Format Settings

[Edit this page](https://github.com/ClickHouse/ClickHouse/tree/master/docs/en/operations/settings/settings-formats.md)

These settings are autogenerated from [source](https://github.com/ClickHouse/ClickHouse/blob/master/src/Core/FormatFactorySettings.h).

## allow\_special\_bool\_values\_inside\_variant[​](#allow_special_bool_values_inside_variant "Direct link to allow_special_bool_values_inside_variant")

Allows to parse Bool values inside Variant type from special text bool values like "on", "off", "enable", "disable", etc.

## bool\_false\_representation[​](#bool_false_representation "Direct link to bool_false_representation")

Text to represent false bool value in TSV/CSV/Vertical/Pretty formats.

## bool\_true\_representation[​](#bool_true_representation "Direct link to bool_true_representation")

Text to represent true bool value in TSV/CSV/Vertical/Pretty formats.

## check\_conversion\_from\_numbers\_to\_enum[​](#check_conversion_from_numbers_to_enum "Direct link to check_conversion_from_numbers_to_enum")

Throw an exception during Numbers to Enum conversion if the value does not exist in Enum.

Possible values:

- 0 — Disabled.
- 1 — Enabled.

**Example**

```
CREATE TABLE tab (
  val Enum('first' = 1, 'second' = 2, 'third' = 3)
) ENGINE = Memory;

INSERT INTO tab SETTINGS check_conversion_from_numbers_to_enum = 1 VALUES (4); -- returns an error
```

## column\_names\_for\_schema\_inference[​](#column_names_for_schema_inference "Direct link to column_names_for_schema_inference")

The list of column names to use in schema inference for formats without column names. The format: 'column1,column2,column3,...'

## date\_time\_64\_output\_format\_cut\_trailing\_zeros\_align\_to\_groups\_of\_thousands[​](#date_time_64_output_format_cut_trailing_zeros_align_to_groups_of_thousands "Direct link to date_time_64_output_format_cut_trailing_zeros_align_to_groups_of_thousands")

Dynamically trim the trailing zeros of datetime64 values to adjust the output scale to [0, 3, 6],
corresponding to 'seconds', 'milliseconds', and 'microseconds'

## date\_time\_input\_format[​](#date_time_input_format "Direct link to date_time_input_format")

Allows choosing a parser of the text representation of date and time.

The setting does not apply to [date and time functions](/docs/sql-reference/functions/date-time-functions).

Possible values:

- `'best_effort'` — Enables extended parsing.

  ClickHouse can parse the basic `YYYY-MM-DD HH:MM:SS` format and all [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) date and time formats. For example, `'2018-06-08T01:02:03.000Z'`.
- `'best_effort_us'` — Similar to `best_effort` (see the difference in [parseDateTimeBestEffortUS](/docs/sql-reference/functions/type-conversion-functions#parseDateTimeBestEffortUS)
- `'basic'` — Use basic parser.

  ClickHouse can parse only the basic `YYYY-MM-DD HH:MM:SS` or `YYYY-MM-DD` format. For example, `2019-08-20 10:18:56` or `2019-08-20`.

Cloud default value: `'best_effort'`.

See also:

- [DateTime data type.](/docs/sql-reference/data-types/datetime)
- [Functions for working with dates and times.](/docs/sql-reference/functions/date-time-functions)

## date\_time\_output\_format[​](#date_time_output_format "Direct link to date_time_output_format")

Allows choosing different output formats of the text representation of date and time.

Possible values:

- `simple` - Simple output format.

  ClickHouse output date and time `YYYY-MM-DD hh:mm:ss` format. For example, `2019-08-20 10:18:56`. The calculation is performed according to the data type's time zone (if present) or server time zone.
- `iso` - ISO output format.

  ClickHouse output date and time in [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) `YYYY-MM-DDThh:mm:ssZ` format. For example, `2019-08-20T10:18:56Z`. Note that output is in UTC (`Z` means UTC).
- `unix_timestamp` - Unix timestamp output format.

