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.
170
9 章 Spark SQL
注意しなければならないのは、既存の
Hive
の動作環境がない場合、
Spark SQL
は
Hive
のメタ
ストア（メタデータのデータベース）をプログラムの作業ディレクトリに、
metastore_db
という
名前で独自に作成することです。加えて、
HiveQL
の
CREATE TABLE
文を使ってテーブルを作成し
ようとした場合（
CREATE EXTERNAL TABLE
を使った場合は別です）、作成されるテーブルはデフォ
ルトのファイルシステム（これはローカルのファイルシステムの場合もあれば、クラスパス上に
hdfs-site.xml
があれば
HDFS
の場合もあります）の
/user/hive/warehouse
ディレクトリに作成
されます。
9.2
アーンの
Spark SQL
の
Spark SQL
を使う最も強力な方法は、
Spark
のアプリケーション内で使う方法です。そうする
ことで、データのロードやクエリを
SQL
で容易に行いながら、同時にそういった機能を
Python
や
Java
、
Scala
で書かれた通常のプログラムコードと組み合わせることができます。
Spark SQL
をこの方法で使うには、
SparkContext
を元にして、
HiveContext
（あるいは縮小版
を使いたい場合は
SQLContext
）を構築します。この
HiveContext
は、
Spark SQL
のデータに対
するクエリや操作のための追加の関数を提供します。
HiveContext
を使うことで、構造化データを ...
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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.