mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-29 19:12:03 +00:00
56 lines
4.6 KiB
Markdown
56 lines
4.6 KiB
Markdown
---
|
|
machine_translated: true
|
|
machine_translated_rev: 5decc73b5dc60054f19087d3690c4eb99446a6c3
|
|
---
|
|
|
|
# 系统。设置 {#system-tables-system-settings}
|
|
|
|
包含有关当前用户的会话设置的信息。
|
|
|
|
列:
|
|
|
|
- `name` ([字符串](../../sql-reference/data-types/string.md)) — Setting name.
|
|
- `value` ([字符串](../../sql-reference/data-types/string.md)) — Setting value.
|
|
- `changed` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows whether a setting is changed from its default value.
|
|
- `description` ([字符串](../../sql-reference/data-types/string.md)) — Short setting description.
|
|
- `min` ([可为空](../../sql-reference/data-types/nullable.md)([字符串](../../sql-reference/data-types/string.md))) — Minimum value of the setting, if any is set via [制约因素](../../operations/settings/constraints-on-settings.md#constraints-on-settings). 如果设置没有最小值，则包含 [NULL](../../sql-reference/syntax.md#null-literal).
|
|
- `max` ([可为空](../../sql-reference/data-types/nullable.md)([字符串](../../sql-reference/data-types/string.md))) — Maximum value of the setting, if any is set via [制约因素](../../operations/settings/constraints-on-settings.md#constraints-on-settings). 如果设置没有最大值，则包含 [NULL](../../sql-reference/syntax.md#null-literal).
|
|
- `readonly` ([UInt8](../../sql-reference/data-types/int-uint.md#uint-ranges)) — Shows whether the current user can change the setting:
|
|
- `0` — Current user can change the setting.
|
|
- `1` — Current user can't change the setting.
|
|
|
|
**示例**
|
|
|
|
下面的示例演示如何获取有关名称包含的设置的信息 `min_i`.
|
|
|
|
``` sql
|
|
SELECT *
|
|
FROM system.settings
|
|
WHERE name LIKE '%min_i%'
|
|
```
|
|
|
|
``` text
|
|
┌─name────────────────────────────────────────┬─value─────┬─changed─┬─description───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┬─min──┬─max──┬─readonly─┐
|
|
│ min_insert_block_size_rows │ 1048576 │ 0 │ Squash blocks passed to INSERT query to specified size in rows, if blocks are not big enough. │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │
|
|
│ min_insert_block_size_bytes │ 268435456 │ 0 │ Squash blocks passed to INSERT query to specified size in bytes, if blocks are not big enough. │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │
|
|
│ read_backoff_min_interval_between_events_ms │ 1000 │ 0 │ Settings to reduce the number of threads in case of slow reads. Do not pay attention to the event, if the previous one has passed less than a certain amount of time. │ ᴺᵁᴸᴸ │ ᴺᵁᴸᴸ │ 0 │
|
|
└─────────────────────────────────────────────┴───────────┴─────────┴───────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┴──────┴──────┴──────────┘
|
|
```
|
|
|
|
使用 `WHERE changed` 可以是有用的，例如，当你想检查:
|
|
|
|
- 配置文件中的设置是否正确加载并正在使用。
|
|
- 在当前会话中更改的设置。
|
|
|
|
<!-- -->
|
|
|
|
``` sql
|
|
SELECT * FROM system.settings WHERE changed AND name='load_balancing'
|
|
```
|
|
|
|
**另请参阅**
|
|
|
|
- [设置](../../operations/settings/index.md#session-settings-intro)
|
|
- [查询权限](../../operations/settings/permissions-for-queries.md#settings_readonly)
|
|
- [对设置的限制](../../operations/settings/constraints-on-settings.md)
|