## What changes were proposed in this pull request?

Update doc for R, programming guide. Clarify default behavior for all languages.

## How was this patch tested?

manually

Author: Felix Cheung <felixcheung_m@hotmail.com>

Closes #17128 from felixcheung/jsonwholefiledoc.

## What changes were proposed in this pull request?
Updates the doc string to match up with the code
i.e. say dropLast instead of includeFirst

## How was this patch tested?
Not much, since it's a doc-like change. Will run unit tests via Jenkins job.

Author: Mark Grover <mark@apache.org>

Closes #17127 from markgrover/spark_19734.

## What changes were proposed in this pull request?
Remove `org.apache.spark.examples.` in
Add slash in one of the python doc.

## How was this patch tested?
Run examples using the commands in the comments.

Author: Yun Ni <yunn@uber.com>

Closes #17104 from Yunni/yunn_minor.

## What changes were proposed in this pull request?

This PR proposes the support for multiple lines for CSV by resembling the multiline supports in JSON datasource (in case of JSON, per file).

So, this PR introduces `wholeFile` option which makes the format not splittable and reads each whole file. Since Univocity parser can produces each row from a stream, it should be capable of parsing very large documents when the internal rows are fix in the memory.

## How was this patch tested?

Unit tests in `CSVSuite` and `tests.py`

Manual tests with a single 9GB CSV file in local file system, for example,

```scala
spark.read.option("wholeFile", true).option("inferSchema", true).csv("tmp.csv").count()
```

Author: hyukjinkwon <gurwls223@gmail.com>

Closes #16976 from HyukjinKwon/SPARK-19610.

This PR adds a param to `ALS`/`ALSModel` to set the strategy used when encountering unknown users or items at prediction time in `transform`. This can occur in 2 scenarios: (a) production scoring, and (b) cross-validation & evaluation.

The current behavior returns `NaN` if a user/item is unknown. In scenario (b), this can easily occur when using `CrossValidator` or `TrainValidationSplit` since some users/items may only occur in the test set and not in the training set. In this case, the evaluator returns `NaN` for all metrics, making model selection impossible.

The new param, `coldStartStrategy`, defaults to `nan` (the current behavior). The other option supported initially is `drop`, which drops all rows with `NaN` predictions. This flag allows users to use `ALS` in cross-validation settings. It is made an `expertParam`. The param is made a string so that the set of strategies can be extended in future (some options are discussed in [SPARK-14489](https://issues.apache.org/jira/browse/SPARK-14489)).
## How was this patch tested?

New unit tests, and manual "before and after" tests for Scala & Python using MovieLens `ml-latest-small` as example data. Here, using `CrossValidator` or `TrainValidationSplit` with the default param setting results in metrics that are all `NaN`, while setting `coldStartStrategy` to `drop` results in valid metrics.

Author: Nick Pentreath <nickp@za.ibm.com>

Closes #12896 from MLnick/SPARK-14489-als-nan.

[SPARK-19660][CORE][SQL] Replace the configuration property names that are deprecated in the version of Hadoop 2.6

## What changes were proposed in this pull request?

Replace all the Hadoop deprecated configuration property names according to [DeprecatedProperties](https://hadoop.apache.org/docs/r2.6.0/hadoop-project-dist/hadoop-common/DeprecatedProperties.html).

except:
https://github.com/apache/spark/blob/v2.1.0/python/pyspark/sql/tests.py#L1533
https://github.com/apache/spark/blob/v2.1.0/sql/core/src/test/scala/org/apache/spark/sql/SQLQuerySuite.scala#L987
https://github.com/apache/spark/blob/v2.1.0/sql/core/src/main/scala/org/apache/spark/sql/execution/command/SetCommand.scala#L45
https://github.com/apache/spark/blob/v2.1.0/sql/core/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala#L614

## How was this patch tested?

Existing tests

Author: Yuming Wang <wgyumg@gmail.com>

Closes #16990 from wangyum/HadoopDeprecatedProperties.

## What changes were proposed in this pull request?
self.environment will be propagated to executor. Should set PYTHONHASHSEED as long as the python version is greater than 3.3

## How was this patch tested?
Manually tested it.

Author: Jeff Zhang <zjffdu@apache.org>

Closes #11211 from zjffdu/SPARK-13330.

