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935 commits

Author SHA1 Message Date
Alex Favaro 96c1a4401d [SPARK-30856][SQL][PYSPARK] Fix SQLContext.getOrCreate() when SparkContext is restarted
### What changes were proposed in this pull request?

As discussed on the Jira ticket, this change clears the SQLContext._instantiatedContext class attribute when the SparkSession is stopped. That way, the attribute will be reset with a new, usable SQLContext when a new SparkSession is started.

### Why are the changes needed?

When the underlying SQLContext is instantiated for a SparkSession, the instance is saved as a class attribute and returned from subsequent calls to SQLContext.getOrCreate(). If the SparkContext is stopped and a new one started, the SQLContext class attribute is never cleared so any code which calls SQLContext.getOrCreate() will get a SQLContext with a reference to the old, unusable SparkContext.

A similar issue was identified and fixed for SparkSession in [SPARK-19055](https://issues.apache.org/jira/browse/SPARK-19055), but the fix did not change SQLContext as well. I ran into this because mllib still [uses](https://github.com/apache/spark/blob/master/python/pyspark/mllib/common.py#L105) SQLContext.getOrCreate() under the hood.

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

No

### How was this patch tested?

A new test was added. I verified that the test fails without the included change.

Closes #27610 from afavaro/restart-sqlcontext.

Authored-by: Alex Favaro <alex.favaro@affirm.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-02-20 12:21:24 +09:00
HyukjinKwon e065e22e5e [SPARK-30861][PYTHON][SQL] Deprecate constructor of SQLContext and getOrCreate in SQLContext at PySpark
### What changes were proposed in this pull request?

This PR proposes to deprecate the APIs at `SQLContext` removed in SPARK-25908. We should remove equivalent APIs; however, seems we missed to deprecate.

While I am here, I fix one more issue. After SPARK-25908, `sc._jvm.SQLContext.getOrCreate` dose not exist anymore. So,

```python
from pyspark.sql import SQLContext
from pyspark import SparkContext
sc = SparkContext.getOrCreate()
SQLContext.getOrCreate(sc).range(10).show()
```

throws an exception as below:

```
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/.../spark/python/pyspark/sql/context.py", line 110, in getOrCreate
    jsqlContext = sc._jvm.SQLContext.getOrCreate(sc._jsc.sc())
  File "/.../spark/python/lib/py4j-0.10.8.1-src.zip/py4j/java_gateway.py", line 1516, in __getattr__
py4j.protocol.Py4JError: org.apache.spark.sql.SQLContext.getOrCreate does not exist in the JVM
```

After this PR:

```
/.../spark/python/pyspark/sql/context.py:113: DeprecationWarning: Deprecated in 3.0.0. Use SparkSession.builder.getOrCreate() instead.
  DeprecationWarning)
+---+
| id|
+---+
|  0|
|  1|
|  2|
|  3|
|  4|
|  5|
|  6|
|  7|
|  8|
|  9|
+---+
```

In case of the constructor of `SQLContext`, after this PR:

```python
from pyspark.sql import SQLContext
sc = SparkContext.getOrCreate()
SQLContext(sc)
```

```
/.../spark/python/pyspark/sql/context.py:77: DeprecationWarning: Deprecated in 3.0.0. Use SparkSession.builder.getOrCreate() instead.
  DeprecationWarning)
```

### Why are the changes needed?

To promote to use SparkSession, and keep the API party consistent with Scala side.

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

Yes, it will show deprecation warning to users.

### How was this patch tested?

Manually tested as described above. Unittests were also added.

Closes #27614 from HyukjinKwon/SPARK-30861.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-02-19 11:17:47 +09:00
yi.wu 68d7edf949 [SPARK-30812][SQL][CORE] Revise boolean config name to comply with new config naming policy
### What changes were proposed in this pull request?

Revise below config names to comply with [new config naming policy](http://apache-spark-developers-list.1001551.n3.nabble.com/DISCUSS-naming-policy-of-Spark-configs-td28875.html):

SQL:
* spark.sql.execution.subquery.reuse.enabled / [SPARK-27083](https://issues.apache.org/jira/browse/SPARK-27083)
* spark.sql.legacy.allowNegativeScaleOfDecimal.enabled / [SPARK-30252](https://issues.apache.org/jira/browse/SPARK-30252)
* spark.sql.adaptive.optimizeSkewedJoin.enabled / [SPARK-29544](https://issues.apache.org/jira/browse/SPARK-29544)
* spark.sql.legacy.property.nonReserved / [SPARK-30183](https://issues.apache.org/jira/browse/SPARK-30183)
* spark.sql.streaming.forceDeleteTempCheckpointLocation.enabled / [SPARK-26389](https://issues.apache.org/jira/browse/SPARK-26389)
* spark.sql.analyzer.failAmbiguousSelfJoin.enabled / [SPARK-28344](https://issues.apache.org/jira/browse/SPARK-28344)
* spark.sql.adaptive.shuffle.reducePostShufflePartitions.enabled / [SPARK-30074](https://issues.apache.org/jira/browse/SPARK-30074)
* spark.sql.execution.pandas.arrowSafeTypeConversion / [SPARK-25811](https://issues.apache.org/jira/browse/SPARK-25811)
* spark.sql.legacy.looseUpcast / [SPARK-24586](https://issues.apache.org/jira/browse/SPARK-24586)
* spark.sql.legacy.arrayExistsFollowsThreeValuedLogic / [SPARK-28052](https://issues.apache.org/jira/browse/SPARK-28052)
* spark.sql.sources.ignoreDataLocality.enabled / [SPARK-29189](https://issues.apache.org/jira/browse/SPARK-29189)
* spark.sql.adaptive.shuffle.fetchShuffleBlocksInBatch.enabled / [SPARK-9853](https://issues.apache.org/jira/browse/SPARK-9853)

