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Davies Liu authored
In order to reduce the overhead of codegen, this PR switch to use Janino to compile SQL expressions into bytecode.

After this, the time used to compile a SQL expression is decreased from 100ms to 5ms, which is necessary to turn on codegen for general workload, also tests.

cc rxin

Author: Davies Liu <davies@databricks.com>

Closes #6479 from davies/janino and squashes the following commits:

cc689f5 [Davies Liu] remove globalLock
262d848 [Davies Liu] Merge branch 'master' of github.com:apache/spark into janino
eec3a33 [Davies Liu] address comments from Josh
f37c8c3 [Davies Liu] fix DecimalType and cast to String
202298b [Davies Liu] Merge branch 'master' of github.com:apache/spark into janino
a21e968 [Davies Liu] fix style
0ed3dc6 [Davies Liu] Merge branch 'master' of github.com:apache/spark into janino
551a851 [Davies Liu] fix tests
c3bdffa [Davies Liu] remove print
6089ce5 [Davies Liu] change logging level
7e46ac3 [Davies Liu] fix style
d8f0f6c [Davies Liu] Merge branch 'master' of github.com:apache/spark into janino
da4926a [Davies Liu] fix tests
03660f3 [Davies Liu] WIP: use Janino to compile Java source
f2629cd [Davies Liu] Merge branch 'master' of github.com:apache/spark into janino
f7d66cf [Davies Liu] use template based string for codegen
c8709dcf
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Apache Spark

Spark is a fast and general cluster computing system for Big Data. It provides high-level APIs in Scala, Java, and Python, 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".

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-cluster" or "yarn-client" 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. See also "Third Party Hadoop Distributions" for guidance on building a Spark application that works with a particular distribution.

Configuration

Please refer to the Configuration guide in the online documentation for an overview on how to configure Spark.