## What changes were proposed in this pull request?

Replaces `UserDefinedFunction` object returned from `udf` with a function wrapper providing docstring and arguments information as proposed in [SPARK-19161](https://issues.apache.org/jira/browse/SPARK-19161).

### Backward incompatible changes:

- `pyspark.sql.functions.udf` will return a `function` instead of `UserDefinedFunction`. To ensure backward compatible public API we use function attributes to mimic  `UserDefinedFunction` API (`func` and `returnType` attributes).  This should have a minimal impact on the user code.

  An alternative implementation could use dynamical sub-classing. This would ensure full backward compatibility but is more fragile in practice.

### Limitations:

Full functionality (retained docstring and argument list) is achieved only in the recent Python version. Legacy Python version will preserve only docstrings, but not argument list. This should be an acceptable trade-off between achieved improvements and overall complexity.

### Possible impact on other tickets:

This can affect [SPARK-18777](https://issues.apache.org/jira/browse/SPARK-18777).

## How was this patch tested?

Existing unit tests to ensure backward compatibility, additional tests targeting proposed changes.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16534 from zero323/SPARK-19161.

## What changes were proposed in this pull request?
Fixed the PySpark Params.copy method to behave like the Scala implementation.  The main issue was that it did not account for the _defaultParamMap and merged it into the explicitly created param map.

## How was this patch tested?
Added new unit test to verify the copy method behaves correctly for copying uid, explicitly created params, and default params.

Author: Bryan Cutler <cutlerb@gmail.com>

Closes #16772 from BryanCutler/pyspark-ml-param_copy-Scala_sync-SPARK-14772.

## What changes were proposed in this pull request?

to be consistent with the scala API, we should also add `contains` to `Column` in pyspark.

## How was this patch tested?

updated unit test

Author: Wenchen Fan <wenchen@databricks.com>

Closes #17036 from cloud-fan/pyspark.

## What changes were proposed in this pull request?
This pr added a logic to put malformed tokens into a new field when parsing CSV data  in case of permissive modes. In the current master, if the CSV parser hits these malformed ones, it throws an exception below (and then a job fails);
```
Caused by: java.lang.IllegalArgumentException
	at java.sql.Date.valueOf(Date.java:143)
	at org.apache.spark.sql.catalyst.util.DateTimeUtils$.stringToTime(DateTimeUtils.scala:137)
	at org.apache.spark.sql.execution.datasources.csv.CSVTypeCast$$anonfun$castTo$6.apply$mcJ$sp(CSVInferSchema.scala:272)
	at org.apache.spark.sql.execution.datasources.csv.CSVTypeCast$$anonfun$castTo$6.apply(CSVInferSchema.scala:272)
	at org.apache.spark.sql.execution.datasources.csv.CSVTypeCast$$anonfun$castTo$6.apply(CSVInferSchema.scala:272)
	at scala.util.Try.getOrElse(Try.scala:79)
	at org.apache.spark.sql.execution.datasources.csv.CSVTypeCast$.castTo(CSVInferSchema.scala:269)
	at
```
In case that users load large CSV-formatted data, the job failure makes users get some confused. So, this fix set NULL for original columns and put malformed tokens in a new field.

## How was this patch tested?
Added tests in `CSVSuite`.

Author: Takeshi Yamamuro <yamamuro@apache.org>

Closes #16928 from maropu/SPARK-18699-2.

## What changes were proposed in this pull request?

This PR adds a special streaming deduplication operator to support `dropDuplicates` with `aggregation` and watermark. It reuses the `dropDuplicates` API but creates new logical plan `Deduplication` and new physical plan `DeduplicationExec`.

The following cases are supported:

- one or multiple `dropDuplicates()` without aggregation (with or without watermark)
- `dropDuplicates` before aggregation

Not supported cases:

- `dropDuplicates` after aggregation

Breaking changes:
- `dropDuplicates` without aggregation doesn't work with `complete` or `update` mode.

## How was this patch tested?

The new unit tests.

Author: Shixiong Zhu <shixiong@databricks.com>

Closes #16970 from zsxwing/dedup.

