August 2015
Intermediate to advanced
312 pages
7h 28m
Japanese
Content preview from 初めてのSpark
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.
89
5.3 ファイルシステム
ー
Hadoop
ー
Pure
Java
zlib
N
低速 中
org.apache.
hadoop.io.compress.
DefaultCodec
Y Y
Hadoop
のデフォ
ルトのコーデック。
Snappy
N
非常に
高速
低
org.apache.
hadoop.io.compress.
SnappyCodec
N Y
ポーティングされた
pure Java
の実装も
あるが、まだ
Spark/Hadoop
では利用できない。
Spark の
textFile()
メソッドは圧縮された入力を扱うことができるとはいえ、仮にスプリット可
能な形式になっているデータであっても
splittable
は自動的に無効化されてしまいます。大きな
単一ファイルの圧縮された入力データを読まなければならない場合は、Spark のラッパを通さず、
newAPIHadoopFile
もしくは
hadoopFile
を使い、適切な圧縮コーデックを指定してください。
入力フォーマットの中には、ルックアップの役に立つよう、キー／値データの中の値だけを圧
縮できるものがあります（例えば
SequenceFile
）。あるいは、独自の圧縮制御ができる入力フォー
マットもあります。例えば、
Twitter
の
Elephant Bird
パッケージ内のフォーマットの多くは、
LZO
で圧縮されたデータを扱うことができます。
5.3
フイルテム
Spark
は、多くのファイルシステムのデータを読み書きすることができます。それらのファイル ...
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.