March 2021
Intermediate to advanced
265 pages
6h 50m
Chinese
Content preview from Presto实战
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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.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.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.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.
20
｜
第
2
章
-Xmx4G
-XX:+UseG1GC
-XX:G1HeapRegionSize=32M
-XX:+UseGCOverheadLimit
-XX:+ExplicitGCInvokesConcurrent
-XX:+HeapDumpOnOutOfMemoryError
-XX:+ExitOnOutOfMemoryError
-Djdk.nio.maxCachedBufferSize=2000000
-Djdk.attach.allowAttachSelf=true
上述的配置文件就绪后，
Presto
就可以启动了。可以在第
5
章中找到这些配置文件更详细
的描述。
2.3
添加数据源
虽然已经安装好了
Presto
，但还不能就这样启动它。毕竟，你想要在
Presto
里查询一些外
部数据，这需要你将一个数据源配置为
catalog
。
Presto
的
catalog
定义了用户可用的数据源。数据访问是由
Presto
连接器执行的
，该连接器由
connector.name
属性在
catalog
中配置。
catalog
将数据源中的所有
schema
和表暴露给
Presto
。
例如，
Hive
连接器将每个
Hive
数据库映射到一个
schema
。如果想要使用
Hive
连接器将一
个名为
web
的
Hive
数据库（其中包含一张
clicks
表）暴露为名为
sitehive
的
catalog
，那
么我们需要在
catalog
文件中指定使用
Hive
连接器
。你可以使用完全限定名语法
catalog.
schema.table
来访问
catalog
，本例中就是
sitehive.web.clicks ...
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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.