CORE:
* spark.eventLog.erasureCoding.enabled / [SPARK-25855](https://issues.apache.org/jira/browse/SPARK-25855)
* spark.shuffle.readHostLocalDisk.enabled / [SPARK-30235](https://issues.apache.org/jira/browse/SPARK-30235)
* spark.scheduler.listenerbus.logSlowEvent.enabled / [SPARK-29001](https://issues.apache.org/jira/browse/SPARK-29001)
* spark.resources.coordinate.enable / [SPARK-27371](https://issues.apache.org/jira/browse/SPARK-27371)
* spark.eventLog.logStageExecutorMetrics.enabled / [SPARK-23429](https://issues.apache.org/jira/browse/SPARK-23429)

### Why are the changes needed?

To comply with the config naming policy.

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

No. Configurations listed above are all newly added in Spark 3.0.

### How was this patch tested?

Pass Jenkins.

Closes #27563 from Ngone51/revise_boolean_conf_name.

Authored-by: yi.wu <yi.wu@databricks.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
2020-02-18 20:39:50 +08:00
David Toneian 504b5135d0 [SPARK-30859][PYSPARK][DOCS][MINOR] Fixed docstring syntax issues preventing proper compilation of documentation
This commit is published into the public domain.

### What changes were proposed in this pull request?
Some syntax issues in docstrings have been fixed.

### Why are the changes needed?
In some places, the documentation did not render as intended, e.g. parameter documentations were not formatted as such.

### Does this PR introduce any user-facing change?
Slight improvements in documentation.

### How was this patch tested?
Manual testing. No new Sphinx warnings arise due to this change.

Closes #27613 from DavidToneian/SPARK-30859.

Authored-by: David Toneian <david@toneian.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-02-18 16:46:45 +09:00
Liang Zhang d8c0599e54 [SPARK-30791][SQL][PYTHON] Add 'sameSemantics' and 'sementicHash' methods in Dataset
### What changes were proposed in this pull request?
This PR added two DeveloperApis to the Dataset[T] class. Both methods are just exposing lower-level methods to the Dataset[T] class.

### Why are the changes needed?
They are useful for checking whether two dataframes are the same when implementing dataframe caching in python, and also get a unique ID. It's easier to use if we wrap the lower-level APIs.

### Does this PR introduce any user-facing change?
```
scala> val df1 = Seq((1,2),(4,5)).toDF("col1", "col2")
df1: org.apache.spark.sql.DataFrame = [col1: int, col2: int]

scala> val df2 = Seq((1,2),(4,5)).toDF("col1", "col2")
df2: org.apache.spark.sql.DataFrame = [col1: int, col2: int]

scala> val df3 = Seq((0,2),(4,5)).toDF("col1", "col2")
df3: org.apache.spark.sql.DataFrame = [col1: int, col2: int]

scala> val df4 = Seq((0,2),(4,5)).toDF("col0", "col2")
df4: org.apache.spark.sql.DataFrame = [col0: int, col2: int]

scala> df1.semanticHash
res0: Int = 594427822

scala> df2.semanticHash
res1: Int = 594427822

scala> df1.sameSemantics(df2)
res2: Boolean = true

scala> df1.sameSemantics(df3)
res3: Boolean = false

scala> df3.semanticHash
res4: Int = -1592702048

scala> df4.semanticHash
res5: Int = -1592702048

scala> df4.sameSemantics(df3)
res6: Boolean = true
```

### How was this patch tested?
Unit test in scala and doctest in python.

Note: comments are copied from the corresponding lower-level APIs.
Note: There are some issues to be fixed that would improve the hash collision rate: https://github.com/apache/spark/pull/27565#discussion_r379881028

Closes #27565 from liangz1/df-same-result.

Authored-by: Liang Zhang <liang.zhang@databricks.com>
Signed-off-by: WeichenXu <weichen.xu@databricks.com>
2020-02-18 09:22:26 +08:00
Yuanjian Li ab186e3659 [SPARK-25829][SQL] Add config spark.sql.legacy.allowDuplicatedMapKeys and change the default behavior
### What changes were proposed in this pull request?
This is a follow-up for #23124, add a new config `spark.sql.legacy.allowDuplicatedMapKeys` to control the behavior of removing duplicated map keys in build-in functions. With the default value `false`, Spark will throw a RuntimeException while duplicated keys are found.

### Why are the changes needed?
Prevent silent behavior changes.

### Does this PR introduce any user-facing change?
Yes, new config added and the default behavior for duplicated map keys changed to RuntimeException thrown.

### How was this patch tested?
Modify existing UT.

Closes #27478 from xuanyuanking/SPARK-25892-follow.

