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navis.ryu authored
This patch fixes a managed memory leak in GeneratedAggregate.  The leak occurs when the unsafe aggregation path is used to perform grouped aggregation on an empty input; in this case, GeneratedAggregate allocates an UnsafeFixedWidthAggregationMap that is never cleaned up because `next()` is never called on the aggregate result iterator.

This patch fixes this by short-circuiting on empty inputs.

This patch is an updated version of #6810.

Closes #6810.

Author: navis.ryu <navis@apache.org>
Author: Josh Rosen <joshrosen@databricks.com>

Closes #7560 from JoshRosen/SPARK-8357 and squashes the following commits:

3486ce4 [Josh Rosen] Some minor cleanup
c649310 [Josh Rosen] Revert SparkPlan change:
3c7db0f [Josh Rosen] Merge remote-tracking branch 'origin/master' into SPARK-8357
adc8239 [Josh Rosen] Back out Projection changes.
c5419b3 [navis.ryu] addressed comments
143e1ef [navis.ryu] fixed format & added test for CCE case
735972f [navis.ryu] used new conf apis
1a02a55 [navis.ryu] Rolled-back test-conf cleanup & fixed possible CCE & added more tests
51178e8 [navis.ryu] addressed comments
4d326b9 [navis.ryu] fixed test fails
15c5afc [navis.ryu] added a test as suggested by JoshRosen
d396589 [navis.ryu] added comments
1b07556 [navis.ryu] [SPARK-8357] [SQL] Memory leakage on unsafe aggregation path with empty input
9ba7c64d
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.