Loading data from Yandex Object Storage to a ClickHouse® data mart

You can migrate data from Yandex Object Storage to the Managed Service for ClickHouse® table using Data Transfer. Proceed as follows:

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

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

Required paid resourcesRequired paid resources

• Object Storage bucket: Use of storage, data operations (see Object Storage pricing).
• Managed Service for ClickHouse® cluster: Computing resources allocated to hosts, storage and backup size (see Managed Service for ClickHouse® pricing).
• Public IP addresses if public access is enabled for cluster hosts (see Virtual Private Cloud pricing).

Getting startedGetting started

Set up the infrastructure:

Prepare your test dataPrepare your test data

1. Prepare two CSV files with test data:

   • demo_data1.csv:

     1,Anna
     2,Robert
     3,Umar
     4,Algul
     5,Viktor
     

   • demo_data2.csv:

     6,Maria
     7,Alex
     

2. Upload the demo_data1.csv file to the Object Storage bucket.

Set up and activate the transferSet up and activate the transfer

1. Create an Object Storage-type source endpoint with the following settings:

   • Database type: Object Storage.

   • Bucket: Object Storage bucket name.

   • Access Key ID: Public part of the service account static key. If you created your infrastructure using Terraform, copy the key value from the Yandex Lockbox secret.

   • Secret Access Key: Private part of the service account’s static key. If you created your infrastructure using Terraform, copy the key value from the Yandex Lockbox secret.

   • Endpoint: https://storage.yandexcloud.net.

   • Region: ru-central1.

   • Data format: CSV.

   • Delimiter: Comma (,).

   • Table: table1.

   • Result table schema: Select Manual and specify the following field names and data types:

     • Id: Int64
     • Name: UTF8

   Keep the default values for all other settings.

2. Create a target endpoint and set up the transfer:

   Manually

   Using Terraform

   1. Create the ClickHouse®-type target endpoint and specify its cluster connection settings:

      • Connection type: Managed cluster.
      • Managed cluster: <ClickHouse®_target_cluster_name> from the drop-down list.
      • Database: db1.
      • User: user1.
      • Password: <user_password>.

   2. Create a Snapshot and replication-type transfer configured to use the new endpoints.

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

   1. In the object-storage-to-clickhouse.tf file, specify the following settings:

      • source_endpoint_id: Source endpoint ID.
      • 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.

   4. The transfer will activate automatically upon creation. Wait for its status to change to Replicating.

Test your transferTest your transfer

Make sure the transfer works correctly by testing copying and replication.

Test copyingTest copying

1. Connect to the db1 database in the Managed Service for ClickHouse® target cluster.

2. Run this query:

   SELECT * FROM db1.table1;
   

   Response example

     __file_name  | __row_index | Id |  Name
   --------------+-------------+----+--------
   demo_data1.csv |           1 |  1 | Anna
   demo_data1.csv |           2 |  2 | Robert
   demo_data1.csv |           3 |  3 | Umar
   demo_data1.csv |           4 |  4 | Algul
   demo_data1.csv |           5 |  5 | Viktor
   

Test replicationTest replication

1. Upload the demo_data2.csv file to the Object Storage bucket.

2. Verify that the data from demo_data2.csv has been loaded into the target database:

   1. Connect to the db1 database in the Managed Service for ClickHouse® target cluster.

   2. Run this query:

      SELECT * FROM db1.table1;
      

      Response example

        __file_name  | __row_index | Id |  Name
      --------------+-------------+----+--------
      demo_data1.csv |           1 |  1 | Anna
      demo_data1.csv |           2 |  2 | Robert
      demo_data1.csv |           3 |  3 | Umar
      demo_data1.csv |           4 |  4 | Algul
      demo_data1.csv |           5 |  5 | Viktor
      demo_data2.csv |           1 |  6 | Maria
      demo_data2.csv |           2 |  7 | Alex
      

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 endpoint.

3. Delete the objects from the bucket.

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

   Manually

   Using Terraform

   1. Delete the target endpoint.
   2. Delete the Managed Service for ClickHouse® cluster.
   3. Delete the Object Storage bucket.

   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.