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:

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:

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

    <!-- Настройки для запросов из пользовательского интерфейса -->
    <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.