mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-01 12:01:58 +00:00
60 lines
1.4 KiB
Markdown
60 lines
1.4 KiB
Markdown
---
|
|
slug: /zh/sql-reference/statements/alter/setting
|
|
sidebar_position: 38
|
|
sidebar_label: SETTING
|
|
---
|
|
|
|
# 表设置操作 {#table_settings_manipulations}
|
|
|
|
这是一组更改表设置的操作。你可以修改设置或将其重置为默认值。单个查询可以同时更改多个设置。 如果指定名称的设置不存在，则查询会引发异常。
|
|
|
|
**语法**
|
|
|
|
``` sql
|
|
ALTER TABLE [db].name [ON CLUSTER cluster] MODIFY|RESET SETTING ...
|
|
```
|
|
|
|
:::note
|
|
这些查询只能应用于 [MergeTree](../../../engines/table-engines/mergetree-family/mergetree.md) 表。
|
|
:::
|
|
|
|
|
|
## 修改设置 {#alter_modify_setting}
|
|
|
|
更改表设置
|
|
|
|
**语法**
|
|
|
|
```sql
|
|
MODIFY SETTING setting_name=value [, ...]
|
|
```
|
|
|
|
**示例**
|
|
|
|
```sql
|
|
CREATE TABLE example_table (id UInt32, data String) ENGINE=MergeTree() ORDER BY id;
|
|
ALTER TABLE example_table MODIFY SETTING max_part_loading_threads=8, max_parts_in_total=50000;
|
|
```
|
|
|
|
## 重置设置 {#alter_reset_setting}
|
|
|
|
重置表设置为默认值。如果设置处于默认状态，则不采取任何操作。
|
|
|
|
**语法**
|
|
|
|
```sql
|
|
RESET SETTING setting_name [, ...]
|
|
```
|
|
|
|
**示例**
|
|
|
|
```sql
|
|
CREATE TABLE example_table (id UInt32, data String) ENGINE=MergeTree() ORDER BY id
|
|
SETTINGS max_part_loading_threads=8;
|
|
ALTER TABLE example_table RESET SETTING max_part_loading_threads;
|
|
```
|
|
|
|
**参见**
|
|
|
|
- [MergeTree settings](../../../operations/settings/merge-tree-settings.mdx)
|