Apache Spark - A unified analytics engine for large-scale data processing
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Reynold Xin dcaa016610 [SPARK-13897][SQL] RelationalGroupedDataset and KeyValueGroupedDataset
## What changes were proposed in this pull request?
Previously, Dataset.groupBy returns a GroupedData, and Dataset.groupByKey returns a GroupedDataset. The naming is very similar, and unfortunately does not convey the real differences between the two.

Assume we are grouping by some keys (K). groupByKey is a key-value style group by, in which the schema of the returned dataset is a tuple of just two fields: key and value. groupBy, on the other hand, is a relational style group by, in which the schema of the returned dataset is flattened and contain |K| + |V| fields.

This pull request also removes the experimental tag from RelationalGroupedDataset. It has been with DataFrame since 1.3, and we have enough confidence now to stabilize it.

## How was this patch tested?
This is a rename to improve API understandability. Should be covered by all existing tests.

Author: Reynold Xin <rxin@databricks.com>

Closes #11841 from rxin/SPARK-13897.
2016-03-19 11:23:14 -07:00
.github [MINOR][MAINTENANCE] Fix typo for the pull request template. 2016-02-24 00:45:31 -08:00
assembly [SPARK-6363][BUILD] Make Scala 2.11 the default Scala version 2016-01-30 00:20:28 -08:00
bin [SPARK-13576][BUILD] Don't create assembly for examples. 2016-03-15 09:44:51 -07:00
build [SPARK-13324][CORE][BUILD] Update plugin, test, example dependencies for 2.x 2016-02-17 19:03:29 -08:00
common [SPARK-13921] Store serialized blocks as multiple chunks in MemoryStore 2016-03-17 20:00:56 -07:00
conf [SPARK-13264][DOC] Removed multi-byte characters in spark-env.sh.template 2016-02-11 09:30:36 +00:00
core [SPARK-13958] Executor OOM due to unbounded growth of pointer array in… 2016-03-18 12:56:06 -07:00
data [SPARK-13013][DOCS] Replace example code in mllib-clustering.md using include_example 2016-03-03 09:32:47 -08:00
dev [SPARK-13948] MiMa check should catch if the visibility changes to private 2016-03-16 23:02:25 -07:00
docs [MINOR][DOCS] Update build descriptions and commands 2016-03-18 21:32:48 -07:00
examples [MINOR][DOC] Fix nits in JavaStreamingTestExample 2016-03-18 12:34:14 +00:00
external [SPARK-13928] Move org.apache.spark.Logging into org.apache.spark.internal.Logging 2016-03-17 19:23:38 +08:00
graphx [SPARK-13928] Move org.apache.spark.Logging into org.apache.spark.internal.Logging 2016-03-17 19:23:38 +08:00
launcher [SPARK-13823][HOTFIX] Increase tryAcquire timeout and assert it succeeds to fix failure on slow machines 2016-03-16 16:11:24 +00:00
licenses [SPARK-10833] [BUILD] Inline, organize BSD/MIT licenses in LICENSE 2015-09-28 22:56:43 -04:00
mllib [SPARK-13629][ML] Add binary toggle Param to CountVectorizer 2016-03-18 17:34:33 -07:00
project [SPARK-13897][SQL] RelationalGroupedDataset and KeyValueGroupedDataset 2016-03-19 11:23:14 -07:00
python [SPARK-13937][PYSPARK][ML] Change JavaWrapper _java_obj from static to member variable 2016-03-17 10:16:51 -07:00
R [MINOR][DOCS] Use spark-submit instead of sparkR to submit R script. 2016-03-19 13:23:34 +00:00
repl [SPARK-13928] Move org.apache.spark.Logging into org.apache.spark.internal.Logging 2016-03-17 19:23:38 +08:00
sbin [SPARK-13848][SPARK-5185] Update to Py4J 0.9.2 in order to fix classloading issue 2016-03-14 12:22:02 -07:00
sql [SPARK-13897][SQL] RelationalGroupedDataset and KeyValueGroupedDataset 2016-03-19 11:23:14 -07:00
streaming [SPARK-13921] Store serialized blocks as multiple chunks in MemoryStore 2016-03-17 20:00:56 -07:00
tools [SPARK-13920][BUILD] MIMA checks should apply to @Experimental and @DeveloperAPI APIs 2016-03-15 23:25:31 -07:00
yarn [SPARK-13885][YARN] Fix attempt id regression for Spark running on Yarn 2016-03-18 12:39:49 -07:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [SPARK-13596][BUILD] Move misc top-level build files into appropriate subdirs 2016-03-07 14:48:02 -08:00
CONTRIBUTING.md [SPARK-6889] [DOCS] CONTRIBUTING.md updates to accompany contribution doc updates 2015-04-21 22:34:31 -07:00
LICENSE [SPARK-13848][SPARK-5185] Update to Py4J 0.9.2 in order to fix classloading issue 2016-03-14 12:22:02 -07:00
NOTICE [SPARK-8725][PROJECT-INFRA] Test modules in topologically-sorted order in dev/run-tests 2016-01-26 14:20:11 -08:00
pom.xml [SPARK-13576][BUILD] Don't create assembly for examples. 2016-03-15 09:44:51 -07:00
README.md Add links howto to setup IDEs for developing spark 2015-12-04 14:43:16 +00:00
scalastyle-config.xml [SPARK-3854][BUILD] Scala style: require spaces before {. 2016-03-10 15:57:22 -08:00

