Apache Spark - A unified analytics engine for large-scale data processing
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Dilip Biswal c1c64851ed [SPARK-28793][DOC][SQL] Document CREATE FUNCTION in SQL Reference
### What changes were proposed in this pull request?
Document CREATE FUNCTION statement in SQL Reference Guide.

### Why are the changes needed?
Currently Spark lacks documentation on the supported SQL constructs causing
confusion among users who sometimes have to look at the code to understand the
usage. This is aimed at addressing this issue.

### Does this PR introduce any user-facing change?
Yes.

**Before:**
There was no documentation for this.

**After.**
<img width="1260" alt="Screen Shot 2019-09-22 at 3 01 52 PM" src="https://user-images.githubusercontent.com/14225158/65395036-5bdc6680-dd4a-11e9-9873-0a1da88706a8.png">
<img width="1260" alt="Screen Shot 2019-09-22 at 3 02 11 PM" src="https://user-images.githubusercontent.com/14225158/65395037-5bdc6680-dd4a-11e9-964f-c02d23803b68.png">
<img width="1260" alt="Screen Shot 2019-09-22 at 3 02 39 PM" src="https://user-images.githubusercontent.com/14225158/65395038-5bdc6680-dd4a-11e9-831b-6ba1d041893d.png">
<img width="1260" alt="Screen Shot 2019-09-22 at 3 04 04 PM" src="https://user-images.githubusercontent.com/14225158/65395040-5bdc6680-dd4a-11e9-8226-250f77dfeaf3.png">

### How was this patch tested?
Tested using jykyll build --serve

Closes #25894 from dilipbiswal/sql-ref-create-function.

