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

# force_* session settings

> ClickHouse session settings in the force_* generated group.

export const SettingsInfoBlock = ({type, default_value, changeable_without_restart}) => {
  return <div className="not-prose" style={{
    display: "flex",
    flexWrap: "wrap",
    alignItems: "baseline",
    columnGap: "0.5rem",
    rowGap: "0.125rem",
    margin: "0.375rem 0",
    fontSize: "0.8125rem",
    lineHeight: "1.125rem"
  }}>
      <div style={{
    fontWeight: 600,
    opacity: 0.72
  }}>Type</div>
      <div style={{
    overflowWrap: "anywhere"
  }}>{type}</div>
      <div style={{
    fontWeight: 600,
    opacity: 0.72,
    marginInlineStart: "0.5rem"
  }}>Default</div>
      <div style={{
    overflowWrap: "anywhere"
  }}>{default_value}</div>
      {changeable_without_restart && <div style={{
    fontWeight: 600,
    opacity: 0.72,
    marginInlineStart: "0.5rem"
  }}>
          Changeable without restart
        </div>}
      {changeable_without_restart && <div style={{
    overflowWrap: "anywhere"
  }}>
          {changeable_without_restart}
        </div>}
    </div>;
};

These settings are available in [system.settings](/docs/reference/system-tables/settings) and are autogenerated from [source](https://github.com/ClickHouse/ClickHouse/blob/master/src/Core/Settings.cpp).

<h2 id="force_aggregate_partitions_independently">
  force\_aggregate\_partitions\_independently
</h2>

<SettingsInfoBlock type="Bool" default_value="0" />

Force the use of optimization when it is applicable, but heuristics decided not to use it

<h2 id="force_aggregation_in_order">
  force\_aggregation\_in\_order
</h2>

<SettingsInfoBlock type="Bool" default_value="0" />

The setting is used by the server itself to support distributed queries. Do not change it manually, because it will break normal operations. (Forces use of aggregation in order on remote nodes during distributed aggregation).

<h2 id="force_data_skipping_indices">
  force\_data\_skipping\_indices
</h2>

Disables query execution if passed data skipping indices wasn't used.

Consider the following example:

```sql theme={null}
CREATE TABLE data
(
    key Int,
    d1 Int,
    d1_null Nullable(Int),
    INDEX d1_idx d1 TYPE minmax GRANULARITY 1,
    INDEX d1_null_idx assumeNotNull(d1_null) TYPE minmax GRANULARITY 1
)
Engine=MergeTree()
ORDER BY key;

SELECT * FROM data_01515;
SELECT * FROM data_01515 SETTINGS force_data_skipping_indices=''; -- query will produce CANNOT_PARSE_TEXT error.
SELECT * FROM data_01515 SETTINGS force_data_skipping_indices='d1_idx'; -- query will produce INDEX_NOT_USED error.
SELECT * FROM data_01515 WHERE d1 = 0 SETTINGS force_data_skipping_indices='d1_idx'; -- Ok.
SELECT * FROM data_01515 WHERE d1 = 0 SETTINGS force_data_skipping_indices='`d1_idx`'; -- Ok (example of full featured parser).
SELECT * FROM data_01515 WHERE d1 = 0 SETTINGS force_data_skipping_indices='`d1_idx`, d1_null_idx'; -- query will produce INDEX_NOT_USED error, since d1_null_idx is not used.
SELECT * FROM data_01515 WHERE d1 = 0 AND assumeNotNull(d1_null) = 0 SETTINGS force_data_skipping_indices='`d1_idx`, d1_null_idx'; -- Ok.
```

<h2 id="force_grouping_standard_compatibility">
  force\_grouping\_standard\_compatibility
</h2>

<SettingsInfoBlock type="Bool" default_value="1" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "22.9"},{"label": "1"},{"label": "Make GROUPING function output the same as in SQL standard and other DBMS"}]}]} />

Make GROUPING function to return 1 when argument is not used as an aggregation key

<h2 id="force_index_by_date">
  force\_index\_by\_date
</h2>

<SettingsInfoBlock type="Bool" default_value="0" />

Disables query execution if the index can't be used by date.

Works with tables in the MergeTree family.

If `force_index_by_date=1`, ClickHouse checks whether the query has a date key condition that can be used for restricting data ranges. If there is no suitable condition, it throws an exception. However, it does not check whether the condition reduces the amount of data to read. For example, the condition `Date != ' 2000-01-01 '` is acceptable even when it matches all the data in the table (i.e., running the query requires a full scan). For more information about ranges of data in MergeTree tables, see [MergeTree](/docs/reference/engines/table-engines/mergetree-family/mergetree).

<h2 id="force_primary_key">
  force\_primary\_key
</h2>

<SettingsInfoBlock type="Bool" default_value="0" />

Disables query execution if indexing by the primary key is not possible.

Works with tables in the MergeTree family.

If `force_primary_key=1`, ClickHouse checks to see if the query has a primary key condition that can be used for restricting data ranges. If there is no suitable condition, it throws an exception. However, it does not check whether the condition reduces the amount of data to read. For more information about data ranges in MergeTree tables, see [MergeTree](/docs/reference/engines/table-engines/mergetree-family/mergetree).

<h2 id="force_remove_data_recursively_on_drop">
  force\_remove\_data\_recursively\_on\_drop
</h2>

<SettingsInfoBlock type="Bool" default_value="0" />

Recursively remove data on DROP query. Avoids 'Directory not empty' error, but may silently remove detached data