ClickHouse/docs/en/operations/settings/settings_profiles.md

# Settings profiles

A settings profile is a collection of settings grouped under the same name. Each ClickHouse user has a profile.
To apply all the settings in a profile, set 'profile'. Example:

```sql
SET profile = 'web'
```

- Load the 'web' profile. In other words, set all the options that belong to the 'web' profile.

Settings profiles are declared in the user config file. This is usually `users.xml`.
Example:

```xml
<!-- Settings profiles -->
<profiles>
    <!-- Default settings -->
    <default>
    <!-- The maximum number of threads when running a single query. -->
        <max_threads>8</max_threads>
    </default>

    <!-- Settings for quries from the user interface -->
    <web>
        <max_rows_to_read>1000000000</max_rows_to_read>
        <max_bytes_to_read>100000000000</max_bytes_to_read>

        <max_rows_to_group_by>1000000</max_rows_to_group_by>
        <group_by_overflow_mode>any</group_by_overflow_mode>

        <max_rows_to_sort>1000000</max_rows_to_sort>
        <max_bytes_to_sort>1000000000</max_bytes_to_sort>

        <max_result_rows>100000</max_result_rows>
        <max_result_bytes>100000000</max_result_bytes>
        <result_overflow_mode>break</result_overflow_mode>

        <max_execution_time>600</max_execution_time>
        <min_execution_speed>1000000</min_execution_speed>
        <timeout_before_checking_execution_speed>15</timeout_before_checking_execution_speed>

        <max_columns_to_read>25</max_columns_to_read>
        <max_temporary_columns>100</max_temporary_columns>
        <max_temporary_non_const_columns>50</max_temporary_non_const_columns>

        <max_subquery_depth>2</max_subquery_depth>
        <max_pipeline_depth>25</max_pipeline_depth>
        <max_ast_depth>50</max_ast_depth>
        <max_ast_elements>100</max_ast_elements>

        <readonly>1</readonly>
    </web>
</profiles>
```

The example specifies two profiles: `default`  and `web`. The `default` profile has a special purpose: it must always be present and is applied when starting the server. In other words, the 'default' profile contains default settings. The 'web' profile is a regular profile that can be set using the SET query or using a URL parameter in an HTTP query.

Settings profiles can inherit from each other. To use inheritance, indicate the 'profile' setting before the other settings that are listed in the profile.