August 2015
Intermediate to advanced
312 pages
7h 28m
Japanese
Content preview from 初めてのSpark
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184
9 章 Spark SQL
最後に、
Beeline
を使えば、クエリの実行計画も簡単に見ることができます。
9-35
に示
す通り、
EXPLAIN
を任意のクエリに対して実行すれば、その実行計画がどうなるかを見ることがで
きます。
9-35
Spark SQL
EXPLAIN
spark-sql> EXPLAIN SELECT * FROM mytable where key = 1;
== Physical Plan ==
Filter (key#16 = 1)
HiveTableScan [key#16,value#17], (MetastoreRelation default, mytable, None), None
Time taken: 0.551 seconds
このクエリの実行計画では、
Spark SQL
は
HiveTableScan
の結果にフィルタを適用しようとし
ています。
Beeline
からは、データに対するクエリを行うための
SQL
を書くこともできます。
Beeline
シェルは、キャッシュされ、複数のユーザーによって共有されたテーブル内のデータをす
ばやく探索するのに最適です。
9.4.2
間するテールク
Spark SQL
の
JDBC
サーバーを使うメリットの
1
つは、キャッシュされたテーブルを複数のプ
ログラム間で共有できることです。これは、
JDBC Thrift
サーバーが
1
つのドライバプログラムに
なっていることによります。前セクションで見た通り、テーブルを共有するのに必要なのは、テー ...
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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.