Apache Spark - A unified analytics engine for large-scale data processing
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Steve Loughran ff5115c3ac [SPARK-33739][SQL] Jobs committed through the S3A Magic committer don't track bytes
BasicWriteStatsTracker to probe for a custom Xattr if the size of
the generated file is 0 bytes; if found and parseable use that as
the declared length of the output.

The matching Hadoop patch in HADOOP-17414:

* Returns all S3 object headers as XAttr attributes prefixed "header."
* Sets the custom header x-hadoop-s3a-magic-data-length to the length of
  the data in the marker file.

As a result, spark job tracking will correctly report the amount of data uploaded
and yet to materialize.

### Why are the changes needed?

Now that S3 is consistent, it's a lot easier to use the S3A "magic" committer
which redirects a file written to `dest/__magic/job_0011/task_1245/__base/year=2020/output.avro`
to its final destination `dest/year=2020/output.avro` , adding a zero byte marker file at
the end and a json file `dest/__magic/job_0011/task_1245/__base/year=2020/output.avro.pending`
containing all the information for the job committer to complete the upload.

But: the write tracker statictics don't show progress as they measure the length of the
created file, find the marker file and report 0 bytes.
By probing for a specific HTTP header in the marker file and parsing that if
retrieved, the real progress can be reported.

There's a matching change in Hadoop [https://github.com/apache/hadoop/pull/2530](https://github.com/apache/hadoop/pull/2530)
which adds getXAttr API support to the S3A connector and returns the headers; the magic
committer adds the relevant attributes.

If the FS being probed doesn't support the XAttr API, the header is missing
or the value not a positive long then the size of 0 is returned.

### Does this PR introduce _any_ user-facing change?

No

### How was this patch tested?

New tests in BasicWriteTaskStatsTrackerSuite which use a filter FS to
implement getXAttr on top of LocalFS; this is used to explore the set of
options:
* no XAttr API implementation (existing tests; what callers would see with
  most filesystems)
* no attribute found (HDFS, ABFS without the attribute)
* invalid data of different forms

All of these return Some(0) as file length.

The Hadoop PR verifies XAttr implementation in S3A and that
the commit protocol attaches the header to the files.

External downstream testing has done the full hadoop+spark end
to end operation, with manual review of logs to verify that the
data was successfully collected from the attribute.

Closes #30714 from steveloughran/cdpd/SPARK-33739-magic-commit-tracking-master.

