Apache Spark - A unified analytics engine for large-scale data processing
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Max Gekk a03d77d326 [SPARK-33160][SQL][FOLLOWUP] Replace the parquet metadata key org.apache.spark.int96NoRebase by org.apache.spark.legacyINT96
### What changes were proposed in this pull request?
1. Replace the metadata key `org.apache.spark.int96NoRebase` by `org.apache.spark.legacyINT96`.
2. Change the condition when new key should be saved to parquet metadata: it should be saved when the SQL config `spark.sql.legacy.parquet.int96RebaseModeInWrite` is set to `LEGACY`.
3. Change handling the metadata key in read:
    - If there is no the key in parquet metadata, take the rebase mode from the SQL config: `spark.sql.legacy.parquet.int96RebaseModeInRead`
    - If parquet files were saved by Spark < 3.1.0, use the `LEGACY` rebasing mode for INT96 type.
    - For files written by Spark >= 3.1.0, if the `org.apache.spark.legacyINT96` presents in metadata, perform rebasing otherwise don't.

### Why are the changes needed?
- To not increase parquet size by default when `spark.sql.legacy.parquet.int96RebaseModeInWrite` is `EXCEPTION` after https://github.com/apache/spark/pull/30121.
- To have the implementation similar to `org.apache.spark.legacyDateTime`
- To minimise impact on other subsystems that are based on file sizes like gathering statistics.

### Does this PR introduce _any_ user-facing change?
No

### How was this patch tested?
Modified test in `ParquetIOSuite`

Closes #30132 from MaxGekk/int96-flip-metadata-rebase-key.

Authored-by: Max Gekk <max.gekk@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
2020-10-22 15:57:03 +00:00
.github [SPARK-33189][PYTHON][TESTS] Add env var to tests for legacy nested timestamps in pyarrow 2020-10-21 09:13:33 +09:00
assembly [SPARK-30950][BUILD] Setting version to 3.1.0-SNAPSHOT 2020-02-25 19:44:31 -08:00
bin [SPARK-32839][WINDOWS] Make Spark scripts working with the spaces in paths on Windows 2020-09-14 13:15:14 +09:00
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-21708][BUILD] Migrate build to sbt 1.x 2020-10-07 15:28:00 -07:00
common [SPARK-33212][BUILD] Move to shaded clients for Hadoop 3.x profile 2020-10-22 03:21:34 +00:00
conf [SPARK-32004][ALL] Drop references to slave 2020-07-13 14:05:33 -07:00
core [SPARK-33218][CORE] Update misleading log messages for removed shuffle blocks 2020-10-22 01:10:24 -07:00
data [SPARK-22666][ML][SQL] Spark datasource for image format 2018-09-05 11:59:00 -07:00
dev [SPARK-33212][BUILD] Move to shaded clients for Hadoop 3.x profile 2020-10-22 03:21:34 +00:00
docs [SPARK-33210][SQL] Set the rebasing mode for parquet INT96 type to EXCEPTION by default 2020-10-22 03:04:29 +00:00
examples [MINOR][DOCS][EXAMPLE] Fix the Python manual_load_options_csv example 2020-10-18 16:47:04 +09:00
external [SPARK-33095][SQL] Support ALTER TABLE in JDBC v2 Table Catalog: add, update type and nullability of columns (MySQL dialect) 2020-10-22 13:51:42 +00:00
graphx [SPARK-32398][TESTS][CORE][STREAMING][SQL][ML] Update to scalatest 3.2.0 for Scala 2.13.3+ 2020-07-23 16:20:17 -07:00
hadoop-cloud [SPARK-33212][BUILD] Move to shaded clients for Hadoop 3.x profile 2020-10-22 03:21:34 +00:00
launcher [SPARK-33212][BUILD] Move to shaded clients for Hadoop 3.x profile 2020-10-22 03:21:34 +00:00
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-33111][ML][FOLLOW-UP] aft transform optimization - predictQuantiles 2020-10-21 08:49:25 -05:00
mllib-local [SPARK-32907][ML] adaptively blockify instances - revert blockify gmm 2020-09-23 15:54:56 +08:00
project [SPARK-33109][BUILD][FOLLOW-UP] Remove the obsolete comment about bringing sbt-dependency-graph back 2020-10-18 09:24:44 -07:00
python [SPARK-33203][PYTHON][TEST] Fix tests failing with rounding errors 2020-10-21 18:14:21 -07:00
R [SPARK-13860][SQL] Change statistical aggregate function to return null instead of Double.NaN when divideByZero 2020-10-13 13:21:45 +00:00
repl [SPARK-30090][SHELL] Adapt Spark REPL to Scala 2.13 2020-09-12 18:15:15 -05:00
resource-managers [SPARK-33212][BUILD] Move to shaded clients for Hadoop 3.x profile 2020-10-22 03:21:34 +00:00
sbin [MINOR][DOCS] fix typo for docs,log message and comments 2020-08-22 06:45:35 +09:00
sql [SPARK-33160][SQL][FOLLOWUP] Replace the parquet metadata key org.apache.spark.int96NoRebase by org.apache.spark.legacyINT96 2020-10-22 15:57:03 +00:00
streaming [SPARK-32964][DSTREAMS] Pass all streaming module UTs in Scala 2.13 2020-09-22 11:01:44 -07:00
tools [SPARK-21708][BUILD] Migrate build to sbt 1.x 2020-10-07 15:28:00 -07:00
.asf.yaml [SPARK-31352] Add .asf.yaml to control Github settings 2020-04-06 09:06:01 -05:00
.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-17333][PYSPARK] Enable mypy 2020-10-19 12:50:01 -07:00
.sbtopts [SPARK-21708][BUILD] Migrate build to sbt 1.x 2020-10-07 15:28:00 -07:00
appveyor.yml [SPARK-32647][INFRA] Report SparkR test results with JUnit reporter 2020-08-18 19:35:15 +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-32435][PYTHON] Remove heapq3 port from Python 3 2020-07-27 20:10:13 +09:00
LICENSE-binary [SPARK-32435][PYTHON] Remove heapq3 port from Python 3 2020-07-27 20:10:13 +09:00
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-33212][BUILD] Move to shaded clients for Hadoop 3.x profile 2020-10-22 03:21:34 +00:00
README.md [MINOR][DOCS] Fix Jenkins build image and link in README.md 2020-01-20 23:08:24 -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.