Authored-by: Yuanjian Li <xyliyuanjian@gmail.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
2020-02-17 22:06:58 +08:00
David Toneian 25db8c71a2 [PYSPARK][DOCS][MINOR] Changed :func: to :attr: Sphinx roles, fixed links in documentation of Data{Frame,Stream}{Reader,Writer}
This commit is published into the public domain.

### What changes were proposed in this pull request?
This PR fixes the documentation of `DataFrameReader`, `DataFrameWriter`, `DataStreamReader`, and `DataStreamWriter`, where attributes of other classes were misrepresented as functions. Additionally, creation of hyperlinks across modules was fixed in these instances.

### Why are the changes needed?
The old state produced documentation that suggested invalid usage of PySpark objects (accessing attributes as though they were callable.)

### Does this PR introduce any user-facing change?
No, except for improved documentation.

### How was this patch tested?
No test added; documentation build runs through.

Closes #27553 from DavidToneian/docfix-DataFrameReader-DataFrameWriter-DataStreamReader-DataStreamWriter.

Authored-by: David Toneian <david@toneian.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-02-14 11:00:35 +09:00
HyukjinKwon aa6a60530e [SPARK-30722][PYTHON][DOCS] Update documentation for Pandas UDF with Python type hints
### What changes were proposed in this pull request?

This PR targets to document the Pandas UDF redesign with type hints introduced at SPARK-28264.
Mostly self-describing; however, there are few things to note for reviewers.

1. This PR replace the existing documentation of pandas UDFs to the newer redesign to promote the Python type hints. I added some words that Spark 3.0 still keeps the compatibility though.

2. This PR proposes to name non-pandas UDFs as "Pandas Function API"

3. SCALAR_ITER become two separate sections to reduce confusion:
  - `Iterator[pd.Series]` -> `Iterator[pd.Series]`
  - `Iterator[Tuple[pd.Series, ...]]` -> `Iterator[pd.Series]`

4. I removed some examples that look overkill to me.

5. I also removed some information in the doc, that seems duplicating or too much.

### Why are the changes needed?

To document new redesign in pandas UDF.

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

No.

### How was this patch tested?

Existing tests should cover.

Closes #27466 from HyukjinKwon/SPARK-30722.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-02-12 10:49:46 +09:00
Bryan Cutler 07a9885f27 [SPARK-30777][PYTHON][TESTS] Fix test failures for Pandas >= 1.0.0
### What changes were proposed in this pull request?

Fix PySpark test failures for using Pandas >= 1.0.0.

### Why are the changes needed?

Pandas 1.0.0 has recently been released and has API changes that result in PySpark test failures, this PR fixes the broken tests.

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

No

### How was this patch tested?

Manually tested with Pandas 1.0.1 and PyArrow 0.16.0

Closes #27529 from BryanCutler/pandas-fix-tests-1.0-SPARK-30777.

Authored-by: Bryan Cutler <cutlerb@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-02-11 10:03:01 +09:00
sharif ahmad dd2f4431f5 [MINOR][DOCS] Fix typos at python/pyspark/sql/types.py
### What changes were proposed in this pull request?

This PR fixes some typos in `python/pyspark/sql/types.py` file.

### Why are the changes needed?

To deliver correct wording in documentation and codes.

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

Yes, it fixes some typos in user-facing API documentation.

### How was this patch tested?

Locally tested the linter.

Closes #27475 from sharifahmad2061/master.

Lead-authored-by: sharif ahmad <sharifahmad2061@gmail.com>
Co-authored-by: Sharif ahmad <sharifahmad2061@users.noreply.github.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-02-07 18:42:16 +09:00
HyukjinKwon 692e3ddb4e [SPARK-27870][PYTHON][FOLLOW-UP] Rename spark.sql.pandas.udf.buffer.size to spark.sql.execution.pandas.udf.buffer.size
### What changes were proposed in this pull request?

This PR renames `spark.sql.pandas.udf.buffer.size` to `spark.sql.execution.pandas.udf.buffer.size` to be more consistent with other pandas configuration prefixes, given:
-  `spark.sql.execution.pandas.arrowSafeTypeConversion`
- `spark.sql.execution.pandas.respectSessionTimeZone`
- `spark.sql.legacy.execution.pandas.groupedMap.assignColumnsByName`
- other configurations like `spark.sql.execution.arrow.*`.

### Why are the changes needed?

To make configuration names consistent.

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

No because this configuration was not released yet.

### How was this patch tested?

Existing tests should cover.

Closes #27450 from HyukjinKwon/SPARK-27870-followup.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-02-05 11:38:33 +09:00
Bryan Cutler 43d9c7e7e5 [SPARK-30640][PYTHON][SQL] Prevent unnecessary copies of data during Arrow to Pandas conversion
### What changes were proposed in this pull request?

Prevent unnecessary copies of data during conversion from Arrow to Pandas.

### Why are the changes needed?

During conversion of pyarrow data to Pandas, columns are checked for timestamp types and then modified to correct for local timezone. If the data contains no timestamp types, then unnecessary copies of the data can be made. This is most prevalent when checking columns of a pandas DataFrame where each series is assigned back to the DataFrame, regardless if it had timestamps. See https://www.mail-archive.com/devarrow.apache.org/msg17008.html and ARROW-7596 for discussion.

