Apache Spark - A unified analytics engine for large-scale data processing
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gatorsmile 8f90c15187 [SPARK-12616][SQL] Making Logical Operator Union Support Arbitrary Number of Children
The existing `Union` logical operator only supports two children. Thus, adding a new logical operator `Unions` which can have arbitrary number of children to replace the existing one.

`Union` logical plan is a binary node. However, a typical use case for union is to union a very large number of input sources (DataFrames, RDDs, or files). It is not uncommon to union hundreds of thousands of files. In this case, our optimizer can become very slow due to the large number of logical unions. We should change the Union logical plan to support an arbitrary number of children, and add a single rule in the optimizer to collapse all adjacent `Unions` into a single `Unions`. Note that this problem doesn't exist in physical plan, because the physical `Unions` already supports arbitrary number of children.

Author: gatorsmile <gatorsmile@gmail.com>
Author: xiaoli <lixiao1983@gmail.com>
Author: Xiao Li <xiaoli@Xiaos-MacBook-Pro.local>

Closes #10577 from gatorsmile/unionAllMultiChildren.
2016-01-20 14:59:30 -08:00
assembly [SPARK-11808] Remove Bagel. 2015-12-19 22:40:35 -08:00
bin [SPARK-12652][PYSPARK] Upgrade Py4J to 0.9.1 2016-01-12 14:27:05 -08:00
build [SPARK-12475][BUILD] Upgrade Zinc from 0.3.5.3 to 0.3.9 2015-12-22 10:23:24 -08:00
conf [SPARK-11929][CORE] Make the repl log4j configuration override the root logger. 2015-11-24 15:08:02 -06:00
core [SPARK-12847][CORE][STREAMING] Remove StreamingListenerBus and post all Streaming events to the same thread as Spark events 2016-01-20 11:57:53 -08:00
data [SPARK-9057][STREAMING] Twitter example joining to static RDD of word sentiment values 2015-12-18 15:06:54 +00:00
dev [SPARK-7799][SPARK-12786][STREAMING] Add "streaming-akka" project 2016-01-20 13:55:41 -08:00
docker [SPARK-11491] Update build to use Scala 2.10.5 2015-11-04 16:58:38 -08:00
docker-integration-tests [SPARK-3873][TESTS] Import ordering fixes. 2016-01-05 19:07:39 -08:00
docs [SPARK-7799][SPARK-12786][STREAMING] Add "streaming-akka" project 2016-01-20 13:55:41 -08:00
examples [SPARK-7799][SPARK-12786][STREAMING] Add "streaming-akka" project 2016-01-20 13:55:41 -08:00
external [SPARK-7799][SPARK-12786][STREAMING] Add "streaming-akka" project 2016-01-20 13:55:41 -08:00
extras [SPARK-12692][BUILD][HOT-FIX] Fix the scala style of KinesisBackedBlockRDDSuite.scala. 2016-01-13 10:01:15 -08:00
graphx [SPARK-12655][GRAPHX] GraphX does not unpersist RDDs 2016-01-15 12:04:05 +00:00
launcher [SPARK-12707][SPARK SUBMIT] Remove submit python/R scripts through py… 2016-01-13 23:50:08 -08:00
licenses [SPARK-10833] [BUILD] Inline, organize BSD/MIT licenses in LICENSE 2015-09-28 22:56:43 -04:00
mllib [SPARK-10263][ML] Add @Since annotation to ml.param and ml.* 2016-01-20 11:44:04 -08:00
network [SPARK-12830] Java style: disallow trailing whitespaces. 2016-01-14 23:33:45 -08:00
project [SPARK-7799][SPARK-12786][STREAMING] Add "streaming-akka" project 2016-01-20 13:55:41 -08:00
python [SPARK-11295][PYSPARK] Add packages to JUnit output for Python tests 2016-01-20 11:11:10 -08:00
R [SPARK-12232][SPARKR] New R API for read.table to avoid name conflict 2016-01-19 18:31:03 -08:00
repl [SPARK-12761][CORE] Remove duplicated code 2016-01-13 11:53:59 -08:00
sbin [SPARK-12652][PYSPARK] Upgrade Py4J to 0.9.1 2016-01-12 14:27:05 -08:00
sbt Adde LICENSE Header to build/mvn, build/sbt and sbt/sbt 2014-12-29 10:48:53 -08:00
sql [SPARK-12616][SQL] Making Logical Operator Union Support Arbitrary Number of Children 2016-01-20 14:59:30 -08:00
streaming [SPARK-7799][SPARK-12786][STREAMING] Add "streaming-akka" project 2016-01-20 13:55:41 -08:00
tags Bump master version to 2.0.0-SNAPSHOT. 2015-12-19 15:13:05 -08:00
tools [SPARK-4819] Remove Guava's "Optional" from public API 2016-01-08 13:02:30 -08:00
unsafe [SQL] [MINOR] speed up hashcode for UTF8String 2016-01-17 11:02:37 -08:00
yarn [SPARK-12652][PYSPARK] Upgrade Py4J to 0.9.1 2016-01-12 14:27:05 -08:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [SPARK-12735] Consolidate & move spark-ec2 to AMPLab managed repository. 2016-01-09 20:28:20 -08:00
.rat-excludes [SPARK-12833][SQL] Initial import of spark-csv 2016-01-15 11:46:46 -08:00
checkstyle-suppressions.xml [SPARK-6990][BUILD] Add Java linting script; fix minor warnings 2015-12-04 12:03:45 -08:00
checkstyle.xml [SPARK-12830] Java style: disallow trailing whitespaces. 2016-01-14 23:33:45 -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-12652][PYSPARK] Upgrade Py4J to 0.9.1 2016-01-12 14:27:05 -08:00
make-distribution.sh [SPARK-12735] Consolidate & move spark-ec2 to AMPLab managed repository. 2016-01-09 20:28:20 -08:00
NOTICE [SPARK-12833][SQL] Initial import of spark-csv 2016-01-15 11:46:46 -08:00
pom.xml [SPARK-7799][SPARK-12786][STREAMING] Add "streaming-akka" project 2016-01-20 13:55:41 -08:00
pylintrc [SPARK-9116] [SQL] [PYSPARK] support Python only UDT in __main__ 2015-07-29 22:30:49 -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-12692][BUILD] Enforce style checking about white space before comma 2016-01-13 00:51:24 -08:00
tox.ini [SPARK-7427] [PYSPARK] Make sharedParams match in Scala, Python 2015-05-10 19:18:32 -07:00

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.