  ClickHouse output date and time in [Unix timestamp](https://en.wikipedia.org/wiki/Unix_time) format. For example `1566285536`.

See also:

- [DateTime data type.](/docs/sql-reference/data-types/datetime)
- [Functions for working with dates and times.](/docs/sql-reference/functions/date-time-functions)

## date\_time\_overflow\_behavior[​](#date_time_overflow_behavior "Direct link to date_time_overflow_behavior")

Defines the behavior when [Date](/docs/sql-reference/data-types/date), [Date32](/docs/sql-reference/data-types/date32), [DateTime](/docs/sql-reference/data-types/datetime), [DateTime64](/docs/sql-reference/data-types/datetime64) or integers are converted into Date, Date32, DateTime or DateTime64 but the value cannot be represented in the result type.

Possible values:

- `ignore` — Silently ignore overflows. Result are undefined.
- `throw` — Throw an exception in case of overflow.
- `saturate` — Saturate the result. If the value is smaller than the smallest value that can be represented by the target type, the result is chosen as the smallest representable value. If the value is bigger than the largest value that can be represented by the target type, the result is chosen as the largest representable value.

Default value: `ignore`.

## errors\_output\_format[​](#errors_output_format "Direct link to errors_output_format")

Method to write Errors to text output.

## format\_avro\_schema\_registry\_url[​](#format_avro_schema_registry_url "Direct link to format_avro_schema_registry_url")

For AvroConfluent format: Confluent Schema Registry URL.

## format\_binary\_max\_array\_size[​](#format_binary_max_array_size "Direct link to format_binary_max_array_size")

The maximum allowed size for Array in RowBinary format. It prevents allocating large amount of memory in case of corrupted data. 0 means there is no limit

## format\_binary\_max\_object\_size[​](#format_binary_max_object_size "Direct link to format_binary_max_object_size")

The maximum allowed number of paths in a single Object for JSON type RowBinary format. It prevents allocating large amount of memory in case of corrupted data. 0 means there is no limit

## format\_binary\_max\_string\_size[​](#format_binary_max_string_size "Direct link to format_binary_max_string_size")

The maximum allowed size for String in RowBinary format. It prevents allocating large amount of memory in case of corrupted data. 0 means there is no limit

## format\_capn\_proto\_enum\_comparising\_mode[​](#format_capn_proto_enum_comparising_mode "Direct link to format_capn_proto_enum_comparising_mode")

How to map ClickHouse Enum and CapnProto Enum

## format\_capn\_proto\_max\_message\_size[​](#format_capn_proto_max_message_size "Direct link to format_capn_proto_max_message_size")

Maximum size of a single CapnProto message in bytes. This protects against malformed or corrupted data causing excessive memory allocation. Default is 1 GiB.

## format\_capn\_proto\_use\_autogenerated\_schema[​](#format_capn_proto_use_autogenerated_schema "Direct link to format_capn_proto_use_autogenerated_schema")

Use autogenerated CapnProto schema when format\_schema is not set

## format\_csv\_allow\_double\_quotes[​](#format_csv_allow_double_quotes "Direct link to format_csv_allow_double_quotes")

If it is set to true, allow strings in double quotes.

## format\_csv\_allow\_single\_quotes[​](#format_csv_allow_single_quotes "Direct link to format_csv_allow_single_quotes")

If it is set to true, allow strings in single quotes.

## format\_csv\_delimiter[​](#format_csv_delimiter "Direct link to format_csv_delimiter")

The character to be considered as a delimiter in CSV data. If setting with a string, a string has to have a length of 1.

## format\_csv\_null\_representation[​](#format_csv_null_representation "Direct link to format_csv_null_representation")

Custom NULL representation in CSV format

## format\_custom\_escaping\_rule[​](#format_custom_escaping_rule "Direct link to format_custom_escaping_rule")

Field escaping rule (for CustomSeparated format)

## format\_custom\_field\_delimiter[​](#format_custom_field_delimiter "Direct link to format_custom_field_delimiter")

Delimiter between fields (for CustomSeparated format)