Apache Spark

Spark is a fast and general cluster computing system for Big Data. It provides high-level APIs in Scala, Java, Python, and R, and an optimized engine that supports general computation graphs for data analysis. It also supports a rich set of higher-level tools including Spark SQL for SQL and DataFrames, MLlib for machine learning, GraphX for graph processing, and Spark Streaming for stream processing.

http://spark.apache.org/

Online Documentation

You can find the latest Spark documentation, including a programming guide, on the project web page and project wiki. This README file only contains basic setup instructions.

Building Spark

Spark is built using Apache Maven. To build Spark and its example programs, run:

build/mvn -DskipTests clean package

(You do not need to do this if you downloaded a pre-built package.) More detailed documentation is available from the project site, at "Building Spark". For developing Spark using an IDE, see Eclipse and IntelliJ.

Interactive Scala Shell

The easiest way to start using Spark is through the Scala shell:

./bin/spark-shell

Try the following command, which should return 1000:

scala> sc.parallelize(1 to 1000).count()

Interactive Python Shell

Alternatively, if you prefer Python, you can use the Python shell:

./bin/pyspark

And run the following command, which should also return 1000:

>>> sc.parallelize(range(1000)).count()

Example Programs

Spark also comes with several sample programs in the examples directory. To run one of them, use ./bin/run-example <class> [params]. For example:

./bin/run-example SparkPi

will run the Pi example locally.

You can set the MASTER environment variable when running examples to submit examples to a cluster. This can be a mesos:// or spark:// URL, "yarn" to run on YARN, and "local" to run locally with one thread, or "local[N]" to run locally with N threads. You can also use an abbreviated class name if the class is in the examples package. For instance:

MASTER=spark://host:7077 ./bin/run-example SparkPi

Many of the example programs print usage help if no params are given.

Running Tests

Testing first requires building Spark. Once Spark is built, tests can be run using:

./dev/run-tests

Please see the guidance on how to run tests for a module, or individual tests.

A Note About Hadoop Versions

Spark uses the Hadoop core library to talk to HDFS and other Hadoop-supported storage systems. Because the protocols have changed in different versions of Hadoop, you must build Spark against the same version that your cluster runs.

Please refer to the build documentation at "Specifying the Hadoop Version" for detailed guidance on building for a particular distribution of Hadoop, including building for particular Hive and Hive Thriftserver distributions.

Configuration

Please refer to the Configuration Guide in the online documentation for an overview on how to configure Spark.