Authored-by: Steve Loughran <stevel@cloudera.com>
Signed-off-by: Thomas Graves <tgraves@apache.org>
2021-02-18 08:43:18 -06:00
.github [SPARK-34433][DOCS] Lock Jekyll version by Gemfile and Bundler 2021-02-18 12:17:57 +09:00
assembly [SPARK-33662][BUILD] Setting version to 3.2.0-SNAPSHOT 2020-12-04 14:10:42 -08:00
bin [SPARK-32866][K8S] Fix docker cross-build 2021-01-28 11:57:42 -08:00
binder [SPARK-32204][SPARK-32182][DOCS] Add a quickstart page with Binder integration in PySpark documentation 2020-08-26 12:23:24 +09:00
build [SPARK-34341][BUILD] Skip zinc related operations on aarch64 2021-02-04 10:41:15 +09:00
common [SPARK-34192][SQL] Move char padding to write side and remove length check on read side too 2021-01-26 02:08:35 +08:00
conf [SPARK-32004][ALL] Drop references to slave 2020-07-13 14:05:33 -07:00
core [SPARK-34449][BUILD] Upgrade Jetty to fix CVE-2020-27218 2021-02-18 18:02:34 +09:00
data [SPARK-22666][ML][SQL] Spark datasource for image format 2018-09-05 11:59:00 -07:00
dev [SPARK-34433][DOCS] Lock Jekyll version by Gemfile and Bundler 2021-02-18 12:17:57 +09:00
docs [SPARK-33739][SQL] Jobs committed through the S3A Magic committer don't track bytes 2021-02-18 08:43:18 -06:00
examples [SPARK-31816][SQL][DOCS] Added high level description about JDBC connection providers for users/developers 2021-02-10 12:28:28 +09:00
external [SPARK-34451][SQL] Add alternatives for datetime rebasing SQL configs and deprecate legacy configs 2021-02-17 14:04:47 +00:00
graphx [SPARK-34068][CORE][SQL][MLLIB][GRAPHX] Remove redundant collection conversion 2021-01-13 18:07:02 -06:00
hadoop-cloud [SPARK-33212][BUILD] Upgrade to Hadoop 3.2.2 and move to shaded clients for Hadoop 3.x profile 2021-01-15 14:06:50 -08:00
launcher [SPARK-33212][BUILD] Upgrade to Hadoop 3.2.2 and move to shaded clients for Hadoop 3.x profile 2021-01-15 14:06:50 -08:00
licenses [SPARK-32435][PYTHON] Remove heapq3 port from Python 3 2020-07-27 20:10:13 +09:00
licenses-binary [SPARK-32435][PYTHON] Remove heapq3 port from Python 3 2020-07-27 20:10:13 +09:00
mllib [SPARK-34080][ML][PYTHON][FOLLOW-UP] Update score function in UnivariateFeatureSelector document 2021-02-10 09:24:25 +09:00
mllib-local [SPARK-34068][CORE][SQL][MLLIB][GRAPHX] Remove redundant collection conversion 2021-01-13 18:07:02 -06:00
project [SPARK-34428][BUILD] Update sbt version to 1.4.7 2021-02-12 18:38:08 -08:00
python [SPARK-34433][DOCS] Lock Jekyll version by Gemfile and Bundler 2021-02-18 12:17:57 +09:00
R [SPARK-34306][SQL][PYTHON][R] Use Snake naming rule across the function APIs 2021-02-02 09:29:40 +09:00
repl [SPARK-33662][BUILD] Setting version to 3.2.0-SNAPSHOT 2020-12-04 14:10:42 -08:00
resource-managers [SPARK-33763] Add metrics for better tracking of dynamic allocation 2021-02-17 13:44:36 -08:00
sbin [SPARK-33984][PYTHON] Upgrade to Py4J 0.10.9.1 2021-01-04 10:23:38 -08:00
sql [SPARK-33739][SQL] Jobs committed through the S3A Magic committer don't track bytes 2021-02-18 08:43:18 -06:00
streaming [SPARK-34374][SQL][DSTREAM] Use standard methods to extract keys or values from a Map 2021-02-08 15:42:55 -06:00
tools [SPARK-33662][BUILD] Setting version to 3.2.0-SNAPSHOT 2020-12-04 14:10:42 -08:00
.asf.yaml [MINOR][INFRA] Update a broken link in .asf.yml 2021-01-16 13:42:27 -08:00
.gitattributes [SPARK-30653][INFRA][SQL] EOL character enforcement for java/scala/xml/py/R files 2020-01-27 10:20:51 -08:00
.gitignore [SPARK-34433][DOCS] Lock Jekyll version by Gemfile and Bundler 2021-02-18 12:17:57 +09:00
.sbtopts [SPARK-21708][BUILD] Migrate build to sbt 1.x 2020-10-07 15:28:00 -07:00
appveyor.yml [SPARK-33757][INFRA][R][FOLLOWUP] Provide more simple solution 2020-12-13 17:27:39 -08:00
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-32435][PYTHON] Remove heapq3 port from Python 3 2020-07-27 20:10:13 +09:00
LICENSE-binary [SPARK-33705][SQL][TEST] Fix HiveThriftHttpServerSuite flakiness 2020-12-14 05:14:38 +00:00
NOTICE [SPARK-29674][CORE] Update dropwizard metrics to 4.1.x for JDK 9+ 2019-11-03 15:13:06 -08:00
NOTICE-binary [SPARK-29674][CORE] Update dropwizard metrics to 4.1.x for JDK 9+ 2019-11-03 15:13:06 -08:00
pom.xml [SPARK-34449][BUILD] Upgrade Jetty to fix CVE-2020-27218 2021-02-18 18:02:34 +09:00
README.md [MINOR][DOCS] Fix Jenkins job badge image and link in README.md 2020-12-16 00:10:13 -08:00
scalastyle-config.xml [SPARK-32539][INFRA] Disallow FileSystem.get(Configuration conf) in style check by default 2020-08-06 05:56:59 +00:00

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.)

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.