- Add dependency on aws-java-sdk-sts
- Replace SerializableAWSCredentials with new SerializableCredentialsProvider interface
- Make KinesisReceiver take SerializableCredentialsProvider as argument and
  pass credential provider to KCL
- Add new implementations of KinesisUtils.createStream() that take STS
  arguments
- Make JavaKinesisStreamSuite test the entire KinesisUtils Java API
- Update KCL/AWS SDK dependencies to 1.7.x/1.11.x

## What changes were proposed in this pull request?

[JIRA link with detailed description.](https://issues.apache.org/jira/browse/SPARK-19405)

* Replace SerializableAWSCredentials with new SerializableKCLAuthProvider class that takes 5 optional config params for configuring AWS auth and returns the appropriate credential provider object
* Add new public createStream() APIs for specifying these parameters in KinesisUtils

## How was this patch tested?

* Manually tested using explicit keypair and instance profile to read data from Kinesis stream in separate account (difficult to write a test orchestrating creation and assumption of IAM roles across separate accounts)
* Expanded JavaKinesisStreamSuite to test the entire Java API in KinesisUtils

## License acknowledgement
This contribution is my original work and that I license the work to the project under the project’s open source license.

Author: Budde <budde@amazon.com>

Closes #16744 from budde/master.

## What changes were proposed in this pull request?

Fix typo in docstring.

Author: Rolando Espinoza <rndmax84@gmail.com>

Closes #16967 from rolando/pyspark-doc-typo.

## What changes were proposed in this pull request?

If a new option `wholeFile` is set to `true` the JSON reader will parse each file (instead of a single line) as a value. This is done with Jackson streaming and it should be capable of parsing very large documents, assuming the row will fit in memory.

Because the file is not buffered in memory the corrupt record handling is also slightly different when `wholeFile` is enabled: the corrupt column will contain the filename instead of the literal JSON if there is a parsing failure. It would be easy to extend this to add the parser location (line, column and byte offsets) to the output if desired.

These changes have allowed types other than `String` to be parsed. Support for `UTF8String` and `Text` have been added (alongside `String` and `InputFormat`) and no longer require a conversion to `String` just for parsing.

I've also included a few other changes that generate slightly better bytecode and (imo) make it more obvious when and where boxing is occurring in the parser. These are included as separate commits, let me know if they should be flattened into this PR or moved to a new one.

## How was this patch tested?

New and existing unit tests. No performance or load tests have been run.

Author: Nathan Howell <nhowell@godaddy.com>

Closes #16386 from NathanHowell/SPARK-18352.

## What changes were proposed in this pull request?
This pull request includes python API and examples for LSH. The API changes was based on yanboliang 's PR #15768 and resolved conflicts and API changes on the Scala API. The examples are consistent with Scala examples of MinHashLSH and BucketedRandomProjectionLSH.

## How was this patch tested?
API and examples are tested using spark-submit:
`bin/spark-submit examples/src/main/python/ml/min_hash_lsh.py`
`bin/spark-submit examples/src/main/python/ml/bucketed_random_projection_lsh.py`

User guide changes are generated and manually inspected:
`SKIP_API=1 jekyll build`

Author: Yun Ni <yunn@uber.com>
Author: Yanbo Liang <ybliang8@gmail.com>
Author: Yunni <Euler57721@gmail.com>

Closes #16715 from Yunni/spark-18080.

## What changes were proposed in this pull request?
Right now, we only have info level log after we finish the tests of a Python test file. We should also log the start of a test. So, if a test is hanging, we can tell which test file is running.

## How was this patch tested?
This is a change for python tests.

Author: Yin Huai <yhuai@databricks.com>

Closes #16935 from yhuai/SPARK-19604.

## What changes were proposed in this pull request?

This is a follow-up pr of #16308.

This pr enables timezone support in CSV/JSON parsing.

We should introduce `timeZone` option for CSV/JSON datasources (the default value of the option is session local timezone).

The datasources should use the `timeZone` option to format/parse to write/read timestamp values.
Notice that while reading, if the timestampFormat has the timezone info, the timezone will not be used because we should respect the timezone in the values.

