Sync data from RudderStack to ClickHouse.
ClickHouse is an open-source, column-oriented database management system mainly used for online analytical processing (OLAP). It is fast, and allows for real-time analysis of your data.
Refer to the Warehouse Schema
guide for more information on how the events are mapped to the tables in ClickHouse.
Setting user permissions in ClickHouse
Make sure your ClickHouse user has read access to
system.columns table for fetching the table schemas.
You also to need to set
best_effort for ClickHouse to parse all ISO 8601 date and time formats:
set date_time_input_format = 'best_effort';
RudderStack uses the
UInt8 datatype to set Boolean values and map
UInt8to Boolean internally. So when a schema is fetched from ClickHouse, RudderStack treats
UInt8 as Boolean.
If you are creating tables in the same database where RudderStack loads, it is highly recommend to not use
UInt8as a datatype except for Boolean values (0,1).
Configuring ClickHouse in RudderStack
To send event data to ClickHouse, you first need to add it as a destination in RudderStack and connect it to your data source. Once the destination is enabled, events will automatically start flowing to ClickHouse via RudderStack.
To configure ClickHouse as a destination in RudderStack, follow these steps:
- In your RudderStack dashboard, set up the data source. Then, select ClickHouse from the list of destinations.
- Assign a name to your destination and then click Next.
- Host: The host name of your ClickHouse database.
- Port: The TCP port of your ClickHouse host. If you want the connection to be secure, use the secure TCP port
9440. Refer to the ClickHouse guide for more information.
- Database: The database name in your ClickHouse instance where the data gets loaded.
- Cluster: The name of your ClickHouse cluster. If you are running a single host ClickHouse cluster, leave this field blank.
- User: The name of the user with the required read/write access to the above database.
- Password: The password for the above user.
- Secure: Enable this setting to establish a secure connection.
- Sync Frequency: Specify how often RudderStack should sync the data to your ClickHouse database.
- Sync Starting At: This optional setting lets you specify the particular time of the day (in UTC) when you want RudderStack to sync the data to the warehouse.
- Exclude Window: This optional setting lets you set a time window when RudderStack will not sync the data to your database.
Configuring the object storage
RudderStack lets you configure the following object storage configuration settings while setting up your ClickHouse destination:
- Use RudderStack-managed object storage: Enable this setting to use RudderStack-managed buckets for object storage.
This option is applicable only for RudderStack-hosted data planes. For self-hosted data planes
, you will have to specify your own object storage configuration settings.
See How RudderStack stores data in an object storage platform for more information.
IPs to be allowlisted
To enable network access to RudderStack, allowlist the following RudderStack IPs depending on your region and RudderStack Cloud plan:
|Free, Starter, and Growth
All the outbound traffic is routed through these RudderStack IPs.
How does RudderStack de-duplicate the events that are loaded into the warehouse?
RudderStack creates tables with the engine
ReplacingMergeTree order by (received_at, id) and column
ReplacingMergeTree replaces the latest event which has the same
received_at, id while merging. Note that
Nullable is not applicable for
How does RudderStack merge the user properties in the user’s table?
For the user’s table, RudderStack creates a table with an engine
AggregatingMergeTree ordered by
id and a column
SimpleAggregateFunction(anyLast, Nullable(dataType)). Merging the columns with the same
idpicks the last value which is not null. Note that
Nullable is not applicable for
How does RudderStack handle cases when loading data into ClickHouse?
RudderStack converts the event keys into the lower case before exporting the data into ClickHouse. This is so that it does not create two tables in case the event name has two different cases.
For a more comprehensive FAQ list, refer to the Warehouse FAQ
Questions? Contact us by email or on