General questions about Managed Service for ClickHouse®

• What is Managed Service for ClickHouse®?

• What is ClickHouse® used for? Which DBMS should I select?

• What part of database management and maintenance is Managed Service for ClickHouse® responsible for?

• Which tasks are best addressed using Managed Service for ClickHouse®, and which using VMs with databases?

• What is a database host and database cluster?

• How do I get started with Managed Service for ClickHouse®?

• How many database hosts can there be in one cluster?

• How can I access a running DB host?

• How many clusters can I create within a single cloud?

• How are DB clusters maintained?

• How do I edit external dictionaries?

• Which ClickHouse® version does Managed Service for ClickHouse® use?

• Which ClickHouse® version should I choose?

• What happens when a new DBMS version is released?

• What happens when a DBMS version becomes deprecated?

• How do you calculate usage cost for a database host?

• How much does it cost to use my cluster?

• How can I change the computing resources and storage size for a database cluster?

• How can I fix the no permission error when connecting a service account to the cluster?

• How do I get the logs of my actions in the services?

What is Managed Service for ClickHouse®?What is Managed Service for ClickHouse®?

Managed Service for ClickHouse® is a solution that helps you create, operate, and scale ClickHouse® databases in the cloud.

With Managed Service for ClickHouse®, you can:

• Create a database with the performance parameters tailored to your needs.
• Scale computing power and dedicated storage capacity for your databases as needed.
• Get database logs.

Managed Service for ClickHouse® takes over time-consuming ClickHouse® infrastructure administration tasks:

• Monitors resource usage.
• Automatically creates DB backups.
• Provides fault tolerance through automatic failover to backup replicas.
• Keeps database software updated.

You work with a Managed Service for ClickHouse® database cluster as if it were a regular database in your local infrastructure This allows you to manage internal database settings to meet your app requirements.

What is ClickHouse® used for? Which DBMS should I select?What is ClickHouse® used for? Which DBMS should I select?

ClickHouse® is designed primarily for analytics (OLAP) and only supports adding and reading data. You can update data but with certain limitations. For other purposes, you might want to use another DBMS.

What is Managed Service for ClickHouse®'s share of database management and maintenance work?What is Managed Service for ClickHouse®'s share of database management and maintenance work?

When you create clusters, Managed Service for ClickHouse® allocates resources, installs the DBMS, and creates databases.

For all created and running databases, Managed Service for ClickHouse® automatically creates backups and applies fixes and updates.

Managed Service for ClickHouse® also enables data replication between database hosts (both within and across availability zones) and automatically fails over to a backup replica if a failure occurs.

Be mindful of what is what is controlled by the service, and what by the Yandex Cloud customer. Understanding these control zones will help you use your cloud resources effectively and avoid potential database-related problems. For more information, see Zones of control between managed database (MDB) service users and Yandex Cloud.

Not sure whether to use Managed Service for ClickHouse® or VMs running databases?Not sure whether to use Managed Service for ClickHouse® or VMs running databases?

Yandex Cloud offers two ways to work with databases:

• Managed Service for ClickHouse®: Enables you to operate template databases without needing to manage their administration.
• Yandex Compute Cloud VM: Enables you to create and configure your own databases. With this approach, you can use any database management systems, access databases via SSH, and more.

What is a database host and database cluster?What is a database host and database cluster?

A database host is an isolated database environment in the cloud with dedicated computing resources and reserved storage capacity.

A database cluster is one or more database hosts with the option to configure replication.

How do I get started with Managed Service for ClickHouse®?How do I get started with Managed Service for ClickHouse®?

Managed Service for ClickHouse® is available to all registered Yandex Cloud users.

To create a database cluster in Managed Service for ClickHouse®, you need to define its settings:

• Host class (performance parameters, such as CPUs, RAM, etc.).
• Storage size (fully reserved when creating the cluster).
• Network your cluster will be connected to.
• Number of hosts for your cluster and availability zone for each host.

For more information, see Getting started.

How many database hosts does a cluster support?How many database hosts does a cluster support?

The minimum number of hosts in a cluster depends on the following:

• Storage type:

  • At least three hosts for non-replicated SSDs (network-ssd-nonreplicated).

  • At least two hosts for local SSDs (local-ssd).

  • At least one host for the following:

    • Network HDDs (network-hdd).
    • Network SSDs (network-ssd).
    • Ultra high-speed network SSDs with three replicas (network-ssd-io-m3).

