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Migrating data from Managed Service for PostgreSQL to Managed Service for MySQL® using Data Transfer

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Updated at December 24, 2024

You can set up data transfer from Managed Service for PostgreSQL to Managed Service for MySQL® databases using Data Transfer. To do this:

  1. Prepare the test data.
  2. Prepare and activate the transfer.
  3. Test the transfer.

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

Getting started

Prepare the infrastructure:

  1. Create a Managed Service for PostgreSQL source cluster in any availability zone with publicly available hosts in any suitable configuration with the following settings:

    • DB name: mpg_db.
    • Username: mpg_user.
    • Password: <source_password>.

  2. Grant the mdb_replication role to mpg_user.

  3. In the same availability zone, create a Managed Service for MySQL® target cluster with publicly available hosts in any suitable configuration and the following settings:

    • DB name: mmy_db.
    • Username: mmy_user.
    • Password: <target_password>.

  4. Make sure that the cluster security groups are set up correctly and allow connecting to them:

  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 postgresql-mysql.tf configuration file to the same working directory.

    This file describes:

    • Networks and subnets for hosting the clusters.
    • Security groups for making cluster connections.
    • Managed Service for PostgreSQL source cluster.
    • Managed Service for MySQL® target cluster.
    • Source and target endpoints.
    • Transfer.

  6. Specify the following in the postgresql-mysql.tf file:

    • MySQL® and PostgreSQL versions
    • MySQL® and PostgreSQL user passwords

  7. Check that the Terraform configuration files are correct using this command:

    terraform validate

    If there are any errors in the configuration files, Terraform will point them out.

  8. Create the required infrastructure:

    1. Run the command to view planned changes:

      terraform plan

      If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.

    2. If you are happy with the planned changes, apply them:

      1. Run the command:

        terraform apply

      2. Confirm the update of 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.

Prepare the test data

  1. Connect to the Managed Service for PostgreSQL source cluster database.

  2. Add test data to the database. As an example, we will use a simple table with information transmitted by car sensors.

    Create a table:

    CREATE TABLE measurements (
    device_id varchar(200) NOT NULL,
    datetime timestamp NOT NULL,
    latitude real NOT NULL,
    longitude real NOT NULL,
    altitude real NOT NULL,
    speed real NOT NULL,
    battery_voltage real,
    cabin_temperature real NOT NULL,
    fuel_level real,
    PRIMARY KEY (device_id)
);

    Populate the table with data:

    INSERT INTO measurements VALUES
('iv9a94th6rzt********', '2022-06-05 17:27:00', 55.70329032, 37.65472196,  427.5,    0, 23.5, 17, NULL),
('rhibbh3y08qm********', '2022-06-06 09:49:54', 55.71294467, 37.66542005, 429.13, 55.5, NULL, 18, 32);

Prepare and activate the transfer

  1. Create a source endpoint of the PostgreSQL type and specify the cluster connection parameters in it:

    • Installation type: Managed Service for PostgreSQL cluster.
    • Managed Service for PostgreSQL cluster: <PostgreSQL_source_cluster_name> from the drop-down list.
    • Database: mpg_db.
    • User: mpg_user.
    • Password: <user_password>.

  2. Create a target endpoint of the MySQL® type and specify the cluster connection parameters in it:

    • Connection type: Managed Service for MySQL cluster.
    • Managed Service for MySQL cluster: <MySQL®_target_cluster_name> from the drop-down list.
    • Database: mmy_db.
    • User: mmy_user.
    • Password: <user_password>.

  3. Create a transfer of the Snapshot and replication type that will use the created endpoints.

  4. Activate the transfer and wait for its status to change to Replicating.

  1. In the postgresql-mysql.tf file, set the transfer_enabled parameter to 1.

  2. Check that the Terraform configuration files are correct using this command:

    terraform validate

    If there are any errors in the configuration files, Terraform will point them out.

  3. Create the required infrastructure:

    1. Run the command to view planned changes:

      terraform plan

      If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.

    2. If you are happy with the planned changes, apply them:

      1. Run the command:

        terraform apply

      2. Confirm the update of resources.

      3. Wait for the operation to complete.

  4. The transfer will be activated automatically. Wait for its status to change to Replicating.

Note

If the transfer activation fails with the Unable to push DDL error:

  1. Connect to the target database and create an empty table named measurements similar to the one in the source.
  2. Restart the transfer.

Test the transfer

Check the transfer performance by testing the copy and replication processes.

Test the copy process

  1. Connect to the Managed Service for MySQL® target cluster database.

  2. Make sure the source table has been transferred to the target database. For this, run the following query:

    SELECT * FROM measurements;

Test the replication process

  1. Connect to the Managed Service for PostgreSQL source cluster database.

  2. Populate the measurements table with data:

    INSERT INTO measurements VALUES
('iv7b74th678t********', '2020-06-08 17:45:00', 53.70987913, 36.62549834, 378.0, 20.5, 5.3, 20, NULL);

  3. Make sure the new row has been added to the target database:

    1. Connect to the Managed Service for MySQL® target cluster database.

    2. Run the following query:

      SELECT * FROM measurements;

Delete the resources you created

Note

Before deleting the created resources, deactivate the transfer.

Some resources are not free of charge. To avoid paying for them, delete the resources you no longer need:

  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.

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