> ## Documentation Index
> Fetch the complete documentation index at: https://docs.activeviam.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ConnectionConfig

<span id="atoti_directquery_clickhouse.ConnectionConfig" />

> atoti\_directquery\_clickhouse.ConnectionConfig(<br />
>     \*,<br />
>     *password*: [str](https://docs.python.org/3/library/stdtypes.html#str) | [None](https://docs.python.org/3/library/constants.html#None) = `None`,<br />
>     *column\_clustered\_queries*: 'all' | 'feeding' = `'feeding'`,<br />
>     *feeding\_query\_timeout*: Duration = `datetime.timedelta(seconds=3600)`,<br />
>     *lookup\_mode*: 'allow' | 'warn' | 'deny' = `'warn'`,<br />
>     *max\_sub\_queries*: Annotated\[[int](https://docs.python.org/3/library/functions.html#int), Field(gt=0)] = `500`,<br />
>     *query\_timeout*: Duration = `datetime.timedelta(seconds=300)`,<br />
>     *url*: [str](https://docs.python.org/3/library/stdtypes.html#str),<br />
> )

Config to connect to a ClickHouse database.

<Callout icon="link">
  **See also**:
  [`atoti_directquery_snowflake.ConnectionConfig`](./atoti_directquery_snowflake.ConnectionConfig#atoti_directquery_snowflake.ConnectionConfig) for an example.
</Callout>

### Attributes

<h4 id="atoti_directquery_clickhouse.ConnectionConfig.url">
  *url*
</h4>

The connection string.

The pattern is: `(clickhouse|ch):(https|http|...)://login:password@host:port/database?prop=value`.
For example: `"clickhouse:https://user:password@localhost:8123/mydb"`.
When a part is missing, its default value will be used.

<h4 id="atoti_directquery_clickhouse.ConnectionConfig.column_clustered_queries">
  *column\_clustered\_queries*
</h4>

Control which queries will use clustering columns.

<h4 id="atoti_directquery_clickhouse.ConnectionConfig.feeding_query_timeout">
  *feeding\_query\_timeout*
</h4>

Timeout for queries performed on the external database during feeding phases.

The feeding phases are:

* the initial load to feed [`aggregate_providers`](./atoti.Cube.aggregate_providers#atoti.Cube.aggregate_providers) and [`hierarchies`](./atoti.Cube.hierarchies#atoti.Cube.hierarchies);
* the refresh operations.

<h4 id="atoti_directquery_clickhouse.ConnectionConfig.lookup_mode">
  *lookup\_mode*
</h4>

Whether lookup queries on the external database are allowed.

Lookup can be very slow and expensive as the database may not enforce primary keys.

<h4 id="atoti_directquery_clickhouse.ConnectionConfig.max_sub_queries">
  *max\_sub\_queries*
</h4>

Maximum number of sub queries performed when splitting a query into multi-step queries.

<h4 id="atoti_directquery_clickhouse.ConnectionConfig.password">
  *password*
</h4>

The password to connect to the database.

Passing it in this separate attribute prevents it from being logged alongside the connection string.

If `None`, a password is expected to be present in [`url`](#atoti_directquery_clickhouse.ConnectionConfig.url).

<h4 id="atoti_directquery_clickhouse.ConnectionConfig.query_timeout">
  *query\_timeout*
</h4>

Timeout for queries performed on the external database outside feeding phases.