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

> QUOTA 文档

# CREATE QUOTA

创建可分配给用户或角色的[配额](/zh/concepts/features/security/access-rights#quotas-management)。

语法：

```sql theme={null}
CREATE QUOTA [IF NOT EXISTS | OR REPLACE] name [ON CLUSTER cluster_name]
    [IN access_storage_type]
    [KEYED BY {user_name | ip_address | client_key | client_key,user_name | client_key,ip_address | normalized_query_hash} | NOT KEYED]
    [FOR [RANDOMIZED] INTERVAL number {second | minute | hour | day | week | month | quarter | year}
        {MAX { {queries | query_selects | query_inserts | errors | result_rows | result_bytes | read_rows | read_bytes | written_bytes | execution_time | failed_sequential_authentications | queries_per_normalized_hash} = number } [,...] |
         NO LIMITS | TRACKING ONLY} [,...]]
    [TO {role [,...] | ALL | ALL EXCEPT role [,...]}]
```

键 `user_name`、`ip_address`、`client_key`、`client_key, user_name`、`client_key, ip_address` 和 `normalized_query_hash` 与 [system.quotas](/zh/reference/system-tables/quotas) 表中的字段对应。

参数 `queries`、`query_selects`、`query_inserts`、`errors`、`result_rows`、`result_bytes`、`read_rows`、`read_bytes`、`written_bytes`、`execution_time`、`failed_sequential_authentications`、`queries_per_normalized_hash` 与 [system.quotas\_usage](/zh/reference/system-tables/quotas_usage) 表中的字段对应。

`ON CLUSTER` 子句允许在集群上创建配额，参见 [分布式 DDL](/zh/reference/statements/distributed-ddl)。

**示例**

将当前用户在 15 个月内的最大查询次数限制为 123 次：

```sql theme={null}
CREATE QUOTA qA FOR INTERVAL 15 month MAX queries = 123 TO CURRENT_USER;
```

对于默认用户，将 30 分钟内的最大执行时间限制为半秒，并将最大查询数限制为 321，5 个季度内允许的最大错误数限制为 10：

```sql theme={null}
CREATE QUOTA qB FOR INTERVAL 30 minute MAX execution_time = 0.5, FOR INTERVAL 5 quarter MAX queries = 321, errors = 10 TO default;
```

创建一个 QUOTA，为每个不同的归一化查询模式分配单独的 bucket，并将其执行次数限制为每小时 100 次：

```sql theme={null}
CREATE QUOTA qC KEYED BY normalized_query_hash FOR INTERVAL 1 hour MAX queries = 100 TO default;
```

将任一归一化查询模式限制为每小时最多执行 50 次 (无论 QUOTA 键类型为何) ：

```sql theme={null}
CREATE QUOTA qD FOR INTERVAL 1 hour MAX queries_per_normalized_hash = 50 TO default;
```

更多使用 xml 配置的示例 (ClickHouse Cloud 不支持) 可参见[配额指南](/zh/concepts/features/configuration/server-config/quotas)。

<div id="related-content">
  ## 相关内容
</div>

* 博客：[使用 ClickHouse 构建单页应用](https://clickhouse.com/blog/building-single-page-applications-with-clickhouse-and-http)