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

No

### How was this patch tested?

Existing tests

Closes #27358 from BryanCutler/pyspark-pandas-timestamp-copy-fix-SPARK-30640.

Authored-by: Bryan Cutler <cutlerb@gmail.com>
Signed-off-by: Bryan Cutler <cutlerb@gmail.com>
2020-01-26 15:21:06 -08:00
Xiao Li d69ed9afdf Revert "[SPARK-25496][SQL] Deprecate from_utc_timestamp and to_utc_timestamp"
This reverts commit 1d20d13149.

Closes #27351 from gatorsmile/revertSPARK25496.

Authored-by: Xiao Li <gatorsmile@gmail.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2020-01-25 21:34:12 -08:00
Deepyaman Datta 53fd83a8c5 [MINOR][DOCS] Fix src/dest type documentation for to_timestamp
### What changes were proposed in this pull request?

Minor documentation fix

### Why are the changes needed?

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

### How was this patch tested?

Manually; consider adding tests?

Closes #27295 from deepyaman/patch-2.

Authored-by: Deepyaman Datta <deepyaman.datta@utexas.edu>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-01-24 13:10:09 +09:00
zero323 2330a5682d [SPARK-30607][SQL][PYSPARK][SPARKR] Add overlay wrappers for SparkR and PySpark
### What changes were proposed in this pull request?

This PR adds:

- `pyspark.sql.functions.overlay` function to PySpark
- `overlay` function to SparkR

### Why are the changes needed?

Feature parity. At the moment R and Python users can access this function only using SQL or `expr` / `selectExpr`.

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

No.

### How was this patch tested?

New unit tests.

Closes #27325 from zero323/SPARK-30607.

Authored-by: zero323 <mszymkiewicz@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-01-23 16:16:47 +09:00
HyukjinKwon ab0890bdb1 [SPARK-28264][PYTHON][SQL] Support type hints in pandas UDF and rename/move inconsistent pandas UDF types
### What changes were proposed in this pull request?

This PR proposes to redesign pandas UDFs as described in [the proposal](https://docs.google.com/document/d/1-kV0FS_LF2zvaRh_GhkV32Uqksm_Sq8SvnBBmRyxm30/edit?usp=sharing).

```python
from pyspark.sql.functions import pandas_udf
import pandas as pd

pandas_udf("long")
def plug_one(s: pd.Series) -> pd.Series:
    return s + 1

spark.range(10).select(plug_one("id")).show()
```

```
+------------+
|plug_one(id)|
+------------+
|           1|
|           2|
|           3|
|           4|
|           5|
|           6|
|           7|
|           8|
|           9|
|          10|
+------------+
```

Note that, this PR address one of the future improvements described [here](https://docs.google.com/document/d/1-kV0FS_LF2zvaRh_GhkV32Uqksm_Sq8SvnBBmRyxm30/edit#heading=h.h3ncjpk6ujqu), "A couple of less-intuitive pandas UDF types" (by zero323) together.

In short,

- Adds new way with type hints as an alternative and experimental way.
    ```python
    pandas_udf(schema='...')
    def func(c1: Series, c2: Series) -> DataFrame:
        pass
    ```

- Replace and/or add an alias for three types below from UDF, and make them as separate standalone APIs. So, `pandas_udf` is now consistent with regular `udf`s and other expressions.

    `df.mapInPandas(udf)`  -replace-> `df.mapInPandas(f, schema)`
    `df.groupby.apply(udf)`  -alias-> `df.groupby.applyInPandas(f, schema)`
    `df.groupby.cogroup.apply(udf)`  -replace-> `df.groupby.cogroup.applyInPandas(f, schema)`

    *`df.groupby.apply` was added from 2.3 while the other were added in the master only.

- No deprecation for the existing ways for now.
    ```python
    pandas_udf(schema='...', functionType=PandasUDFType.SCALAR)
    def func(c1, c2):
        pass
    ```
If users are happy with this, I plan to deprecate the existing way and declare using type hints is not experimental anymore.

One design goal in this PR was that, avoid touching the internal (since we didn't deprecate the old ways for now), but supports type hints with a minimised changes only at the interface.

- Once we deprecate or remove the old ways, I think it requires another refactoring for the internal in the future. At the very least, we should rename internal pandas evaluation types.
- If users find this experimental type hints isn't quite helpful, we should simply revert the changes at the interface level.

### Why are the changes needed?

In order to address old design issues. Please see [the proposal](https://docs.google.com/document/d/1-kV0FS_LF2zvaRh_GhkV32Uqksm_Sq8SvnBBmRyxm30/edit?usp=sharing).

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

For behaviour changes, No.

It adds new ways to use pandas UDFs by using type hints. See below.

