Apache Spark - A unified analytics engine for large-scale data processing
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Brian Lindblom 0cea9e3cd0
[SPARK-24855][SQL][EXTERNAL] Built-in AVRO support should support specified schema on write
## What changes were proposed in this pull request?

Allows `avroSchema` option to be specified on write, allowing a user to specify a schema in cases where this is required.  A trivial use case is reading in an avro dataset, making some small adjustment to a column or columns and writing out using the same schema.  Implicit schema creation from SQL Struct results in a schema that while for the most part, is functionally similar, is not necessarily compatible.

Allows `fixed` Field type to be utilized for records of specified `avroSchema`

## How was this patch tested?

Unit tests in AvroSuite are extended to test this with enum and fixed types.

Please review http://spark.apache.org/contributing.html before opening a pull request.

Closes #21847 from lindblombr/specify_schema_on_write.

Lead-authored-by: Brian Lindblom <blindblom@apple.com>
Co-authored-by: DB Tsai <d_tsai@apple.com>
Signed-off-by: DB Tsai <d_tsai@apple.com>
2018-08-10 03:35:29 +00:00
.github [SPARK-18073][DOCS][WIP] Migrate wiki to spark.apache.org web site 2016-11-23 11:25:47 +00:00
assembly [SPARK-25015][BUILD] Update Hadoop 2.7 to 2.7.7 2018-08-04 14:59:13 -05:00
bin [SPARK-24551][K8S] Add integration tests for secrets 2018-07-20 07:55:58 -05:00
build [SPARK-24533] Typesafe rebranded to lightbend. Changing the build downloads path 2018-06-27 14:37:24 -07:00
common [SPARK-25001][BUILD] Fix miscellaneous build warnings 2018-08-04 11:52:49 -05:00
conf [SPARK-22466][SPARK SUBMIT] export SPARK_CONF_DIR while conf is default 2017-11-09 14:33:08 +09:00
core [MINOR][DOC] Fix typo 2018-08-09 20:10:17 +08:00
data [SPARK-23205][ML] Update ImageSchema.readImages to correctly set alpha values for four-channel images 2018-01-25 18:15:29 -06:00
dev [SPARK-24886][INFRA] Fix the testing script to increase timeout for Jenkins build (from 300m to 340m) 2018-08-10 09:12:17 +08:00
docs [SPARK-24626][SQL] Improve location size calculation in Analyze Table command 2018-08-09 08:29:24 -07:00
examples [SPARK-23633][SQL] Update Pandas UDFs section in sql-programming-guide 2018-07-31 10:10:38 +08:00
external [SPARK-24855][SQL][EXTERNAL] Built-in AVRO support should support specified schema on write 2018-08-10 03:35:29 +00:00
graphx [SPARK-25029][TESTS] Scala 2.12 issues: TaskNotSerializable and Janino "Two non-abstract methods ..." errors 2018-08-07 17:30:37 -05:00
hadoop-cloud [SPARK-23807][BUILD] Add Hadoop 3.1 profile with relevant POM fix ups 2018-04-24 09:57:09 -07:00
launcher [SPARK-25001][BUILD] Fix miscellaneous build warnings 2018-08-04 11:52:49 -05:00
licenses [SPARK-24654][BUILD] Update, fix LICENSE and NOTICE, and specialize for source vs binary 2018-06-30 19:27:16 -05:00
licenses-binary [SPARK-24654][BUILD] Update, fix LICENSE and NOTICE, and specialize for source vs binary 2018-06-30 19:27:16 -05:00
mllib [SPARK-25047][ML] Can't assign SerializedLambda to scala.Function1 in deserialization of BucketedRandomProjectionLSHModel 2018-08-09 08:07:46 -05:00
mllib-local [SPARK-23085][ML] API parity for mllib.linalg.Vectors.sparse 2018-01-19 09:28:35 -06:00
project [SPARK-25041][BUILD] upgrade genJavaDoc-plugin from 0.10 to 0.11 2018-08-07 11:58:44 -05:00
python [MINOR][DOC] Fix typo 2018-08-09 20:10:17 +08:00
R [SPARK-24609][ML][DOC] PySpark/SparkR doc doesn't explain RandomForestClassifier.featureSubsetStrategy well 2018-07-31 13:37:13 -05:00
repl [SPARK-25029][TESTS] Scala 2.12 issues: TaskNotSerializable and Janino "Two non-abstract methods ..." errors 2018-08-07 17:30:37 -05:00
resource-managers [SPARK-24960][K8S] explicitly expose ports on driver container 2018-08-01 13:57:33 -07:00
sbin [PYSPARK] Update py4j to version 0.10.7. 2018-05-09 10:47:35 -07:00
sql [SPARK-24251][SQL] Add analysis tests for AppendData. 2018-08-10 11:10:23 +08:00
streaming [SPARK-24005][CORE] Remove usage of Scala’s parallel collection 2018-08-07 17:14:30 +08:00
tools [SPARK-23028] Bump master branch version to 2.4.0-SNAPSHOT 2018-01-13 00:37:59 +08:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [SPARK-23572][DOCS] Bring "security.md" up to date. 2018-03-26 12:45:45 -07:00
.travis.yml [SPARK-18278][SCHEDULER] Spark on Kubernetes - Basic Scheduler Backend 2017-11-28 23:02:09 -08:00
appveyor.yml [MINOR][BUILD] Remove -Phive-thriftserver profile within appveyor.yml 2018-07-30 10:01:18 +08:00
CONTRIBUTING.md [SPARK-18073][DOCS][WIP] Migrate wiki to spark.apache.org web site 2016-11-23 11:25:47 +00:00
LICENSE [SPARK-24654][BUILD] Update, fix LICENSE and NOTICE, and specialize for source vs binary 2018-06-30 19:27:16 -05:00
LICENSE-binary [SPARK-24654][BUILD] Update, fix LICENSE and NOTICE, and specialize for source vs binary 2018-06-30 19:27:16 -05:00
NOTICE [SPARK-24654][BUILD] Update, fix LICENSE and NOTICE, and specialize for source vs binary 2018-06-30 19:27:16 -05:00
NOTICE-binary [SPARK-24654][BUILD] Update, fix LICENSE and NOTICE, and specialize for source vs binary 2018-06-30 19:27:16 -05:00
pom.xml [MINOR][BUILD] Update Jetty to 9.3.24.v20180605 2018-08-09 13:04:03 -05:00
README.md [SPARK-23010][K8S] Initial checkin of k8s integration tests. 2018-06-08 15:15:24 -07:00
scalastyle-config.xml [SPARK-24919][BUILD] New linter rule for sparkContext.hadoopConfiguration 2018-07-26 16:50:59 -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. 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 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.

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" 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.