Contact UsGet started
© 2025 Direct Cursus Technology L.L.C.

Migrating databases from Greenplum® to ClickHouse®

Written by
Updated at December 5, 2025

You can migrate a database from Greenplum® to ClickHouse® using Yandex Data Transfer.

To transfer a database from Greenplum® to ClickHouse®:

  1. Set up your transfer.
  2. Activate the transfer.
  3. Verify replication after reactivation.

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

The support cost for this solution includes:

Getting started

In our example, we will create all required resources in Yandex Cloud. Set up the infrastructure:

  1. Create a Greenplum® source cluster in Yandex MPP Analytics for PostgreSQL with any suitable configuration.

  2. Create a Yandex Managed Service for ClickHouse® target cluster with a database named db1 using any suitable configuration.

  3. If using security groups, make sure they are configured correctly and allow inbound connections to the clusters.

  4. Create a ClickHouse® target endpoint. In the endpoint settings, specify Drop or Truncate as the cleanup policy to prevent duplication of copied data.

  1. If you do not have Terraform yet, install it.

  2. Get the authentication credentials. You can add them to environment variables or specify them later in the provider configuration file.

  3. Configure and initialize a provider. There is no need to create a provider configuration file manually, you can download it.

  4. Place the configuration file in a separate working directory and specify the parameter values. If you did not add the authentication credentials to environment variables, specify them in the configuration file.

  5. Download the greenplum-clickhouse.tf configuration file to your current working directory.

    This file describes:

    • Networks and subnets where your clusters will be hosted.

    • Security groups for cluster access.

    • Greenplum® source cluster in Yandex MPP Analytics for PostgreSQL.

    • Managed Service for ClickHouse® target cluster.

    • Target endpoint.

  6. Specify the following in greenplum-clickhouse.tf:

    • mgp_password: Greenplum® admin password.
    • mch_db: ClickHouse® database name.
    • mch_user: ClickHouse® database user name.
    • mch_password: ClickHouse® database user password.

  7. Make sure the Terraform configuration files are correct using this command:

    terraform validate

    Terraform will show any errors found in your configuration files.

  8. 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.

    All the required resources will be created in the specified folder. You can check resource availability and their settings in the management console.

Set up your transfer

  1. Create a Greenplum® source endpoint and specify its cluster connection settings.

  2. Create a Snapshot transfer that uses endpoints for the source and target.

    While real-time replication is not supported for this endpoint pair, you can configure regular copying while creating the transfer. To do this, in the Transfer parameters field under Snapshot, select Regular and specify the copy interval. The transfer will automatically activate after the specified interval.

Activate the transfer

  1. Connect to the Greenplum® cluster, create a table named x_tab, and populate it with data:

    CREATE TABLE x_tab
(
    id NUMERIC,
    name CHARACTER(5)
);
CREATE INDEX ON x_tab (id);
INSERT INTO x_tab (id, name) VALUES
(40, 'User1'),
(41, 'User2'),
(42, 'User3'),
(43, 'User4'),
(44, 'User5');

  2. Activate the transfer and wait for its status to change to Completed.

  3. To verify the data transfer, connect to the Managed Service for ClickHouse® target cluster and check whether the columns of the x_tab table in the db1 database match those of the x_tab table in the source database:

    SELECT id, name FROM db1.x_tab;

    ┌─id─┬─name──┐
│ 40 │ User1 │
│ 41 │ User2 │
│ 42 │ User3 │
│ 43 │ User4 │
│ 44 │ User5 │
└────┴───────┘

Verify replication after reactivation

  1. Connect to the Greenplum® cluster. Then, in the x_tab table, delete one row and update another:

    DELETE FROM x_tab WHERE id = 41;
UPDATE x_tab SET name = 'Key3' WHERE id = 42;

  2. Reactivate the transfer and wait for its status to change to Completed.

  3. Make sure the changes have been applied to the x_tab table on the ClickHouse® target:

    SELECT id, name FROM db1.x_tab;

    ┌─id─┬─name──┐
│ 42 │ Key3  │
│ 40 │ User1 │
│ 43 │ User4 │
│ 44 │ User5 │
└────┴───────┘

Delete the resources you created

Some resources are not free of charge. Delete the resources you no longer need to avoid paying for them:

  1. Make sure the transfer status is Completed, upon which you can delete the transfer.

  2. Delete the source endpoint.

  3. Delete the other resources depending on how you created them:

    1. Delete the Managed Service for ClickHouse® cluster.
    2. Delete the Greenplum® cluster.
    3. Delete the target endpoint.

    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.

ClickHouse® is a registered trademark of ClickHouse, Inc.

Previous
Fixing string sorting issues in PostgreSQL after upgrading glibc
Next
Migrating a database from Greenplum® to PostgreSQL