For example, if you have timestamp `"2016-01-01 00:00:00"` in `GMT`, the values written with the default timezone option, which is `"GMT"` because session local timezone is `"GMT"` here, are:

```scala
scala> spark.conf.set("spark.sql.session.timeZone", "GMT")

scala> val df = Seq(new java.sql.Timestamp(1451606400000L)).toDF("ts")
df: org.apache.spark.sql.DataFrame = [ts: timestamp]

scala> df.show()
+-------------------+
|ts                 |
+-------------------+
|2016-01-01 00:00:00|
+-------------------+

scala> df.write.json("/path/to/gmtjson")
```

```sh
$ cat /path/to/gmtjson/part-*
{"ts":"2016-01-01T00:00:00.000Z"}
```

whereas setting the option to `"PST"`, they are:

```scala
scala> df.write.option("timeZone", "PST").json("/path/to/pstjson")
```

```sh
$ cat /path/to/pstjson/part-*
{"ts":"2015-12-31T16:00:00.000-08:00"}
```

We can properly read these files even if the timezone option is wrong because the timestamp values have timezone info:

```scala
scala> val schema = new StructType().add("ts", TimestampType)
schema: org.apache.spark.sql.types.StructType = StructType(StructField(ts,TimestampType,true))

scala> spark.read.schema(schema).json("/path/to/gmtjson").show()
+-------------------+
|ts                 |
+-------------------+
|2016-01-01 00:00:00|
+-------------------+

scala> spark.read.schema(schema).option("timeZone", "PST").json("/path/to/gmtjson").show()
+-------------------+
|ts                 |
+-------------------+
|2016-01-01 00:00:00|
+-------------------+
```

And even if `timezoneFormat` doesn't contain timezone info, we can properly read the values with setting correct timezone option:

```scala
scala> df.write.option("timestampFormat", "yyyy-MM-dd'T'HH:mm:ss").option("timeZone", "JST").json("/path/to/jstjson")
```

```sh
$ cat /path/to/jstjson/part-*
{"ts":"2016-01-01T09:00:00"}
```

```scala
// wrong result
scala> spark.read.schema(schema).option("timestampFormat", "yyyy-MM-dd'T'HH:mm:ss").json("/path/to/jstjson").show()
+-------------------+
|ts                 |
+-------------------+
|2016-01-01 09:00:00|
+-------------------+

// correct result
scala> spark.read.schema(schema).option("timestampFormat", "yyyy-MM-dd'T'HH:mm:ss").option("timeZone", "JST").json("/path/to/jstjson").show()
+-------------------+
|ts                 |
+-------------------+
|2016-01-01 00:00:00|
+-------------------+
```

This pr also makes `JsonToStruct` and `StructToJson` `TimeZoneAwareExpression` to be able to evaluate values with timezone option.

## How was this patch tested?

Existing tests and added some tests.

Author: Takuya UESHIN <ueshin@happy-camper.st>

Closes #16750 from ueshin/issues/SPARK-18937.

## What changes were proposed in this pull request?

Add coalesce on DataFrame for down partitioning without shuffle and coalesce on Column

## How was this patch tested?

manual, unit tests

Author: Felix Cheung <felixcheung_m@hotmail.com>

Closes #16739 from felixcheung/rcoalesce.

## What changes were proposed in this pull request?

This PR adds `udf` decorator syntax as proposed in [SPARK-19160](https://issues.apache.org/jira/browse/SPARK-19160).

This allows users to define UDF using simplified syntax:

```python
from pyspark.sql.decorators import udf

udf(IntegerType())
def add_one(x):
    """Adds one"""
    if x is not None:
        return x + 1
 ```

without need to define a separate function and udf.

## How was this patch tested?

Existing unit tests to ensure backward compatibility and additional unit tests covering new functionality.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16533 from zero323/SPARK-19160.

## What changes were proposed in this pull request?
This PR is to document the changes on QuantileDiscretizer in pyspark for PR:
https://github.com/apache/spark/pull/15428

## How was this patch tested?
No test needed

Signed-off-by: VinceShieh <vincent.xieintel.com>

Author: VinceShieh <vincent.xie@intel.com>

Closes #16922 from VinceShieh/spark-19590.

