August 2015
Intermediate to advanced
312 pages
7h 28m
Japanese
Content preview from 初めてのSpark
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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.
133
7.5 Spark アプリケーション内および Spark アプリケーション間でのスケジューリング
7.4.3
の
時折困った問題になるのは、ユーザーのアプリケーションと
Spark
そのものがどちらも同じ
ライブラリに依存している場合に生ずる、依存性の衝突への対処です。この問題が生ずるのは比
較的珍しいことですが、生じた場合にはユーザーにとってやっかいなことになります。通常の場
合、この問題は
Spark
のジョブの実行の際のクラスのロードに関連して、
NoSuchMethodError
や
ClassNotFoundException
、あるいはその他の
JVM
の例外が生ずるといった形で表面化します。こ
の問題への対処方法は
2
つあります。
1
つ目は、ユーザーがアプリケーションを修正して、依存対
象のサードパーティのライブラリのバージョンを、
Spark
と合わせることです。
2
つ目の方法は、
しばしば「シェーディング」と呼ばれる手順を使って、アプリケーションのパッケージングを修正
することです。ビルドツールの
Maven
は、
7-5
のようなプラグインの高度な設定によって
シェーディングをサポートしています（実際には、このプラグインが
maven-shade-plugin
という
名前になっているのは、このシェーディングの機能があるためです）。シェーディングを行うこと
で、別の名前空間の中に衝突を起こしたパッケージの第
2
のコピーを置き、アプリケーションの
コードを書き換え、名前空間を変更した方のバージョンを使うようにすることができます。これは ...
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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.