Aiven for ClickHouse® limits and limitations
By respecting the Aiven for ClickHouse® restrictions and quotas, you can improve the security and productivity of your service workloads.
Limitations
From the information about restrictions on using Aiven for ClickHouse, you can draw conclusions on how to get your service to operate closer to its full potential. Use Recommended approach as guidelines on how to work around specific restrictions.
| Name | Description | Recommended approach |
|---|---|---|
| Backups - one snapshot a day | Since Aiven for ClickHouse service takes a single snapshot a day only:
| |
| Service integrations | You can integrate your Aiven for ClickHouse service with PostgreSQL® and Kafka® only. | - |
Table engines support |
| Use the available table engines listed in Supported table engines in Aiven for ClickHouse. |
Log table engine support | Log engine is not supported in Aiven for ClickHouse. | For storing data, use the Buffer engine instead of the Log engine. |
Kafka table engine support | The Kafka table engine is supported via integration only, not by creating a table in SQL. | - |
Kafka Schema Registry | Kafka Schema Registry is supported with Aiven for Apache Kafka® and not with an external Kafka endpoint. | - |
Cloud availability | Available on AWS, GCP, and Azure only | Use the available cloud providers. |
Querying all shards at once | If you have a sharded plan, you must use a distributed table on top of your MergeTree table to query all the shards at the same time, and you should use it for inserts too. | Use a distributed table with sharded plans. See Query data across shards. |
ON CLUSTER queries | Aiven for ClickHouse doesn't support ON CLUSTER queries because it actually runs each data definition query on all the servers of the cluster without using ON CLUSTER. | Run queries without |
Creating a database using SQL | You cannot create a database directly using SQL, for example, if you'd like to add a non-default database. | Use the Aiven's public API. |
Scaling down the number of nodes | You only can scale up the number of nodes in a cluster. | - |
Limits
Service limits are determined by a plan that this service uses.
| Aiven for ClickHouse | Hobbyist | Startup | Business | Premium |
|---|---|---|---|---|
| VMs | 1 | 1 | 3 | 6 - 30 |
| CPU per VM | 1 (2 for AWS only) | 2 | 2 - 8 | 2 - 8 |
| RAM per VM | 4 GB | 16 GB | 16 - 64 GB | 16 - 64 GB |
| Total storage | 180 GB | 1150 GB | 1150 - 4600 GB | 2300 - 46000 GB |
| Maximum concurrent queries | 25 queries per 4 GB of RAM | 100 queries per 16 GB of RAM | 100 queries per 16 GB of RAM | 100 queries per 16 GB of RAM |
| Maximum concurrent connections | 1000 connections per node | 4000 connections per node | 4000 connections per node | 4000 connections per node |
Total storage represents the maximum amount of data you can insert into a service, which doesn't depend on the number of nodes.
The inserted data is replicated on all available nodes. How many times it's replicated depends on the number of nodes and the number of shards:
number_of_data_replication_times = number_of_nodes / number_of_shards
Examples
-
Service plan with one shard
The Startup-16 plan has 1150 GB of total storage per VM, same as with the Business-16 plan. Since the Business-16 plan offers three VMs, your total storage is 3450 GB, but effectively it's still 1150 GB because that’s the maximum a single node can hold.
-
Service plan with two shards
The Premium-6x-16 plan has two shards and six servers, each server with 1150 GB of storage. The data you insert is replicated three times.
If you need a custom plan with capacity beyond the listed limits, contact us.