## What changes were proposed in this pull request?

Add a `metadata` keyword parameter to `pyspark.sql.Column.alias()` to allow users to mix-in metadata while manipulating `DataFrame`s in `pyspark`.  Without this, I believe it was necessary to pass back through `SparkSession.createDataFrame` each time a user wanted to manipulate `StructField.metadata` in `pyspark`.

This pull request also improves consistency between the Scala and Python APIs (i.e. I did not add any functionality that was not already in the Scala API).

Discussed ahead of time on JIRA with marmbrus

## How was this patch tested?

Added unit tests (and doc tests).  Ran the pertinent tests manually.

Author: Sheamus K. Parkes <shea.parkes@milliman.com>

Closes #16094 from shea-parkes/pyspark-column-alias-metadata.

## What changes were proposed in this pull request?

UDF constructor checks if `func` argument is callable and if it is not, fails fast instead of waiting for an action.

## How was this patch tested?

Unit tests.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16535 from zero323/SPARK-19162.

## What changes were proposed in this pull request?

- Provides correct description of the semantics of a `dict` argument passed as `to_replace`.
- Describes type requirements for collection arguments.
- Describes behavior with `to_replace: List[T]` and `value: T`

## How was this patch tested?

Manual testing, documentation build.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16792 from zero323/SPARK-19453.

## What changes were proposed in this pull request?

- Add support for `slice` arguments in `Column.__getitem__`.
- Remove obsolete `__getslice__` bindings.

## How was this patch tested?

Existing unit tests, additional tests covering `[]` with `slice`.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16771 from zero323/SPARK-19429.

## What changes were proposed in this pull request?

Add support for data type string as a return type argument of `UserDefinedFunction`:

```python
f = udf(lambda x: x, "integer")
 f.returnType

## IntegerType
```

## How was this patch tested?

Existing unit tests, additional unit tests covering new feature.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16769 from zero323/SPARK-19427.

## What changes were proposed in this pull request?

Add missing `warnings` import.

## How was this patch tested?

Manual tests.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16846 from zero323/SPARK-19506.

## What changes were proposed in this pull request?

This pull request adds two new user facing functions:
- `to_date` which accepts an expression and a format and returns a date.
- `to_timestamp` which accepts an expression and a format and returns a timestamp.

For example, Given a date in format: `2016-21-05`. (YYYY-dd-MM)

### Date Function
*Previously*
```
to_date(unix_timestamp(lit("2016-21-05"), "yyyy-dd-MM").cast("timestamp"))
```
*Current*
```
to_date(lit("2016-21-05"), "yyyy-dd-MM")
```

### Timestamp Function
*Previously*
```
unix_timestamp(lit("2016-21-05"), "yyyy-dd-MM").cast("timestamp")
```
*Current*
```
to_timestamp(lit("2016-21-05"), "yyyy-dd-MM")
```
### Tasks

- [X] Add `to_date` to Scala Functions
- [x] Add `to_date` to Python Functions
- [x] Add `to_date` to SQL Functions
- [X] Add `to_timestamp` to Scala Functions
- [x] Add `to_timestamp` to Python Functions
- [x] Add `to_timestamp` to SQL Functions
- [x] Add function to R

## How was this patch tested?

- [x] Add Functions to `DateFunctionsSuite`
- Test new `ParseToTimestamp` Expression (*not necessary*)
- Test new `ParseToDate` Expression (*not necessary*)
- [x] Add test for R
- [x] Add test for Python in test.py

Please review http://spark.apache.org/contributing.html before opening a pull request.

Author: anabranch <wac.chambers@gmail.com>
Author: Bill Chambers <bill@databricks.com>
Author: anabranch <bill@databricks.com>

Closes #16138 from anabranch/SPARK-16609.

## What changes were proposed in this pull request?

Remove cyclic imports between `pyspark.ml.pipeline` and `pyspark.ml`.

## How was this patch tested?

Existing unit tests.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16814 from zero323/SPARK-19467.

## What changes were proposed in this pull request?
Methods `numClasses` and `numFeatures` in LinearSVCModel are already usable by inheriting `JavaClassificationModel`
we should not explicitly add them.

