July 2023
Intermediate to advanced
278 pages
5h 40m
Chinese
Content preview from Trino 权威指南：原书第2版
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246
|
第
12
章
12.4
任务并发性
为了提高
Trino
集群的性能，你需要修改一些任务相关的属性的默认值。本节我们讨论
需要调整的两个常见属性，不过你还可以从
Trino
文档中找到一些其他可以调整的属性，
这些属性都在
config.properties
中进行设置。
Task worker threads
（任务工作线程数）
默认值是机器
CPU
数的
2
倍。例如，一台具有
2
个
6
核
CPU
的机器使用
2
×
6
×
2 = 24
个工作线程。如果你观察到所有的线程都在使用，但
CPU
使用率仍很低，则
可以尝试设置
task.max-worker-threads
属性来增加线程数，以此提高
CPU
利用
率和性能。建议尝试慢慢增加这个值，因为将其设置得过高会带来更高的内存使用
和额外的上下文切换成本，反而会带来负面效果。
Task operator concurrency
（任务算子并发数）
Join
和
Aggregation
等算子通过本地数据分区和并行执行算子来实现并行处理。
例如，数据先在本地根据
GROUP BY
的列进行分区，之后多个
Aggregation
算子
会并行地进行处理。这些并行操作的默认并发数是
16
，你可以通过设置
task.
concurrency
属性来调整它。如果你运行很多并发的查询，上下文切换的成本可能
会导致性能下降。对于只运行少量并发查询的集群，更高的并发数可以提高并行度
并因此提高性能。
12.5
工作节点调度
你可以通过调整某些调度相关属性的默认值来提高
Trino
集群的性能。通常有
3
个常见
的配置可以调整：
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O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.