**SCALAR**:

```python
pandas_udf(schema='...')
def func(c1: Series, c2: DataFrame) -> Series:
    pass  # DataFrame represents a struct column
```

**SCALAR_ITER**:

```python
pandas_udf(schema='...')
def func(iter: Iterator[Tuple[Series, DataFrame, ...]]) -> Iterator[Series]:
    pass  # Same as SCALAR but wrapped by Iterator
```

**GROUPED_AGG**:

```python
pandas_udf(schema='...')
def func(c1: Series, c2: DataFrame) -> int:
    pass  # DataFrame represents a struct column
```

**GROUPED_MAP**:

This was added in Spark 2.3 as of SPARK-20396. As described above, it keeps the existing behaviour. Additionally, we now have a new alias `groupby.applyInPandas` for `groupby.apply`. See the example below:

```python
def func(pdf):
    return pdf

df.groupby("...").applyInPandas(func, schema=df.schema)
```

**MAP_ITER**: this is not a pandas UDF anymore

This was added in Spark 3.0 as of SPARK-28198; and this PR replaces the usages. See the example below:

```python
def func(iter):
    for df in iter:
        yield df

df.mapInPandas(func, df.schema)
```

**COGROUPED_MAP**: this is not a pandas UDF anymore

This was added in Spark 3.0 as of SPARK-27463; and this PR replaces the usages. See the example below:

```python
def asof_join(left, right):
    return pd.merge_asof(left, right, on="...", by="...")

 df1.groupby("...").cogroup(df2.groupby("...")).applyInPandas(asof_join, schema="...")
```

### How was this patch tested?

Unittests added and tested against Python 2.7, 3.6 and 3.7.

Closes #27165 from HyukjinKwon/revisit-pandas.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-01-22 15:32:58 +09:00
yi.wu ff39c9271c [SPARK-30252][SQL] Disallow negative scale of Decimal
### What changes were proposed in this pull request?

This PR propose to disallow negative `scale` of `Decimal` in Spark. And this PR brings two behavior changes:

1) for literals like `1.23E4BD` or `1.23E4`(with `spark.sql.legacy.exponentLiteralAsDecimal.enabled`=true, see [SPARK-29956](https://issues.apache.org/jira/browse/SPARK-29956)), we set its `(precision, scale)` to (5, 0) rather than (3, -2);
2) add negative `scale` check inside the decimal method if it exposes to set `scale` explicitly. If check fails, `AnalysisException` throws.

And user could still use `spark.sql.legacy.allowNegativeScaleOfDecimal.enabled` to restore the previous behavior.

### Why are the changes needed?

According to SQL standard,
> 4.4.2 Characteristics of numbers
An exact numeric type has a precision P and a scale S. P is a positive integer that determines the number of significant digits in a particular radix R, where R is either 2 or 10. S is a non-negative integer.

scale of Decimal should always be non-negative. And other mainstream databases, like Presto, PostgreSQL, also don't allow negative scale.

Presto:
```
presto:default> create table t (i decimal(2, -1));
Query 20191213_081238_00017_i448h failed: line 1:30: mismatched input '-'. Expecting: <integer>, <type>
create table t (i decimal(2, -1))
```

PostgrelSQL:
```
postgres=# create table t(i decimal(2, -1));
ERROR:  NUMERIC scale -1 must be between 0 and precision 2
LINE 1: create table t(i decimal(2, -1));
                         ^
```

And, actually, Spark itself already doesn't allow to create table with negative decimal types using SQL:
```
scala> spark.sql("create table t(i decimal(2, -1))");
org.apache.spark.sql.catalyst.parser.ParseException:
no viable alternative at input 'create table t(i decimal(2, -'(line 1, pos 28)

== SQL ==
create table t(i decimal(2, -1))
----------------------------^^^

  at org.apache.spark.sql.catalyst.parser.ParseException.withCommand(ParseDriver.scala:263)
  at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parse(ParseDriver.scala:130)
  at org.apache.spark.sql.execution.SparkSqlParser.parse(SparkSqlParser.scala:48)
  at org.apache.spark.sql.catalyst.parser.AbstractSqlParser.parsePlan(ParseDriver.scala:76)
  at org.apache.spark.sql.SparkSession.$anonfun$sql$1(SparkSession.scala:605)
  at org.apache.spark.sql.catalyst.QueryPlanningTracker.measurePhase(QueryPlanningTracker.scala:111)
  at org.apache.spark.sql.SparkSession.sql(SparkSession.scala:605)
  ... 35 elided
```

However, it is still possible to create such table or `DatFrame` using Spark SQL programming API:
```
scala> val tb =
 CatalogTable(
  TableIdentifier("test", None),
  CatalogTableType.MANAGED,
  CatalogStorageFormat.empty,
  StructType(StructField("i", DecimalType(2, -1) ) :: Nil))
```
```
scala> spark.sql("SELECT 1.23E4BD")
res2: org.apache.spark.sql.DataFrame = [1.23E+4: decimal(3,-2)]
```
while, these two different behavior could make user confused.

