YDB change data capture and delivery to YDS

A Data Streams stream can get data from Managed Service for YDB databases in real time using the Change Data Capture (CDC) technology.

To set up CDC using Data Transfer:

1. Prepare the Managed Service for YDB source database.
2. Create a target stream in Data Streams.
3. Set up and activate the transfer.
4. Test your transfer.

If you no longer need the resources you created, delete them.

Required paid resourcesRequired paid resources

• Managed Service for YDB databases (see Managed Service for YDB pricing). The cost depends on deployment mode:

  • In serverless mode, you pay for data operations and storage volume, including stored backups.
  • In dedicated instance mode, you pay for the use of computing resources allocated to the database, storage size, and backups.

• Data Streams (see Data Streams pricing). The cost depends on the pricing model:

  • Based on allocated resources: You pay a fixed hourly rate for the established throughput limit and message retention period, and additionally for the number of units of actually written data.
  • On-demand: You pay for the performed read/write operations, the amount of read or written data, and the actual storage used for messages that are still within their retention period.

Getting startedGetting started

Set up the infrastructure:

Prepare the Managed Service for YDB source databasePrepare the Managed Service for YDB source database

1. Get ready for running SQL queries in the Managed Service for YDB source database:

   Management console

   YDB CLI

   1. In the management console, select the folder containing your database.
   2. From the list of services, select Managed Service for YDB.
   3. Select the database from the list and go to the Navigation tab.
   4. Click New SQL query.

   1. Set up a connection to the Managed Service for YDB database.

   2. Make sure you can run queries using the YDB CLI with the selected authentication mode. For example, for an OAuth token, run the following query:

      ydb \
        --endpoint <endpoint> \
        --database <DB_name> \
        --yc-token-file <path_to_OAuth_token> \
        yql -s "SELECT 1;"
      

      Result:

      ┌─────────┐
      | column0 |
      ├─────────┤
      | 1       |
      └─────────┘
      

2. Create a table for test data:

   CREATE TABLE test
   (
       id Uint64,
       text Utf8,
       PRIMARY KEY (id)
   );
   

Create a target stream in Data StreamsCreate a target stream in Data Streams

Create a stream for the Data Streams.

Set up and activate the transferSet up and activate the transfer

1. Create an YDB source endpoint:

   • Connection settings:

     • Database: Select the Managed Service for YDB database from the list.
     • Service account ID: Select an existing service account or create a new one with the ydb.editor role.

   • Included paths list:

     • Path 1: test.

2. Create an endpoint for the Yandex Data Streams target:

   • Connection settings:

     • Database: Select the Managed Service for YDB database for the target stream from the list.
     • Stream: Specify the name of the stream in Data Streams.
     • Service account: Select an existing service account or create a new one with the yds.editor role.

   • Serializing settings: Auto.

3. Create a transfer:

   Manually

   Terraform

   1. Create a Replication-type transfer configured to use the new endpoints.
   2. Activate the transfer.

   1. In the data-transfer-ydb-yds.tf file, specify the following variables:

      • source_endpoint_id: ID of the source endpoint.
      • target_endpoint_id: ID of the target endpoint.
      • transfer_enabled: 1 to create a transfer.

   2. Validate your Terraform configuration files using this command:

      terraform validate
      

      Terraform will display any configuration errors detected in your files.

   3. Create the required infrastructure:

      1. Run this command to view the planned changes:

         terraform plan
         

         If you described the configuration correctly, the terminal will display a list of the resources to update and their parameters. This is a verification step that does not apply changes to your resources.

      2. If everything looks correct, apply the changes:

         1. Run this command:

            terraform apply
            

         2. Confirm updating the resources.

         3. Wait for the operation to complete.

      The transfer will activate automatically upon creation.

Test the transferTest the transfer

1. Wait for the transfer status to change to Replicating.

2. Add the test data to the test table in the Managed Service for YDB source database:

   INSERT INTO test
   (
       id,
       text
   )
   VALUES
   (
       1,
       'text 1'
   ),
   (
       2,
       'text 2'
   ),
   (
       3,
       'text 3'
   );
   

Make sure the data from the source has been moved to the Data Streams stream:

Delete the resources you createdDelete the resources you created

To reduce the consumption of resources you do not need, delete them:

1. Delete the transfer.

2. Delete the source and target endpoints.

3. If you created service accounts together with the endpoints, delete them.

4. Delete other resources using the same method used for their creation:

   Manually

   Terraform

   1. Delete the Managed Service for YDB source database.
   2. Delete the Managed Service for YDB database used for the target stream.

   1. In the terminal window, go to the directory containing the infrastructure plan.

      Warning

      Make sure the directory has no Terraform manifests with the resources you want to keep. Terraform deletes all resources that were created using the manifests in the current directory.

   2. Delete resources:

      1. Run this command:

         terraform destroy
         

      2. Confirm deleting the resources and wait for the operation to complete.

      All the resources described in the Terraform manifests will be deleted.