> ## 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.

# max_rand_* 会话设置

> 属于 max_rand_* 生成组的 ClickHouse 会话设置。

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](/docs/zh/reference/system-tables/settings) 中找到，并由 [源代码](https://github.com/ClickHouse/ClickHouse/blob/master/src/Core/Settings.cpp) 自动生成。

<div id="max_rand_distribution_parameter">
  ## max\_rand\_distribution\_parameter
</div>

<SettingsInfoBlock type="Float" default_value="1000000" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.4"},{"label": "1000000"},{"label": "用于限制随机分布函数中形状参数的新设置，可防止在极端输入下出现长时间卡顿。"}]}]} />

`randChiSquared`、`randStudentT` 和 `randFisherF` 等随机分布函数中分布形状参数的最大值。这样可避免参数值过于极端时计算耗时过长。

<div id="max_rand_distribution_trials">
  ## max\_rand\_distribution\_trials
</div>

<SettingsInfoBlock type="UInt64" default_value="1000000000" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.4"},{"label": "1000000000"},{"label": "用于限制随机分布函数试验次数的新设置，可防止在极端输入下卡住。"}]}]} />

`randBinomial` 和 `randNegativeBinomial` 等随机分布函数允许的最大试验次数。这样可防止在试验次数很大时计算时间过长。