> ## 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.

# iceberg_* 会话设置

> 属于 iceberg_* 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>;
};

export const ExperimentalBadge = () => {
  return <div className="experimentalBadge">
            <div className="experimentalIcon">
            <svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
                <path strokeWidth="1.25" d="M5.5 2H10.5" stroke="currentColor" strokeLinecap="round" strokeLinejoin="round" />
                <path strokeWidth="1.25" d="M9.50015 2V6.19625L13.4283 12.7425C13.4738 12.8183 13.4985 12.9049 13.4996 12.9934C13.5008 13.0818 13.4785 13.169 13.435 13.246C13.3914 13.323 13.3283 13.3871 13.2519 13.4317C13.1755 13.4764 13.0886 13.4999 13.0002 13.5H3.00015C2.91164 13.5 2.8247 13.4766 2.74822 13.432C2.67174 13.3874 2.60847 13.3233 2.56487 13.2463C2.52126 13.1693 2.49889 13.082 2.50004 12.9935C2.50119 12.905 2.52582 12.8184 2.5714 12.7425L6.50015 6.19625V2" stroke="currentColor" strokeLinecap="round" strokeLinejoin="round" />
                <path strokeWidth="1.25" d="M4.47656 9.56754C5.30344 9.41254 6.47656 9.47942 7.99969 10.25C10.0153 11.2707 11.4216 11.0569 12.2184 10.7282" stroke="currentColor" strokeLinecap="round" strokeLinejoin="round" />
            </svg>
        </div>
            Experimental 功能。 <u><a href="/docs/docs/beta-and-experimental-features#experimental-features">了解详情。</a></u>
        </div>;
};

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

<div id="iceberg_delete_data_on_drop">
  ## iceberg\_delete\_data\_on\_drop
</div>

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

<VersionHistory rows={[{"id": "row-1","items": [{"label": "25.9"},{"label": "0"},{"label": "新增设置"}]}]} />

执行 drop 时，是否删除所有 Iceberg 文件。

<div id="iceberg_manifest_min_count_to_compact">
  ## iceberg\_manifest\_min\_count\_to\_compact
</div>

<ExperimentalBadge />

<SettingsInfoBlock type="UInt64" default_value="30" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.7"},{"label": "30"},{"label": "用于控制 Iceberg 表 manifest 合并整理的新设置。"}]}]} />

通过 OPTIMIZE TABLE ... MANIFEST 触发仅针对 manifest 的合并整理所需的最少 manifest 文件数量。
如果当前 manifest 文件数量小于或等于该阈值，则会跳过合并整理。
需要启用 allow\_experimental\_iceberg\_compaction。

<div id="iceberg_max_number_datafiles_to_compact">
  ## iceberg\_max\_number\_datafiles\_to\_compact
</div>

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

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.5"},{"label": "1000"},{"label": "新增设置"}]}]} />

Iceberg 中参与合并整理的数据文件数量阈值。

<div id="iceberg_orphan_files_older_than_seconds">
  ## iceberg\_orphan\_files\_older\_than\_seconds
</div>

<ExperimentalBadge />

<SettingsInfoBlock type="UInt64" default_value="259200" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "26.4"},{"label": "259200"},{"label": "新增默认孤立文件期限阈值设置"}]}]} />

Iceberg 表中删除孤立文件时使用的默认文件期限阈值 (以秒为单位) 。新于该阈值的文件不会被视为孤立文件。当在 `remove_orphan_files()` 过程调用中省略 `older_than` 参数时，将使用此设置。默认值为 259200 (3 天) 。

<div id="iceberg_snapshot_id">
  ## iceberg\_snapshot\_id
</div>

<SettingsInfoBlock type="Int64" default_value="0" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "25.4"},{"label": "0"},{"label": "新增设置。"}]}]} />

使用指定的快照 ID 查询 Iceberg 表。

<div id="iceberg_timestamp_ms">
  ## iceberg\_timestamp\_ms
</div>

<SettingsInfoBlock type="Int64" default_value="0" />

<VersionHistory rows={[{"id": "row-1","items": [{"label": "25.4"},{"label": "0"},{"label": "新增设置。"}]}]} />

使用特定时间戳对应的快照查询 Iceberg 表。
