ClickHouse/docs/zh/sql-reference/statements/system.md
Ivan Blinkov cd14f9ebcb
SQL reference refactoring (#10857)
* split up select.md

* array-join.md basic refactoring

* distinct.md basic refactoring

* format.md basic refactoring

* from.md basic refactoring

* group-by.md basic refactoring

* having.md basic refactoring

* additional index.md refactoring

* into-outfile.md basic refactoring

* join.md basic refactoring

* limit.md basic refactoring

* limit-by.md basic refactoring

* order-by.md basic refactoring

* prewhere.md basic refactoring

* adjust operators/index.md links

* adjust sample.md links

* adjust more links

* adjust operatots links

* fix some links

* adjust aggregate function article titles

* basic refactor of remaining select clauses

* absolute paths in make_links.sh

* run make_links.sh

* remove old select.md locations

* translate docs/es

* translate docs/fr

* translate docs/fa

* remove old operators.md location

* change operators.md links

* adjust links in docs/es

* adjust links in docs/es

* minor texts adjustments

* wip

* update machine translations to use new links

* fix changelog

* es build fixes

* get rid of some select.md links

* temporary adjust ru links

* temporary adjust more ru links

* improve curly brace handling

* adjust ru as well

* fa build fix

* ru link fixes

* zh link fixes

* temporary disable part of anchor checks
2020-05-15 07:34:54 +03:00

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---
machine_translated: true
machine_translated_rev: 72537a2d527c63c07aa5d2361a8829f3895cf2bd
toc_priority: 37
toc_title: SYSTEM
---
# 系统查询 {#query-language-system}
- [RELOAD DICTIONARIES](#query_language-system-reload-dictionaries)
- [RELOAD DICTIONARY](#query_language-system-reload-dictionary)
- [DROP DNS CACHE](#query_language-system-drop-dns-cache)
- [DROP MARK CACHE](#query_language-system-drop-mark-cache)
- [FLUSH LOGS](#query_language-system-flush_logs)
- [RELOAD CONFIG](#query_language-system-reload-config)
- [SHUTDOWN](#query_language-system-shutdown)
- [KILL](#query_language-system-kill)
- [STOP DISTRIBUTED SENDS](#query_language-system-stop-distributed-sends)
- [FLUSH DISTRIBUTED](#query_language-system-flush-distributed)
- [START DISTRIBUTED SENDS](#query_language-system-start-distributed-sends)
- [STOP MERGES](#query_language-system-stop-merges)
- [START MERGES](#query_language-system-start-merges)
## RELOAD DICTIONARIES {#query_language-system-reload-dictionaries}
重新加载之前已成功加载的所有字典。
默认情况下,字典是懒惰加载的(请参阅 [dictionaries\_lazy\_load](../../operations/server-configuration-parameters/settings.md#server_configuration_parameters-dictionaries_lazy_load)所以不是在启动时自动加载而是通过dictGet函数在第一次访问时初始化或者从ENGINE=Dictionary的表中选择。 该 `SYSTEM RELOAD DICTIONARIES` 查询重新加载这样的字典(加载)。
总是返回 `Ok.` 无论字典更新的结果如何。
## 重新加载字典Dictionary\_name {#query_language-system-reload-dictionary}
完全重新加载字典 `dictionary_name`与字典的状态无关LOADED/NOT\_LOADED/FAILED
总是返回 `Ok.` 无论更新字典的结果如何。
字典的状态可以通过查询 `system.dictionaries` 桌子
``` sql
SELECT name, status FROM system.dictionaries;
```
## DROP DNS CACHE {#query_language-system-drop-dns-cache}
重置ClickHouse的内部DNS缓存。 有时对于旧的ClickHouse版本在更改基础架构更改另一个ClickHouse服务器或字典使用的服务器的IP地址时需要使用此命令。
有关更方便自动缓存管理请参阅disable\_internal\_dns\_cache、dns\_cache\_update\_period参数。
## DROP MARK CACHE {#query_language-system-drop-mark-cache}
重置标记缓存。 用于开发ClickHouse和性能测试。
## FLUSH LOGS {#query_language-system-flush_logs}
Flushes buffers of log messages to system tables (e.g. system.query\_log). Allows you to not wait 7.5 seconds when debugging.
## RELOAD CONFIG {#query_language-system-reload-config}
重新加载ClickHouse配置。 当配置存储在ZooKeeeper中时使用。
## SHUTDOWN {#query_language-system-shutdown}
通常关闭ClickHouse如 `service clickhouse-server stop` / `kill {$pid_clickhouse-server}`)
## KILL {#query_language-system-kill}
中止ClickHouse进程如 `kill -9 {$ pid_clickhouse-server}`)
## 管理分布式表 {#query-language-system-distributed}
ClickHouse可以管理 [分布](../../engines/table-engines/special/distributed.md) 桌子 当用户将数据插入到这些表中时ClickHouse首先创建应发送到群集节点的数据队列然后异步发送它。 您可以使用 [STOP DISTRIBUTED SENDS](#query_language-system-stop-distributed-sends), [FLUSH DISTRIBUTED](#query_language-system-flush-distributed),和 [START DISTRIBUTED SENDS](#query_language-system-start-distributed-sends) 查询。 您也可以同步插入分布式数据与 `insert_distributed_sync` 设置。
### STOP DISTRIBUTED SENDS {#query_language-system-stop-distributed-sends}
将数据插入分布式表时禁用后台数据分发。
``` sql
SYSTEM STOP DISTRIBUTED SENDS [db.]<distributed_table_name>
```
### FLUSH DISTRIBUTED {#query_language-system-flush-distributed}
强制ClickHouse将数据同步发送到群集节点。 如果任何节点不可用ClickHouse将引发异常并停止查询执行。 您可以重试查询,直到查询成功,这将在所有节点恢复联机时发生。
``` sql
SYSTEM FLUSH DISTRIBUTED [db.]<distributed_table_name>
```
### START DISTRIBUTED SENDS {#query_language-system-start-distributed-sends}
将数据插入分布式表时启用后台数据分发。
``` sql
SYSTEM START DISTRIBUTED SENDS [db.]<distributed_table_name>
```
### STOP MERGES {#query_language-system-stop-merges}
提供停止MergeTree系列中表的后台合并的可能性:
``` sql
SYSTEM STOP MERGES [[db.]merge_tree_family_table_name]
```
!!! note "注"
`DETACH / ATTACH` 即使在之前所有MergeTree表的合并已停止的情况下table也会为表启动后台合并。
### START MERGES {#query_language-system-start-merges}
为MergeTree系列中的表提供启动后台合并的可能性:
``` sql
SYSTEM START MERGES [[db.]merge_tree_family_table_name]
```
[原始文章](https://clickhouse.tech/docs/en/query_language/system/) <!--hide-->