On the other side, even if user creates such table or `DataFrame` with negative scale decimal type, it can't write data out if using format, like `parquet` or `orc`. Because these formats have their own check for negative scale and fail on it.
```
scala> spark.sql("SELECT 1.23E4BD").write.saveAsTable("parquet")
19/12/13 17:37:04 ERROR Executor: Exception in task 0.0 in stage 0.0 (TID 0)
java.lang.IllegalArgumentException: Invalid DECIMAL scale: -2
	at org.apache.parquet.Preconditions.checkArgument(Preconditions.java:53)
	at org.apache.parquet.schema.Types$BasePrimitiveBuilder.decimalMetadata(Types.java:495)
	at org.apache.parquet.schema.Types$BasePrimitiveBuilder.build(Types.java:403)
	at org.apache.parquet.schema.Types$BasePrimitiveBuilder.build(Types.java:309)
	at org.apache.parquet.schema.Types$Builder.named(Types.java:290)
	at org.apache.spark.sql.execution.datasources.parquet.SparkToParquetSchemaConverter.convertField(ParquetSchemaConverter.scala:428)
	at org.apache.spark.sql.execution.datasources.parquet.SparkToParquetSchemaConverter.convertField(ParquetSchemaConverter.scala:334)
	at org.apache.spark.sql.execution.datasources.parquet.SparkToParquetSchemaConverter.$anonfun$convert$2(ParquetSchemaConverter.scala:326)
	at scala.collection.TraversableLike.$anonfun$map$1(TraversableLike.scala:238)
	at scala.collection.Iterator.foreach(Iterator.scala:941)
	at scala.collection.Iterator.foreach$(Iterator.scala:941)
	at scala.collection.AbstractIterator.foreach(Iterator.scala:1429)
	at scala.collection.IterableLike.foreach(IterableLike.scala:74)
	at scala.collection.IterableLike.foreach$(IterableLike.scala:73)
	at org.apache.spark.sql.types.StructType.foreach(StructType.scala:99)
	at scala.collection.TraversableLike.map(TraversableLike.scala:238)
	at scala.collection.TraversableLike.map$(TraversableLike.scala:231)
	at org.apache.spark.sql.types.StructType.map(StructType.scala:99)
	at org.apache.spark.sql.execution.datasources.parquet.SparkToParquetSchemaConverter.convert(ParquetSchemaConverter.scala:326)
	at org.apache.spark.sql.execution.datasources.parquet.ParquetWriteSupport.init(ParquetWriteSupport.scala:97)
	at org.apache.parquet.hadoop.ParquetOutputFormat.getRecordWriter(ParquetOutputFormat.java:388)
	at org.apache.parquet.hadoop.ParquetOutputFormat.getRecordWriter(ParquetOutputFormat.java:349)
	at org.apache.spark.sql.execution.datasources.parquet.ParquetOutputWriter.<init>(ParquetOutputWriter.scala:37)
	at org.apache.spark.sql.execution.datasources.parquet.ParquetFileFormat$$anon$1.newInstance(ParquetFileFormat.scala:150)
	at org.apache.spark.sql.execution.datasources.SingleDirectoryDataWriter.newOutputWriter(FileFormatDataWriter.scala:124)
	at org.apache.spark.sql.execution.datasources.SingleDirectoryDataWriter.<init>(FileFormatDataWriter.scala:109)
	at org.apache.spark.sql.execution.datasources.FileFormatWriter$.executeTask(FileFormatWriter.scala:264)
	at org.apache.spark.sql.execution.datasources.FileFormatWriter$.$anonfun$write$15(FileFormatWriter.scala:205)
	at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:90)
	at org.apache.spark.scheduler.Task.run(Task.scala:127)
	at org.apache.spark.executor.Executor$TaskRunner.$anonfun$run$3(Executor.scala:441)
	at org.apache.spark.util.Utils$.tryWithSafeFinally(Utils.scala:1377)
	at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:444)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
```

So, I think it would be better to disallow negative scale totally and make behaviors above be consistent.

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

Yes, if `spark.sql.legacy.allowNegativeScaleOfDecimal.enabled=false`, user couldn't create Decimal value with negative scale anymore.

### How was this patch tested?

Added new tests in `ExpressionParserSuite` and `DecimalSuite`;
Updated `SQLQueryTestSuite`.

Closes #26881 from Ngone51/nonnegative-scale.

Authored-by: yi.wu <yi.wu@databricks.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
2020-01-21 21:09:48 +08:00
HyukjinKwon a6bdea3ad4 [SPARK-30539][PYTHON][SQL] Add DataFrame.tail in PySpark
### What changes were proposed in this pull request?

https://github.com/apache/spark/pull/26809 added `Dataset.tail` API. It should be good to have it in PySpark API as well.

### Why are the changes needed?

To support consistent APIs.

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

No. It adds a new API.

### How was this patch tested?

Manually tested and doctest was added.

Closes #27251 from HyukjinKwon/SPARK-30539.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2020-01-18 00:18:12 -08:00
HyukjinKwon 1881caa95e [SPARK-29188][PYTHON][FOLLOW-UP] Explicitly disable Arrow execution for all test of toPandas empty types
### What changes were proposed in this pull request?

Another followup of 4398dfa709

I missed two more tests added:

```
======================================================================
ERROR [0.133s]: test_to_pandas_from_mixed_dataframe (pyspark.sql.tests.test_dataframe.DataFrameTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/jenkins/python/pyspark/sql/tests/test_dataframe.py", line 617, in test_to_pandas_from_mixed_dataframe
    self.assertTrue(np.all(pdf_with_only_nulls.dtypes == pdf_with_some_nulls.dtypes))
AssertionError: False is not true
======================================================================
ERROR [0.061s]: test_to_pandas_from_null_dataframe (pyspark.sql.tests.test_dataframe.DataFrameTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/jenkins/python/pyspark/sql/tests/test_dataframe.py", line 588, in test_to_pandas_from_null_dataframe
    self.assertEqual(types[0], np.float64)
AssertionError: dtype('O') != <class 'numpy.float64'>
----------------------------------------------------------------------
```

### Why are the changes needed?

To make the test independent of default values of configuration.

