Apache Spark - A unified analytics engine for large-scale data processing
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HyukjinKwon b83b7927b3 [SPARK-27234][SS][PYTHON] Use InheritableThreadLocal for current epoch in EpochTracker (to support Python UDFs)
## What changes were proposed in this pull request?

This PR proposes to use `InheritableThreadLocal` instead of `ThreadLocal` for current epoch in `EpochTracker`. Python UDF needs threads to write out to and read it from Python processes and when there are new threads, previously set epoch is lost.

After this PR, Python UDFs can be used at Structured Streaming with the continuous mode.

## How was this patch tested?

The test cases were written on the top of https://github.com/apache/spark/pull/24945.
Unit tests were added.

Manual tests.

Closes #24946 from HyukjinKwon/SPARK-27234.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-07-24 09:59:37 +09:00
.github [MINOR][DOCS] Tighten up some key links to the project and download pages to use HTTPS 2019-05-21 10:56:42 -07:00
assembly [SPARK-27300][GRAPH] Add Spark Graph modules and dependencies 2019-06-09 00:26:26 -07:00
bin [SPARK-28302][CORE] Make sure to generate unique output file for SparkLauncher on Windows 2019-07-09 15:49:31 +09:00
build [SPARK-27979][BUILD][test-maven] Remove deprecated --force option in build/mvn and run-tests.py 2019-06-10 18:40:46 -07:00
common [SPARK-28107][SQL] Support 'DAY TO (HOUR|MINUTE|SECOND)', 'HOUR TO (MINUTE|SECOND)' and 'MINUTE TO SECOND' 2019-07-10 18:01:42 -07:00
conf [SPARK-27796][MESOS] Remove obsolete spark-mesos Dockerfile example 2019-05-21 10:53:55 -07:00
core [SPARK-28455][CORE] Avoid overflow when calculating executor timeout time 2019-07-22 14:31:58 -07:00
data [SPARK-22666][ML][SQL] Spark datasource for image format 2018-09-05 11:59:00 -07:00
dev [SPARK-28381][PYSPARK] Upgraded version of Pyrolite to 4.30 2019-07-15 12:29:58 +09:00
docs [SPARK-28473][DOC] Stylistic consistency of build command in README 2019-07-23 16:29:46 -07:00
examples [SPARK-28226][PYTHON] Document Pandas UDF mapInPandas 2019-07-07 09:07:52 +09:00
external [SPARK-28469][SQL] Change CalendarIntervalType's readable string representation from calendarinterval to interval 2019-07-22 20:53:59 -07:00
graph [SPARK-27300][GRAPH] Add Spark Graph modules and dependencies 2019-06-09 00:26:26 -07:00
graphx [SPARK-27682][CORE][GRAPHX][MLLIB] Replace use of collections and methods that will be removed in Scala 2.13 with work-alikes 2019-05-15 09:29:12 -05:00
hadoop-cloud [SPARK-28187][BUILD] Add support for hadoop-cloud to the PR builder. 2019-06-27 15:59:05 -07:00
launcher [SPARK-23472][CORE] Add defaultJavaOptions for driver and executor. 2019-07-11 09:37:26 -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-27358][UI] Update jquery to 1.12.x to pick up security fixes 2019-04-05 12:54:01 -05:00
mllib [SPARK-28440][MLLIB][TEST] Use TestingUtils to compare floating point values 2019-07-18 23:48:12 -07:00
mllib-local [SPARK-19591][ML][MLLIB] Add sample weights to decision trees 2019-01-24 18:20:28 -07:00
project [SPARK-28199][SS] Move Trigger implementations to Triggers.scala and avoid exposing these to the end users 2019-07-14 14:46:01 -05:00
python [SPARK-28243][PYSPARK][ML] Remove setFeatureSubsetStrategy and setSubsamplingRate from Python TreeEnsembleParams 2019-07-20 10:44:33 -05:00
R [SPARK-28473][DOC] Stylistic consistency of build command in README 2019-07-23 16:29:46 -07:00
repl [SPARK-20547][REPL] Throw RemoteClassLoadedError for transient errors in ExecutorClassLoader 2019-05-28 12:56:14 -07:00
resource-managers [SPARK-28473][DOC] Stylistic consistency of build command in README 2019-07-23 16:29:46 -07:00
sbin [SPARK-28164] Fix usage description of start-slave.sh 2019-06-26 12:42:33 -05:00
sql [SPARK-27234][SS][PYTHON] Use InheritableThreadLocal for current epoch in EpochTracker (to support Python UDFs) 2019-07-24 09:59:37 +09:00
streaming [SPARK-28101][DSTREAM][TEST] Fix Flaky Test: InputStreamsSuite.Modified files are correctly detected in JDK9+ 2019-06-19 07:55:00 -07:00
tools [SPARK-25956] Make Scala 2.12 as default Scala version in Spark 3.0 2018-11-14 16:22:23 -08:00
.gitattributes [SPARK-3870] EOL character enforcement 2014-10-31 12:39:52 -07:00
.gitignore [MINOR][DOC] Documentation on JVM options for SBT 2019-01-22 18:27:24 -06:00
appveyor.yml [SPARK-28309][R][INFRA] Fix AppVeyor to run SparkR tests by avoiding to use devtools for testthat 2019-07-09 12:06:46 +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 [SPARK-27557][DOC] Add copy button to Python API docs for easier copying of code-blocks 2019-05-01 11:26:18 -05:00
LICENSE-binary [SPARK-27300][GRAPH] Add Spark Graph modules and dependencies 2019-06-09 00:26:26 -07:00
NOTICE [SPARK-23654][BUILD] remove jets3t as a dependency of spark 2018-08-16 12:34:23 -07:00
NOTICE-binary [SPARK-27862][BUILD] Move to json4s 3.6.6 2019-05-30 19:42:56 -05:00
pom.xml [SPARK-28370][BUILD][TEST] Upgrade Mockito to 2.28.2 2019-07-13 13:00:07 -07:00
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.