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. 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 startedGetting started

Prepare the infrastructure:

Prepare the test dataPrepare the 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.

Prepare and activate the transferPrepare and activate the transfer

1. Create a source endpoint of the Object Storage type with the following settings:

   • Database type: Object Storage.

   • Bucket: Bucket name in Object Storage.

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

   • Secret Access Key: Private part of the service account static key. If you created your infrastructure with 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 field names and data types:

     • Id: Int64
     • Name: UTF8

   Leave the default values for other properties.

2. Create a target endpoint and a transfer:

   Manually

   Using Terraform

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

      • 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 transfer of the Snapshot and replication type that will use the created 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 parameters:

      • source_endpoint_id: Source endpoint ID.
      • transfer_enabled: 1 to create a transfer.

   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.

Test the transferTest the transfer

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

Test the copy processTest the copy process

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

2. Run the following 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 the replication processTest the replication process

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

2. Make sure the data from demo_data2.csv has been added to the target database:

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

   2. Run the following 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

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

• Transfer.

• Source endpoint.

• Objects from the bucket.

• Delete the other resources depending on how they were created:

  Manually

  Using Terraform

  • Target endpoint.
  • Managed Service for ClickHouse® cluster.
  • 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.