压测clickhouse性能相关参数

背景:压测ck性能一直上不去,但是ck负载不大。尝试调整参数,验证是否有性能提升

1、background_common_pool_size

Sets the number of threads performing background non-specialized operations like cleaning the filesystem etc. for tables with MergeTree engines. Could be increased at runtime and could be applied at server startup from the default profile for backward compatibility.

2 、 max_threads 验证有效

The maximum number of threads to execute the request. By default, it is determined automatically.

3、background_pool_size

Sets the number of threads performing background merges and mutations for tables with MergeTree engines. You can only increase the number of threads at runtime. To lower the number of threads you have to restart the server. By adjusting this setting, you manage CPU and disk load. Smaller pool size utilizes less CPU and disk resources, but background processes advance slower which might eventually impact query performance.

Before changing it, please also take a look at related MergeTree settings, such as number_of_free_entries_in_pool_to_lower_max_size_of_merge and number_of_free_entries_in_pool_to_execute_mutation.

查看参数;

bash 复制代码
select * from system.settings where name  like '%background_common_pool_size%'
bash 复制代码
SHOW [CHANGED] SETTINGS LIKE|ILIKE <name>

show settings like '%background_common_pool_size%'

4、设置参数

bash 复制代码
SET param = value
set  background_common_pool_size = 128

加个globa执行也没报错 官方文档上没有global参数。但是阿里云dms 需要加上global 才能全局生效

bash 复制代码
set global background_common_pool_size = 128

https://help.aliyun.com/zh/clickhouse/user-guide/set-parameters-in-the-user-xml-file?spm=a2c4g.11186623.0.0.6bdc5d7fnAdCqs

https://clickhouse.com/docs/zh/sql-reference/statements/set

如果更改配置文件config以后

查询system.settings里面的参数没生效时因为

这里没改是因为system.settings查询的时候值是从user.xml中获取的,所以一直都原来的值,其实生效的是在config.xml里

https://clickhouse.com/docs/en/operations/server-configuration-parameters/settings#background_pool_size

https://blog.csdn.net/qq_35423190/article/details/109999576

相关推荐
言之。3 天前
简单介绍一下Clickhouse及其引擎
clickhouse
西京刀客3 天前
clickhouse的UInt64类型(countIf() 函数返回)
clickhouse·uint64·countif
Super_King_4 天前
ClickHouse 中 ORDER BY 场景下 arrayExists 与 hasAny 性能深入研究:布隆过滤器索引的影响分析
clickhouse
Super_King_4 天前
深入研究:ClickHouse中arrayExists与hasAny在ORDER BY场景下的性能差异
clickhouse
-KamMinG4 天前
阿里云ClickHouse数据保护秘籍:本地备份与恢复详解
clickhouse·阿里云·云计算
问道飞鱼4 天前
【大数据相关】ClickHouse命令行与SQL语法详解
大数据·sql·clickhouse
MMMMMMMMMMemory9 天前
clickhouse迁移工具clickhouse-copier
clickhouse
securitor9 天前
【clickhouse】设置密码
clickhouse
天道有情战天下12 天前
ClickHouse使用Docker部署
clickhouse·docker·容器