## How was this patch tested?
existing tests

Author: Zheng RuiFeng <ruifengz@foxmail.com>

Closes #16727 from zhengruifeng/nits_in_linearSVC.

## What changes were proposed in this pull request?

* Removed Since tags in Python Params since they are inherited by other classes
* Fixed doc links for LinearSVC

## How was this patch tested?

* doc tests
* generating docs locally and checking manually

Author: Joseph K. Bradley <joseph@databricks.com>

Closes #16723 from jkbradley/pyparam-fix-doc.

## What changes were proposed in this pull request?

1, add the multi-cols support based on current private api
2, add the multi-cols support to pyspark
## How was this patch tested?

unit tests

Author: Zheng RuiFeng <ruifengz@foxmail.com>
Author: Ruifeng Zheng <ruifengz@foxmail.com>

Closes #12135 from zhengruifeng/quantile4multicols.

## What changes were proposed in this pull request?

Defer `UserDefinedFunction._judf` initialization to the first call. This prevents unintended `SparkSession` initialization.  This allows users to define and import UDF without creating a context / session as a side effect.

[SPARK-19163](https://issues.apache.org/jira/browse/SPARK-19163)

## How was this patch tested?

Unit tests.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16536 from zero323/SPARK-19163.

[SPARK-17161][PYSPARK][ML] Add PySpark-ML JavaWrapper convenience function to create Py4J JavaArrays

## What changes were proposed in this pull request?

Adding convenience function to Python `JavaWrapper` so that it is easy to create a Py4J JavaArray that is compatible with current class constructors that have a Scala `Array` as input so that it is not necessary to have a Java/Python friendly constructor.  The function takes a Java class as input that is used by Py4J to create the Java array of the given class.  As an example, `OneVsRest` has been updated to use this and the alternate constructor is removed.

## How was this patch tested?

Added unit tests for the new convenience function and updated `OneVsRest` doctests which use this to persist the model.

Author: Bryan Cutler <cutlerb@gmail.com>

Closes #14725 from BryanCutler/pyspark-new_java_array-CountVectorizer-SPARK-17161.

## What changes were proposed in this pull request?

This removes from the `__all__` list class names that are not defined (visible) in the `pyspark.sql.column`.

## How was this patch tested?

Existing unit tests.

Author: zero323 <zero323@users.noreply.github.com>

Closes #16742 from zero323/SPARK-19403.

## What changes were proposed in this pull request?

Add Python API for the newly added LinearSVC algorithm.

## How was this patch tested?

Add new doc string test.

Author: wm624@hotmail.com <wm624@hotmail.com>

Closes #16694 from wangmiao1981/ser.

## What changes were proposed in this pull request?
This pr is to fix an issue occurred when resharding Kinesis streams; the resharding makes the KCL throw an exception because Spark does not checkpoint `SHARD_END` when finishing reading closed shards in `KinesisRecordProcessor#shutdown`. This bug finally leads to stopping subscribing new split (or merged) shards.

## How was this patch tested?
Added a test in `KinesisStreamSuite` to check if it works well when splitting/merging shards.

Author: Takeshi YAMAMURO <linguin.m.s@gmail.com>

Closes #16213 from maropu/SPARK-18020.

## What changes were proposed in this pull request?

Fix instalation of mllib and ml sub components, and more eagerly cleanup cache files during test script & make-distribution.

## How was this patch tested?

Updated sanity test script to import mllib and ml sub-components.

Author: Holden Karau <holden@us.ibm.com>

Closes #16465 from holdenk/SPARK-19064-fix-pip-install-sub-components.

The code was failing to propagate the user conf in the case where the
JVM was already initialized, which happens when a user submits a
python script via spark-submit.

Tested with new unit test and by running a python script in a real cluster.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #16682 from vanzin/SPARK-19307.

### What changes were proposed in this pull request?
It is weird to create Hive source tables when using InMemoryCatalog. We are unable to operate it. This PR is to block users to create Hive source tables.

### How was this patch tested?
Fixed the test cases

Author: gatorsmile <gatorsmile@gmail.com>

Closes #16587 from gatorsmile/blockHiveTable.