• Cluster sharding. When sharding is enabled, you need to multiply the minimum number of hosts for the selected disk type by the number of shards.

  For more information on the features and limitations of sharding in ClickHouse®, see this article.

The maximum number of hosts per cluster cannot exceed the set limits.

For more information, see Quotas and limits.

How can I access a running DB host?How can I access a running DB host?

You can connect to Managed Service for ClickHouse® databases using standard DBMS methods.

Learn more about connecting to clusters here.

How many clusters can I create within a single cloud?How many clusters can I create within a single cloud?

For more information on MDB technical and organizational limitations, see Quotas and limits.

How are DB clusters maintained?How are DB clusters maintained?

In Managed Service for ClickHouse®, maintenance implies:

• Automatic installation of DBMS updates and fixes for DB hosts (including disabled clusters).
• Changes to the host class and storage size.
• Other Managed Service for ClickHouse® maintenance activities.

For more information, see Maintenance.

How do I edit external dictionaries?How do I edit external dictionaries?

To rename a dictionary, run this query:

RENAME DICTIONARY <dictionary_name> TO <new_name>

For other changes, use the update API method.

Which ClickHouse® version does Managed Service for ClickHouse® use?Which ClickHouse® version does Managed Service for ClickHouse® use?

Managed Service for ClickHouse® uses multiple latest stable versions of ClickHouse®. For more information, see ClickHouse® versioning policy.

Which ClickHouse® version should I choose?Which ClickHouse® version should I choose?

We recommend the latest available LTS version of ClickHouse®. For more information, see ClickHouse® versioning policy.

What happens when a new DBMS version is released?What happens when a new DBMS version is released?

When new minor versions are released, the cluster software is automatically updated after a short testing period.

Owners of the affected DB clusters are notified of an expected maintenance period and DB availability in advance.

What happens when a DBMS version becomes deprecated?What happens when a DBMS version becomes deprecated?

When a DBMS version becomes deprecated, Managed Service for ClickHouse® automatically sends email notifications to the owners of database clusters created with this version.

New hosts can no longer be created using deprecated DBMS versions. Clusters running a deprecated ClickHouse® version are updated according to the versioning policy.

Owners of the affected DB clusters are notified of an expected maintenance period and DB availability in advance.

How do you calculate usage cost for a database host?How do you calculate usage cost for a database host?

In Managed Service for ClickHouse®, the usage cost is calculated based on the following:

• Selected host class.
• Size of the storage reserved for the database host.
• Size of the database cluster backups. Backup size equal to the storage size is free of charge. Backup storage that exceeds this size is charged based on the pricing policy.
• Database host uptime in hours. Partial hours are rounded up to the nearest whole hour. For the cost per hour of operation for each host class, see Pricing policy.

How much does it cost to use my cluster?How much does it cost to use my cluster?

In the management console, navigate to the folder dashboard, select Managed Service for ClickHouse, and click the cluster you need. On the right side of the screen, you will see the cluster usage cost per month. For more information, see Pricing policy.

How can I change the computing resources and storage size for a database cluster?How can I change the computing resources and storage size for a database cluster?

You can change computing resources and storage size in the management console. All you need to do is choose a different host class for the relevant cluster.

The cluster settings update within 30 minutes. This period may also include other cluster maintenance activities, such as installing updates.

How can I fix the no permission error when assigning a service account to a cluster?How can I fix the no permission error when assigning a service account to a cluster?

Error message:

ERROR: rpc error: code = PermissionDenied desc = you do not have permission to access the requested service account or service account does not exist

The error occurs in the following cases:

• You are creating or modifying a cluster and linking it to a service account.
• You are restoring a cluster linked to a service account from its backup.

To fix this error, assign your Yandex Cloud account the iam.serviceAccounts.user role or higher.

Does the service meet the requirements of the Russian Federation Federal Law 152-FZ on personal data?Does the service meet the requirements of the Russian Federation Federal Law 152-FZ on personal data?

Yes, it does. You can read the full security audit conclusion here.

Can I get logs of my operations in Yandex Cloud?Can I get logs of my operations in Yandex Cloud?

Yes, you can request information about operations with your resources from Yandex Cloud logs. Do it by contacting support.

ClickHouse® is a registered trademark of ClickHouse, Inc.