> ## 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.

# backup_restore_* 会话设置

> ClickHouse 在 backup_restore_* 自动生成组中的会话设置。

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，由 [源文件](https://github.com/ClickHouse/ClickHouse/blob/master/src/Core/Settings.cpp) 自动生成。

<div id="backup_restore_batch_size_for_keeper_multi">
  ## backup\_restore\_batch\_size\_for\_keeper\_multi
</div>

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

备份或恢复期间，向 \[Zoo]Keeper 发送 multi request 时的批次最大大小

<div id="backup_restore_batch_size_for_keeper_multiread">
  ## backup\_restore\_batch\_size\_for\_keeper\_multiread
</div>

<SettingsInfoBlock type="UInt64" default_value="10000" />

在备份或恢复期间，向 \[Zoo]Keeper 发起 multiread 读取请求时的最大批次大小

<div id="backup_restore_failure_after_host_disconnected_for_seconds">
  ## backup\_restore\_failure\_after\_host\_disconnected\_for\_seconds
</div>

<SettingsInfoBlock type="UInt64" default_value="3600" />

如果某个主机在执行 BACKUP ON CLUSTER 或 RESTORE ON CLUSTER 操作期间，在这段时间内未能在 ZooKeeper 中重新创建其临时 'alive' 节点，则整个备份或恢复都会被视为失败。
该值应大于主机发生故障后重新连接到 ZooKeeper 所需的任何合理时长。
零表示无限制。

<div id="backup_restore_finish_timeout_after_error_sec">
  ## backup\_restore\_finish\_timeout\_after\_error\_sec
</div>

<SettingsInfoBlock type="UInt64" default_value="180" />

在当前 BACKUP ON CLUSTER 或 RESTORE ON CLUSTER 操作中，“发起”节点在出现“error”节点后，等待其他主机作出响应并停止当前工作的时长。

<div id="backup_restore_keeper_fault_injection_probability">
  ## backup\_restore\_keeper\_fault\_injection\_probability
</div>

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

在备份或恢复期间，Keeper 请求发生故障的近似概率。有效值范围为 \[0.0f, 1.0f]

<div id="backup_restore_keeper_fault_injection_seed">
  ## backup\_restore\_keeper\_fault\_injection\_seed
</div>

<SettingsInfoBlock type="UInt64" default_value="0" />

0 - 使用随机种子，否则使用该设置值

<div id="backup_restore_keeper_max_retries">
  ## backup\_restore\_keeper\_max\_retries
</div>

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

BACKUP 或 RESTORE 操作期间，\[Zoo]Keeper 操作的最大重试次数。
该值应足够大，以避免整个操作因临时的 \[Zoo]Keeper 故障而失败。

<div id="backup_restore_keeper_max_retries_while_handling_error">
  ## backup\_restore\_keeper\_max\_retries\_while\_handling\_error
</div>

<SettingsInfoBlock type="UInt64" default_value="20" />

处理 BACKUP ON CLUSTER 或 RESTORE ON CLUSTER 操作错误时，\[Zoo]Keeper 操作的最大重试次数。

<div id="backup_restore_keeper_max_retries_while_initializing">
  ## backup\_restore\_keeper\_max\_retries\_while\_initializing
</div>

<SettingsInfoBlock type="UInt64" default_value="20" />

初始化 BACKUP ON CLUSTER 或 RESTORE ON CLUSTER 操作时，\[Zoo]Keeper 操作的最大重试次数。

<div id="backup_restore_keeper_retry_initial_backoff_ms">
  ## backup\_restore\_keeper\_retry\_initial\_backoff\_ms
</div>

<SettingsInfoBlock type="UInt64" default_value="100" />

备份或恢复期间 \[Zoo]Keeper 操作的初始退避超时时间

<div id="backup_restore_keeper_retry_max_backoff_ms">
  ## backup\_restore\_keeper\_retry\_max\_backoff\_ms
</div>

<SettingsInfoBlock type="UInt64" default_value="5000" />

在备份或恢复期间，\[Zoo]Keeper 操作的最大退避超时时间

Cloud 默认值：`60000`。

<div id="backup_restore_keeper_value_max_size">
  ## backup\_restore\_keeper\_value\_max\_size
</div>

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

备份期间 \[Zoo]Keeper 节点数据的最大大小

<div id="backup_restore_s3_retry_attempts">
  ## backup\_restore\_s3\_retry\_attempts
</div>

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

Aws::Client::RetryStrategy 的设置项。Aws::Client 会自行执行重试；0 表示不重试。仅用于备份/恢复。

<div id="backup_restore_s3_retry_initial_backoff_ms">
  ## backup\_restore\_s3\_retry\_initial\_backoff\_ms
</div>

<SettingsInfoBlock type="UInt64" default_value="25" />

在备份和恢复期间，首次重试前的初始退避延迟，单位为毫秒。此后的每次重试都会按指数方式增加延迟，最大值由 `backup_restore_s3_retry_max_backoff_ms` 指定

<div id="backup_restore_s3_retry_jitter_factor">
  ## backup\_restore\_s3\_retry\_jitter\_factor
</div>

<SettingsInfoBlock type="Float" default_value="0.1" />

在备份和恢复操作期间，应用于 Aws::Client::RetryStrategy 中重试退避延迟的抖动因子。计算出的退避延迟会乘以一个位于 \[1.0, 1.0 + jitter] 范围内的随机因子，最大不超过 `backup_restore_s3_retry_max_backoff_ms`。必须位于 \[0.0, 1.0] 区间内

<div id="backup_restore_s3_retry_max_backoff_ms">
  ## backup\_restore\_s3\_retry\_max\_backoff\_ms
</div>

<SettingsInfoBlock type="UInt64" default_value="5000" />

备份和恢复操作期间，重试之间的最大延迟 (毫秒) 。