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

No.

### How was this patch tested?

Manually tested and Jenkins should test.

Closes #27250 from HyukjinKwon/SPARK-29188-followup2.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-01-17 15:00:18 +09:00
HyukjinKwon 4398dfa709 [SPARK-29188][PYTHON][FOLLOW-UP] Explicitly disable Arrow execution for the test of toPandas empty types
### What changes were proposed in this pull request?

This PR proposes to explicitly disable Arrow execution for the test of toPandas empty types. If `spark.sql.execution.arrow.pyspark.enabled` is enabled by default, this test alone fails as below:

```
======================================================================
ERROR [0.205s]: test_to_pandas_from_empty_dataframe (pyspark.sql.tests.test_dataframe.DataFrameTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/.../pyspark/sql/tests/test_dataframe.py", line 568, in test_to_pandas_from_empty_dataframe
    self.assertTrue(np.all(dtypes_when_empty_df == dtypes_when_nonempty_df))
AssertionError: False is not true
----------------------------------------------------------------------
```

it should be best to explicitly disable for the test that only works when it's disabled.

### Why are the changes needed?

To make the test independent of default values of configuration.

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

No.

### How was this patch tested?

Manually tested and Jenkins should test.

Closes #27247 from HyukjinKwon/SPARK-29188-followup.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2020-01-16 19:27:30 -08:00
Maxim Gekk 1a9de8c31f [SPARK-30499][SQL] Remove SQL config spark.sql.execution.pandas.respectSessionTimeZone
### What changes were proposed in this pull request?
In the PR, I propose to remove the SQL config `spark.sql.execution.pandas.respectSessionTimeZone` which has been deprecated since Spark 2.3.

### Why are the changes needed?
To improve code maintainability.

### Does this PR introduce any user-facing change?
Yes.

### How was this patch tested?
by running python tests, https://spark.apache.org/docs/latest/building-spark.html#pyspark-tests-with-maven-or-sbt

Closes #27218 from MaxGekk/remove-respectSessionTimeZone.

Authored-by: Maxim Gekk <max.gekk@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-01-17 11:44:49 +09:00
HyukjinKwon 0a95eb0800 [SPARK-30434][FOLLOW-UP][PYTHON][SQL] Make the parameter list consistent in createDataFrame
### What changes were proposed in this pull request?

This is a followup of https://github.com/apache/spark/pull/27109. It should match the parameter lists in `createDataFrame`.

### Why are the changes needed?

To pass parameters supposed to pass.

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

No (it's only in master)

### How was this patch tested?

Manually tested and existing tests should cover.

Closes #27225 from HyukjinKwon/SPARK-30434-followup.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-01-16 12:39:44 +09:00
jiake b389b8c5f0 [SPARK-30188][SQL] Resolve the failed unit tests when enable AQE
### What changes were proposed in this pull request?
Fix all the failed tests when enable AQE.

### Why are the changes needed?
Run more tests with AQE to catch bugs, and make it easier to enable AQE by default in the future.

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

### How was this patch tested?
Existing unit tests

Closes #26813 from JkSelf/enableAQEDefault.

Authored-by: jiake <ke.a.jia@intel.com>
Signed-off-by: Wenchen Fan <wenchen@databricks.com>
2020-01-13 22:55:19 +08:00
Bryan Cutler f372d1cf4f [SPARK-29748][PYTHON][SQL] Remove Row field sorting in PySpark for version 3.6+
### What changes were proposed in this pull request?

Removing the sorting of PySpark SQL Row fields that were previously sorted by name alphabetically for Python versions 3.6 and above. Field order will now match that as entered. Rows will be used like tuples and are applied to schema by position. For Python versions < 3.6, the order of kwargs is not guaranteed and therefore will be sorted automatically as in previous versions of Spark.

### Why are the changes needed?

This caused inconsistent behavior in that local Rows could be applied to a schema by matching names, but once serialized the Row could only be used by position and the fields were possibly in a different order.

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

Yes, Row fields are no longer sorted alphabetically but will be in the order entered. For Python < 3.6 `kwargs` can not guarantee the order as entered, so `Row`s will be automatically sorted.

An environment variable "PYSPARK_ROW_FIELD_SORTING_ENABLED" can be set that will override construction of `Row` to maintain compatibility with Spark 2.x.

### How was this patch tested?

Existing tests are run with PYSPARK_ROW_FIELD_SORTING_ENABLED=true and added new test with unsorted fields for Python 3.6+

Closes #26496 from BryanCutler/pyspark-remove-Row-sorting-SPARK-29748.

Authored-by: Bryan Cutler <cutlerb@gmail.com>
Signed-off-by: Bryan Cutler <cutlerb@gmail.com>
2020-01-10 14:37:59 -08:00
HyukjinKwon 92a0877ee1 [SPARK-30464][PYTHON][DOCS] Explicitly note that we don't add "pandas compatible" aliases
### What changes were proposed in this pull request?

This PR adds a note that we're not adding "pandas compatible" aliases anymore.

