Apache Spark - A unified analytics engine for large-scale data processing
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Herman van Hovell df10658831 [SPARK-16749][SQL] Simplify processing logic in LEAD/LAG processing.
## What changes were proposed in this pull request?
The logic for LEAD/LAG processing is more complex that it needs to be. This PR fixes that.

## How was this patch tested?
Existing tests.

Author: Herman van Hovell <hvanhovell@databricks.com>

Closes #14376 from hvanhovell/SPARK-16749.
2016-08-08 16:34:57 -07:00
.github [MINOR][MAINTENANCE] Fix typo for the pull request template. 2016-02-24 00:45:31 -08:00
assembly [SPARK-16535][BUILD] In pom.xml, remove groupId which is redundant definition and inherited from the parent 2016-07-19 11:59:46 +01:00
bin [SPARK-16586][CORE] Handle JVM errors printed to stdout. 2016-08-08 10:34:54 -07:00
build [SPARK-14279][BUILD] Pick the spark version from pom 2016-06-06 09:42:50 -07:00
common [HOTFIX] Remove unnecessary imports from #12944 that broke build 2016-08-04 15:26:27 -07:00
conf [SPARK-13238][CORE] Add ganglia dmax parameter 2016-08-05 13:07:52 -07:00
core [SPARK-16779][TRIVIAL] Avoid using postfix operators where they do not add much and remove whitelisting 2016-08-08 15:54:03 -07:00
data [SPARK-16421][EXAMPLES][ML] Improve ML Example Outputs 2016-08-05 20:57:46 +01:00
dev [SPARK-16770][BUILD] Fix JLine dependency management and version (Sca… 2016-08-03 17:07:10 -07:00
docs Update docs to include SASL support for RPC 2016-08-08 16:07:51 -07:00
examples [SPARK-16945] Fix Java Lint errors 2016-08-08 09:24:37 +01:00
external [SPARK-16779][TRIVIAL] Avoid using postfix operators where they do not add much and remove whitelisting 2016-08-08 15:54:03 -07:00
graphx [SPARK-16779][TRIVIAL] Avoid using postfix operators where they do not add much and remove whitelisting 2016-08-08 15:54:03 -07:00
launcher [SPARK-14702] Make environment of SparkLauncher launched process more configurable 2016-07-19 17:08:38 -07:00
licenses [MINOR][BUILD] Add modernizr MIT license; specify "2014 and onwards" in license copyright 2016-06-04 21:41:27 +01:00
mllib [SPARK-16779][TRIVIAL] Avoid using postfix operators where they do not add much and remove whitelisting 2016-08-08 15:54:03 -07:00
mllib-local [SPARK-16535][BUILD] In pom.xml, remove groupId which is redundant definition and inherited from the parent 2016-07-19 11:59:46 +01:00
project [SPARK-16853][SQL] fixes encoder error in DataSet typed select 2016-08-04 19:45:47 +08:00
python [SPARK-16409][SQL] regexp_extract with optional groups causes NPE 2016-08-07 12:20:07 +01:00
R [SPARKR][DOCS] fix broken url in doc 2016-07-25 11:25:41 -07:00
repl [SPARK-16779][TRIVIAL] Avoid using postfix operators where they do not add much and remove whitelisting 2016-08-08 15:54:03 -07:00
sbin [SPARK-15806][DOCUMENTATION] update doc for SPARK_MASTER_IP 2016-06-12 14:25:48 +01:00
sql [SPARK-16749][SQL] Simplify processing logic in LEAD/LAG processing. 2016-08-08 16:34:57 -07:00
streaming [SPARK-16779][TRIVIAL] Avoid using postfix operators where they do not add much and remove whitelisting 2016-08-08 15:54:03 -07:00
tools [SPARK-16535][BUILD] In pom.xml, remove groupId which is redundant definition and inherited from the parent 2016-07-19 11:59:46 +01:00
yarn [SPARK-16779][TRIVIAL] Avoid using postfix operators where they do not add much and remove whitelisting 2016-08-08 15:54:03 -07:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [GIT] add pydev & Rstudio project file to gitignore list 2016-07-22 12:40:41 +01:00
.travis.yml [SPARK-15207][BUILD] Use Travis CI for Java Linter and JDK7/8 compilation test 2016-05-10 21:04:22 +01:00
CONTRIBUTING.md [SPARK-6889] [DOCS] CONTRIBUTING.md updates to accompany contribution doc updates 2015-04-21 22:34:31 -07:00
LICENSE [MINOR][BUILD] Add modernizr MIT license; specify "2014 and onwards" in license copyright 2016-06-04 21:41:27 +01:00
NOTICE [MINOR][BUILD] Add modernizr MIT license; specify "2014 and onwards" in license copyright 2016-06-04 21:41:27 +01:00
pom.xml [SPARK-16770][BUILD] Fix JLine dependency management and version (Sca… 2016-08-03 17:07:10 -07:00
README.md [SPARK-15821][DOCS] Include parallel build info 2016-06-14 13:59:01 +01:00
scalastyle-config.xml [SPARK-16877][BUILD] Add rules for preventing to use Java annotations (Deprecated and Override) 2016-08-04 21:43:05 +01:00

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.)

You can build Spark using more than one thread by using the -T option with Maven, see "Parallel builds in Maven 3". 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.