> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-mintlify-8a08bda2.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

> 包含有关服务器全局设置的系统表， 这些设置在 `config.xml` 中指定。

# system.server_settings

<Info>
  **在 ClickHouse Cloud 中查询**

  此系统表中的数据分别保存在 ClickHouse Cloud 各节点的本地。因此，如需查看所有数据的完整情况，需要使用 `clusterAllReplicas` 函数。更多详情请参见[此处](/zh/reference/system-tables/overview#system-tables-in-clickhouse-cloud)。
</Info>

<div id="description">
  ## 说明
</div>

包含在 `config.xml` 中指定的服务器全局设置相关信息。
目前，该表仅显示 `config.xml` 第一层的设置，尚不支持嵌套配置 (例如 [logger](/zh/reference/settings/server-settings/settings#logger)) 。

<div id="columns">
  ## 列
</div>

* `name` ([String](/zh/reference/data-types)) — 服务器设置名称。
* `value` ([String](/zh/reference/data-types)) — 服务器设置值。
* `default` ([String](/zh/reference/data-types)) — 服务器设置默认值。
* `changed` ([UInt8](/zh/reference/data-types)) — 显示该设置是否在 config.xml 中指定。
* `description` ([String](/zh/reference/data-types)) — 服务器设置的简要说明。
* `type` ([String](/zh/reference/data-types)) — 服务器设置值的类型。
* `changeable_without_restart` ([Enum8('No' = 0, 'IncreaseOnly' = 1, 'DecreaseOnly' = 2, 'Yes' = 3)](/zh/reference/data-types)) — 显示该设置是否可在运行时更改。
* `is_obsolete` ([UInt8](/zh/reference/data-types)) — 显示该设置是否已废弃。

<div id="example">
  ## 示例
</div>

以下示例说明如何获取名称中包含 `thread_pool` 的服务器设置相关信息。

```sql theme={null}
SELECT *
FROM system.server_settings
WHERE name LIKE '%thread_pool%'
```

```text theme={null}
┌─name──────────────────────────────────────────┬─value─┬─default─┬─changed─┬─description─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬─type───┬─changeable_without_restart─┬─is_obsolete─┐
│ max_thread_pool_size                          │ 10000 │ 10000   │       0 │ The maximum number of threads that could be allocated from the OS and used for query execution and background operations.                           │ UInt64 │                         No │           0 │
│ max_thread_pool_free_size                     │ 1000  │ 1000    │       0 │ The maximum number of threads that will always stay in a global thread pool once allocated and remain idle in case of insufficient number of tasks. │ UInt64 │                         No │           0 │
│ thread_pool_queue_size                        │ 10000 │ 10000   │       0 │ The maximum number of tasks that will be placed in a queue and wait for execution.                                                                  │ UInt64 │                         No │           0 │
│ max_io_thread_pool_size                       │ 100   │ 100     │       0 │ The maximum number of threads that would be used for IO operations                                                                                  │ UInt64 │                         No │           0 │
│ max_io_thread_pool_free_size                  │ 0     │ 0       │       0 │ Max free size for IO thread pool.                                                                                                                   │ UInt64 │                         No │           0 │
│ io_thread_pool_queue_size                     │ 10000 │ 10000   │       0 │ Queue size for IO thread pool.                                                                                                                      │ UInt64 │                         No │           0 │
│ max_active_parts_loading_thread_pool_size     │ 64    │ 64      │       0 │ The number of threads to load active set of data parts (Active ones) at startup.                                                                    │ UInt64 │                         No │           0 │
│ max_outdated_parts_loading_thread_pool_size   │ 32    │ 32      │       0 │ The number of threads to load inactive set of data parts (Outdated ones) at startup.                                                                │ UInt64 │                         No │           0 │
│ max_unexpected_parts_loading_thread_pool_size │ 32    │ 32      │       0 │ The number of threads to load inactive set of data parts (Unexpected ones) at startup.                                                              │ UInt64 │                         No │           0 │
│ max_parts_cleaning_thread_pool_size           │ 128   │ 128     │       0 │ The number of threads for concurrent removal of inactive data parts.                                                                                │ UInt64 │                         No │           0 │
│ max_backups_io_thread_pool_size               │ 1000  │ 1000    │       0 │ The maximum number of threads that would be used for IO operations for BACKUP queries                                                               │ UInt64 │                         No │           0 │
│ max_backups_io_thread_pool_free_size          │ 0     │ 0       │       0 │ Max free size for backups IO thread pool.                                                                                                           │ UInt64 │                         No │           0 │
│ backups_io_thread_pool_queue_size             │ 0     │ 0       │       0 │ Queue size for backups IO thread pool.                                                                                                              │ UInt64 │                         No │           0 │
└───────────────────────────────────────────────┴───────┴─────────┴─────────┴─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴────────┴────────────────────────────┴─────────────┘

```

使用 `WHERE changed` 很有用，例如，当你想检查配置文件中的设置是否已正确加载并生效时。

```sql theme={null}
SELECT * FROM system.server_settings WHERE changed AND name='max_thread_pool_size'
```

<div id="see-also">
  ## 另请参阅
</div>

* [设置](/zh/reference/system-tables/settings)
* [配置文件](/zh/concepts/features/configuration/server-config/configuration-files)
* [服务器设置](/zh/reference/settings/server-settings/settings)