Authored-by: Dilip Biswal <dkbiswal@gmail.com>
Signed-off-by: Sean Owen <sean.owen@databricks.com>
2019-10-22 08:56:44 -05:00
.github [SPARK-29199][INFRA] Add linters and license/dependency checkers to GitHub Action 2019-09-21 08:13:00 -07:00
assembly [SPARK-27300][GRAPH] Add Spark Graph modules and dependencies 2019-06-09 00:26:26 -07:00
bin [SPARK-28525][DEPLOY] Allow Launcher to be applied Java options 2019-07-30 12:45:32 -07:00
build [SPARK-29159][BUILD] Increase ReservedCodeCacheSize to 1G 2019-09-19 00:24:15 -07:00
common [SPARK-9853][CORE] Optimize shuffle fetch of continuous partition IDs 2019-10-17 14:47:56 +08:00
conf [SPARK-29032][CORE] Add PrometheusServlet to monitor Master/Worker/Driver 2019-09-13 21:31:21 +00:00
core [SPARK-29434][CORE] Improve the MapStatuses Serialization Performance 2019-10-20 13:56:23 -07:00
data [SPARK-22666][ML][SQL] Spark datasource for image format 2018-09-05 11:59:00 -07:00
dev [SPARK-27812][K8S] Bump K8S client version to 4.6.1 2019-10-17 12:23:24 -07:00
docs [SPARK-28793][DOC][SQL] Document CREATE FUNCTION in SQL Reference 2019-10-22 08:56:44 -05:00
examples [MINOR][DOCS] Fix some typos 2019-10-17 07:22:01 -07:00
external [SPARK-29392][CORE][SQL][STREAMING] Remove symbol literal syntax 'foo, deprecated in Scala 2.13, in favor of Symbol("foo") 2019-10-08 20:15:37 -07:00
graph [SPARK-27300][GRAPH] Add Spark Graph modules and dependencies 2019-06-09 00:26:26 -07:00
graphx [SPARK-29401][FOLLOWUP] Additional cases where a .parallelize call with Array is ambiguous in 2.13 2019-10-09 10:27:05 -07:00
hadoop-cloud [SPARK-28903][STREAMING][PYSPARK][TESTS] Fix AWS JDK version conflict that breaks Pyspark Kinesis tests 2019-08-31 10:29:46 -05:00
launcher [SPARK-29070][CORE] Make SparkLauncher log full spark-submit command line 2019-09-27 11:32:22 -07:00
licenses [SPARK-27557][DOC] Add copy button to Python API docs for easier copying of code-blocks 2019-05-01 11:26:18 -05:00
licenses-binary [SPARK-29308][BUILD] Update deps in dev/deps/spark-deps-hadoop-3.2 for hadoop-3.2 2019-10-13 12:53:12 -05:00
mllib [SPARK-29232][ML] Update the parameter maps of the DecisionTreeRegression/Classification Models 2019-10-22 17:49:44 +08:00
mllib-local [SPARK-29307][BUILD][TESTS] Remove scalatest deprecation warnings 2019-09-30 21:00:11 -07:00
project [SPARK-29470][BUILD] Update plugins to latest versions 2019-10-15 11:55:52 -07:00
python [SPARK-29536][PYTHON] Upgrade cloudpickle to 1.1.1 to support Python 3.8 2019-10-22 16:18:34 +09:00
R [SPARK-29339][R] Support Arrow 0.14 in vectoried dapply and gapply (test it in AppVeyor build) 2019-10-04 08:56:45 +09:00
repl [SPARK-29307][BUILD][TESTS] Remove scalatest deprecation warnings 2019-09-30 21:00:11 -07:00
resource-managers [SPARK-27812][K8S] Bump K8S client version to 4.6.1 2019-10-17 12:23:24 -07:00
sbin [SPARK-28164] Fix usage description of start-slave.sh 2019-06-26 12:42:33 -05:00
sql [SPARK-29517][SQL] TRUNCATE TABLE should look up catalog/table like v2 commands 2019-10-22 19:17:28 +08:00
streaming [SPARK-29411][CORE][ML][SQL][DSTREAM] Replace use of Unit object with () for Scala 2.13 2019-10-09 10:24:13 -07:00
tools [SPARK-29291][CORE][SQL][STREAMING][MLLIB] Change procedure-like declaration to function + Unit for 2.13 2019-09-30 10:03:23 -07:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [SPARK-27371][CORE] Support GPU-aware resources scheduling in Standalone 2019-08-09 07:49:03 -05:00
appveyor.yml [SPARK-29403][INFRA][R] Uses Arrow R 0.14.1 in AppVeyor for now 2019-10-10 09:01:36 +09:00
CONTRIBUTING.md [MINOR][DOCS] Tighten up some key links to the project and download pages to use HTTPS 2019-05-21 10:56:42 -07:00
LICENSE [MINOR][BUILD] Fix an incorrect path in license file 2019-10-08 14:33:03 +09:00
LICENSE-binary [SPARK-29483][BUILD] Bump Jackson to 2.10.0 2019-10-16 15:38:54 -07:00
NOTICE [SPARK-23654][BUILD] remove jets3t as a dependency of spark 2018-08-16 12:34:23 -07:00
NOTICE-binary [SPARK-29308][BUILD] Update deps in dev/deps/spark-deps-hadoop-3.2 for hadoop-3.2 2019-10-13 12:53:12 -05:00
pom.xml [SPARK-29528][BUILD][TEST-MAVEN] Upgrade scala-maven-plugin to 4.2.4 for Scala 2.13.1 2019-10-21 19:05:27 +09:00
README.md [SPARK-28473][DOC] Stylistic consistency of build command in README 2019-07-23 16:29:46 -07:00
scalastyle-config.xml [SPARK-25986][BUILD] Add rules to ban throw Errors in application code 2018-11-14 13:05:18 -08:00

Apache Spark

Spark is a unified analytics engine for large-scale data processing. 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 Structured Streaming for stream processing.

https://spark.apache.org/

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Online Documentation

You can find the latest Spark documentation, including a programming guide, on the project web page. 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 general development tips, including info on developing Spark using an IDE, see "Useful Developer Tools".

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 1,000,000,000:

scala> spark.range(1000 * 1000 * 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 1,000,000,000:

>>> spark.range(1000 * 1000 * 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.

There is also a Kubernetes integration test, see resource-managers/kubernetes/integration-tests/README.md

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 and Enabling YARN" 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.

Contributing

Please review the Contribution to Spark guide for information on how to get started contributing to the project.