November 2017
Intermediate to advanced
328 pages
6h 51m
Japanese
Content preview from 入門 PySpark ―PythonとJupyterで活用するSpark 2エコシステム
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
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.
2.4
変換
23
かねません。この場合、Sparkがクラスタ上でどのようにコードを実行するのかを理解する必要があり
ます。
クラスタモードでは、ジョブが投入されて実行されるとき、そのジョブはドライバノード（もしくは
マスターノード）に送られます。ドライバノードはそのジョブの DAG（「 1 章 Spark を理解する」参照）
を生成し、それぞれのタスクを実行するエクゼキュータ（あるいはワーカー）ノードを決定します。
そしてドライバは、ワーカーに対してそれぞれのタスクを実行し、処理が終われば結果をドライバに
返すように指示します。ただしその前に、ドライバはそれぞれのタスクのクロージャを準備します。ク
ロージャはドライバ上にあるメソッドや変数の集合で、ワーカーが RDDに対してタスクを実行するた
めのものです。
この変数とメソッドの集合は、エクゼキュータの動作環境の中では本来的に静的なものです。すなわ
ち、それぞれのエクゼキュータがドライバから受け取るのはこの変数とメソッドのコピーであり、仮に
タスクの実行時にエクゼキュータがこれらの変数を書き換えたり、メソッドを上書きしたりしても、そ
れが他のエクゼキュータのコピーやドライバの変数やメソッドに影響することはありません。このため
に挙動が予想外のものになったり、しばしばきわめて追跡が難しい実行時のバグが生じたりすることに
なります。
次の
PySpark
のドキュメンテーションにはさらに多くの実際的な例があるので、調べてみて
ください（
http://spark.apa ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
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.