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Davies Liu authored
This PR introduce unsafe version (using UnsafeRow) of HashJoin, HashOuterJoin and HashSemiJoin, including the broadcast one and shuffle one (except FullOuterJoin, which is better to be implemented using SortMergeJoin).

It use HashMap to store UnsafeRow right now, will change to use BytesToBytesMap for better performance (in another PR).

Author: Davies Liu <davies@databricks.com>

Closes #7480 from davies/unsafe_join and squashes the following commits:

6294b1e [Davies Liu] fix projection
10583f1 [Davies Liu] Merge branch 'master' of github.com:apache/spark into unsafe_join
dede020 [Davies Liu] fix test
84c9807 [Davies Liu] address comments
a05b4f6 [Davies Liu] support UnsafeRow in LeftSemiJoinBNL and BroadcastNestedLoopJoin
611d2ed [Davies Liu] Merge branch 'master' of github.com:apache/spark into unsafe_join
9481ae8 [Davies Liu] return UnsafeRow after join()
ca2b40f [Davies Liu] revert unrelated change
68f5cd9 [Davies Liu] Merge branch 'master' of github.com:apache/spark into unsafe_join
0f4380d [Davies Liu] ada a comment
69e38f5 [Davies Liu] Merge branch 'master' of github.com:apache/spark into unsafe_join
1a40f02 [Davies Liu] refactor
ab1690f [Davies Liu] address comments
60371f2 [Davies Liu] use UnsafeRow in SemiJoin
a6c0b7d [Davies Liu] Merge branch 'master' of github.com:apache/spark into unsafe_join
184b852 [Davies Liu] fix style
6acbb11 [Davies Liu] fix tests
95d0762 [Davies Liu] remove println
bea4a50 [Davies Liu] Unsafe HashJoin
e0b7ba59
History

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.