> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-postgresql-tls-support.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# http_max_* 会话设置

> 属于 http_max_* 自动生成分组的 ClickHouse 会话设置。

export const VersionHistory = ({rows = []}) => {
  if (rows.length === 0) {
    return null;
  }
  const headers = ["版本", "默认值", "注释"];
  const border = "1px solid rgba(128, 128, 128, 0.3)";
  const cell = {
    border,
    padding: "0.25rem 0.5rem",
    textAlign: "start",
    verticalAlign: "top"
  };
  return <details className="not-prose" style={{
    border,
    borderRadius: "0.5rem",
    margin: "0.5rem 0",
    padding: "0.5rem 0.75rem",
    fontSize: "0.8125rem",
    lineHeight: "1.125rem"
  }}>
      <summary style={{
    cursor: "pointer",
    fontWeight: 600,
    opacity: 0.72
  }}>
        版本历史
      </summary>
      <table style={{
    borderCollapse: "collapse",
    width: "100%",
    margin: "0.5rem 0 0"
  }}>
        <thead>
          <tr>
            {headers.map(header => <th key={header} style={{
    ...cell,
    fontWeight: 600,
    opacity: 0.72
  }}>
                {header}
              </th>)}
          </tr>
        </thead>
        <tbody>
          {rows.map((row, row_index) => <tr key={row.id ?? row_index}>
              {(row.items ?? []).map((item, item_index) => <td key={item_index} style={{
    ...cell,
    overflowWrap: "anywhere"
  }}>
                  {item?.label}
                </td>)}
            </tr>)}
        </tbody>
      </table>
    </details>;
};

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
  }}>类型</div>
      <div style={{
    overflowWrap: "anywhere"
  }}>{type}</div>
      <div style={{
    fontWeight: 600,
    opacity: 0.72,
    marginInlineStart: "0.5rem"
  }}>默认值</div>
      <div style={{
    overflowWrap: "anywhere"
  }}>{default_value}</div>
      {changeable_without_restart && <div style={{
    fontWeight: 600,
    opacity: 0.72,
    marginInlineStart: "0.5rem"
  }}>
          无需重启即可更改
        </div>}
      {changeable_without_restart && <div style={{
    overflowWrap: "anywhere"
  }}>
          {changeable_without_restart}
        </div>}
    </div>;
};

这些设置可在 [system.settings](/zh/reference/system-tables/settings) 中查看，并由 [源代码](https://github.com/ClickHouse/ClickHouse/blob/master/src/Core/Settings.cpp) 自动生成。

<div id="http_max_field_name_size">
  ## http\_max\_field\_name\_size
</div>

<SettingsInfoBlock type="UInt64" default_value="4096" />

HTTP 请求头、查询参数和表单数据中的字段名称最大长度。

<div id="http_max_field_value_size">
  ## http\_max\_field\_value\_size
</div>

<SettingsInfoBlock type="UInt64" default_value="131072" />

HTTP 请求头、查询参数和表单数据中字段值的最大长度。

<div id="http_max_fields">
  ## http\_max\_fields
</div>

<SettingsInfoBlock type="UInt64" default_value="1000" />

HTTP 请求头、查询参数和表单数据中的最大字段数。

<div id="http_max_multipart_form_data_size">
  ## http\_max\_multipart\_form\_data\_size
</div>

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

multipart/form-data 内容大小上限。此设置无法通过 URL 参数解析，应在用户 profile 中设置。请注意，在查询执行开始之前，内容会先在内存中解析并创建外部表。此外，这是在该阶段唯一会生效的限制 (内存使用量上限和最大执行时间限制在读取 HTTP form data 时不起作用) 。

<div id="http_max_request_header_size">
  ## http\_max\_request\_header\_size
</div>

<SettingsInfoBlock type="UInt64" default_value="10485760" />

所有 HTTP 请求头 (名称和值合计) 的最大总大小，以字节为单位。

<div id="http_max_request_param_data_size">
  ## http\_max\_request\_param\_data\_size
</div>

<SettingsInfoBlock type="UInt64" default_value="10485760" />

预定义 HTTP 请求中用作查询参数的请求数据大小上限。

<div id="http_max_tries">
  ## http\_max\_tries
</div>

<SettingsInfoBlock type="UInt64" default_value="10" />

通过 HTTP 读取时的最大重试次数。

<div id="http_max_uri_size">
  ## http\_max\_uri\_size
</div>

<SettingsInfoBlock type="UInt64" default_value="1048576" />

设置 HTTP 请求 URI 的最大长度。

可能的值：

* 正整数。