Scaling MySQL ClickPipes via OpenAPI

Scaling API may be useful for:

Large initial loads (over 4 TB)
Migrating a moderate amount of data as quickly as possible
Supporting over 8 CDC ClickPipes under the same service

Before attempting to scale up, consider:

Ensuring the source DB has sufficient available capacity
First adjusting initial load parallelism and partitioning when creating a ClickPipe
Checking for long-running transactions on the source that could be causing CDC delays

Increasing the scale will proportionally increase your ClickPipes compute costs. If you’re scaling up just for the initial loads, it’s important to scale down after the snapshot is finished to avoid unexpected charges. For more details on pricing, see ClickPipes pricing.

Prerequisites for this process

Before you get started you will need:

ClickHouse API key with Admin permissions on the target ClickHouse Cloud service.
A DB ClickPipe (Postgres, MySQL or MongoDB) provisioned in the service at some point in time. CDC infrastructure gets created along with the first ClickPipe, and the scaling endpoints become available from that point onwards.

Steps to scale DB ClickPipes

Set the following environment variables before running any commands:

ORG_ID=<Your ClickHouse organization ID>
SERVICE_ID=<Your ClickHouse service ID>
KEY_ID=<Your ClickHouse key ID>
KEY_SECRET=<Your ClickHouse key secret>

Fetch the current scaling configuration (optional):

curl --silent --user $KEY_ID:$KEY_SECRET \
https://api.clickhouse.cloud/v1/organizations/$ORG_ID/services/$SERVICE_ID/clickpipesCdcScaling \
| jq

# example result:
{
  "result": {
    "replicaCpuMillicores": 2000,
    "replicaMemoryGb": 8
  },
  "requestId": "04310d9e-1126-4c03-9b05-2aa884dbecb7",
  "status": 200
}

Set the desired scaling. Supported configurations include 1-24 CPU cores with memory (GB) set to 4× the core count:

cat <<EOF | tee cdc_scaling.json
{
  "replicaCpuMillicores": 24000,
  "replicaMemoryGb": 96
}
EOF

curl --silent --user $KEY_ID:$KEY_SECRET \
-X PATCH -H "Content-Type: application/json" \
https://api.clickhouse.cloud/v1/organizations/$ORG_ID/services/$SERVICE_ID/clickpipesCdcScaling \
-d @cdc_scaling.json | jq

Wait for the configuration to propagate (typically 3-5 minutes). After the scaling is finished, the GET endpoint will reflect the new values:

curl --silent --user $KEY_ID:$KEY_SECRET \
https://api.clickhouse.cloud/v1/organizations/$ORG_ID/services/$SERVICE_ID/clickpipesCdcScaling \
| jq

# example result:
{
  "result": {
    "replicaCpuMillicores": 24000,
    "replicaMemoryGb": 96
  },
  "requestId": "5a76d642-d29f-45af-a857-8c4d4b947bf0",
  "status": 200
}