configuring all changefeeds

It is useful to be able to pause all running changefeeds during troubleshooting, testing, or when a decrease in CPU load is needed. To pause all running changefeeds:

PAUSE JOBS (WITH x AS (SHOW CHANGEFEED JOBS) SELECT job_id FROM x WHERE status = ('running'));

This will change the status for each of the running changefeeds to paused, which can be verified with SHOW CHANGEFEED JOBS. To resume all running changefeeds:

RESUME JOBS (WITH x AS (SHOW CHANGEFEED JOBS) SELECT job_id FROM x WHERE status = ('paused'));

This will resume the changefeeds and update the status for each of the changefeeds to running.

Start a new changefeed where another ended

In some situations, you may want to start a changefeed where a previously running changefeed ended. For example, a changefeed could encounter an error it cannot recover from, such as when a TRUNCATE is performed, and you need to restart the changefeed.

Use SHOW CHANGEFEED JOB to find the high-water timestamp for the ended changefeed:

SHOW CHANGEFEED JOB {job_id};

        job_id       | ... |      high_water_timestamp      | ...
+--------------------+ ... +--------------------------------+ ...
  383870400694353921 | ... | 1537279405671006870.0000000000 | ...
(1 row)

If a changefeed has failed, you must restart the changefeed from a timestamp after the event that caused the failure.

Use the high_water_timestamp to start the new changefeed:

CREATE CHANGEFEED FOR TABLE table_name, table_name2, table_name3
  INTO 'scheme//host:port'
  WITH cursor = '<high_water_timestamp';

When you use the cursor option to start a changefeed, it will not perform an initial scan.

Create a changefeed with an S3 storage class

To associate the changefeed message files with a specific storage class in your Amazon S3 bucket, use the S3_STORAGE_CLASS parameter with the class. For example, the following S3 connection URI specifies the INTELLIGENT_TIERING storage class:

CREATE CHANGEFEED FOR TABLE table_name
  INTO 's3://{BUCKET NAME}?AWS_ACCESS_KEY_ID={KEY ID}&AWS_SECRET_ACCESS_KEY={SECRET ACCESS KEY}&S3_STORAGE_CLASS=INTELLIGENT_TIERING'
  WITH resolved;

Use the parameter to set one of these storage classes listed in Amazon’s documentation. For more general usage information, see Amazon’s Using Amazon S3 storage classes documentation.

Define a key to determine the changefeed sink partition

With the key_column option, you can define the key used in message metadata that determines the partition for the changefeed message at your downstream sink. This option overrides the default primary key:

CREATE CHANGEFEED FOR TABLE table_name
  INTO 'external://kafka-sink'
  WITH key_column='partition_column', unordered;

key_column does not preserve ordering of messages from CockroachDB to the downstream sink, therefore you must include the unordered option. It does not affect per-key ordering guarantees or the output of key_in_value.

Statements

Syntax

Data Types

Spatial Data

Constraints

Required privileges

Privilege model

`CHANGEFEED` privilege

View and manage changefeed jobs

Synopsis

Parameters

CDC query parameters

Sink URI

Query parameters

Options

Files

General file format

Resolved file format

Examples

Create a changefeed connected to a sink

Create a changefeed that filters and transforms change data

Create a sinkless changefeed

Use an external connection to specify a changefeed sink

Filter changefeeds for tables using row-level TTL

Disallow schema changes on tables to improve changefeed performance

Manage a changefeed

Pause a changefeed

Resume a paused changefeed

Cancel a changefeed

Modify a changefeed

Configuring all changefeeds

Start a new changefeed where another ended

Create a changefeed with an S3 storage class

Define a key to determine the changefeed sink partition

See also

​Required privileges

​Privilege model

​CHANGEFEED privilege

​View and manage changefeed jobs

​Synopsis

​Parameters

​CDC query parameters

​Sink URI

​Query parameters

​Options

​Files

​General file format

​Resolved file format

​Examples

​Create a changefeed connected to a sink

​Create a changefeed that filters and transforms change data

​Create a sinkless changefeed

​Use an external connection to specify a changefeed sink

​Filter changefeeds for tables using row-level TTL

​Disallow schema changes on tables to improve changefeed performance

​Manage a changefeed

​Pause a changefeed

​Resume a paused changefeed

​Cancel a changefeed

​Modify a changefeed

​Configuring all changefeeds

​Start a new changefeed where another ended

​Create a changefeed with an S3 storage class

​Define a key to determine the changefeed sink partition

​See also

Required privileges

Privilege model

`CHANGEFEED` privilege

View and manage changefeed jobs

Synopsis

Parameters

CDC query parameters

Sink URI

Query parameters

Options

Files

General file format

Resolved file format

Examples

Create a changefeed connected to a sink

Create a changefeed that filters and transforms change data

Create a sinkless changefeed

Use an external connection to specify a changefeed sink

Filter changefeeds for tables using row-level TTL

Disallow schema changes on tables to improve changefeed performance

Manage a changefeed

Pause a changefeed

Resume a paused changefeed

Cancel a changefeed

Modify a changefeed

Configuring all changefeeds

Start a new changefeed where another ended

Create a changefeed with an S3 storage class

Define a key to determine the changefeed sink partition

See also