> ## 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.

# format_capn_* format settings

> ClickHouse format settings in the format_capn_* 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 autogenerated from [source](https://github.com/ClickHouse/ClickHouse/blob/master/src/Core/FormatFactorySettings.h).

<h2 id="format_capn_proto_enum_comparising_mode">
  format\_capn\_proto\_enum\_comparising\_mode
</h2>

<SettingsInfoBlock type="CapnProtoEnumComparingMode" default_value="by_values" />

How to map ClickHouse Enum and CapnProto Enum

<h2 id="format_capn_proto_max_message_size">
  format\_capn\_proto\_max\_message\_size
</h2>

<SettingsInfoBlock type="UInt64" default_value="1073741824" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "25.12"},{"label": "1073741824"},{"label": "Prevent allocating large amount of memory"}]}]} />

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

<h2 id="format_capn_proto_use_autogenerated_schema">
  format\_capn\_proto\_use\_autogenerated\_schema
</h2>

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

Use autogenerated CapnProto schema when format\_schema is not set