### Why are the changes needed?

We added "pandas compatible" aliases as of https://github.com/apache/spark/pull/5544 and https://github.com/apache/spark/pull/6066 . There are too many differences and I don't think it makes sense to add such aliases anymore at this moment.

I was even considering deprecating them out but decided to take a more conservative approache by just documenting it.

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

No.

### How was this patch tested?

Existing tests should cover.

Closes #27142 from HyukjinKwon/SPARK-30464.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-01-09 11:42:52 +09:00
HyukjinKwon ee8d661058 [SPARK-30434][PYTHON][SQL] Move pandas related functionalities into 'pandas' sub-package
### What changes were proposed in this pull request?

This PR proposes to move pandas related functionalities into pandas package. Namely:

```bash
pyspark/sql/pandas
├── __init__.py
├── conversion.py  # Conversion between pandas <> PySpark DataFrames
├── functions.py   # pandas_udf
├── group_ops.py   # Grouped UDF / Cogrouped UDF + groupby.apply, groupby.cogroup.apply
├── map_ops.py     # Map Iter UDF + mapInPandas
├── serializers.py # pandas <> PyArrow serializers
├── types.py       # Type utils between pandas <> PyArrow
└── utils.py       # Version requirement checks
```

In order to separately locate `groupby.apply`, `groupby.cogroup.apply`, `mapInPandas`, `toPandas`, and `createDataFrame(pdf)` under `pandas` sub-package, I had to use a mix-in approach which Scala side uses often by `trait`, and also pandas itself uses this approach (see `IndexOpsMixin` as an example) to group related functionalities. Currently, you can think it's like Scala's self typed trait. See the structure below:

```python
class PandasMapOpsMixin(object):
    def mapInPandas(self, ...):
        ...
        return ...

    # other Pandas <> PySpark APIs
```

```python
class DataFrame(PandasMapOpsMixin):

    # other DataFrame APIs equivalent to Scala side.

```

Yes, This is a big PR but they are mostly just moving around except one case `createDataFrame` which I had to split the methods.

### Why are the changes needed?

There are pandas functionalities here and there and I myself gets lost where it was. Also, when you have to make a change commonly for all of pandas related features, it's almost impossible now.

Also, after this change, `DataFrame` and `SparkSession` become more consistent with Scala side since pandas is specific to Python, and this change separates pandas-specific APIs away from `DataFrame` or `SparkSession`.

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

No.

### How was this patch tested?

Existing tests should cover. Also, I manually built the PySpark API documentation and checked.

Closes #27109 from HyukjinKwon/pandas-refactoring.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-01-09 10:22:50 +09:00
HyukjinKwon 866b7df348 [SPARK-30335][SQL][DOCS] Add a note first, last, collect_list and collect_set can be non-deterministic in SQL function docs as well
### What changes were proposed in this pull request?
This PR adds a note first and last can be non-deterministic in SQL function docs as well.
This is already documented in `functions.scala`.

### Why are the changes needed?
Some people look reading SQL docs only.

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

### How was this patch tested?
Jenkins will test.

Closes #27099 from HyukjinKwon/SPARK-30335.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-01-07 14:31:59 +09:00
HyukjinKwon 3ba175ef9a [SPARK-30430][PYTHON][DOCS] Add a note that UserDefinedFunction's constructor is private
### What changes were proposed in this pull request?

This PR adds a note that UserDefinedFunction's constructor is private.

### Why are the changes needed?

To match with Scala side. Scala side does not have it at all.

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

Doc only changes but it declares UserDefinedFunction's constructor is private explicitly.

### How was this patch tested?

Jenkins

Closes #27101 from HyukjinKwon/SPARK-30430.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2020-01-07 10:13:40 +09:00
Gengliang Wang 07593d362f [SPARK-27506][SQL][FOLLOWUP] Use option avroSchema to specify an evolved schema in from_avro
### What changes were proposed in this pull request?

This is a follow-up of https://github.com/apache/spark/pull/26780
In https://github.com/apache/spark/pull/26780, a new Avro data source option `actualSchema` is introduced for setting the original Avro schema in function `from_avro`, while the expected schema is supposed to be set in the parameter `jsonFormatSchema` of `from_avro`.

However, there is another Avro data source option `avroSchema`. It is used for setting the expected schema in readiong and writing.

This PR is to use the option `avroSchema` option for  reading Avro data with an evolved schema and remove the new one `actualSchema`

### Why are the changes needed?

Unify and simplify the Avro data source options.

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

Yes.
To deserialize Avro data with an evolved schema, before changes:
```
from_avro('col, expectedSchema, ("actualSchema" -> actualSchema))
```

After changes:
```
from_avro('col, actualSchema, ("avroSchema" -> expectedSchema))
```

The second parameter is always the actual Avro schema after changes.
### How was this patch tested?

Update the existing tests in https://github.com/apache/spark/pull/26780

Closes #27045 from gengliangwang/renameAvroOption.

Authored-by: Gengliang Wang <gengliang.wang@databricks.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-12-30 18:14:21 +09:00
HyukjinKwon e5abbab0ed [SPARK-30128][DOCS][PYTHON][SQL] Document/promote 'recursiveFileLookup' and 'pathGlobFilter' in file sources 'mergeSchema' in ORC
### What changes were proposed in this pull request?

This PR adds and exposes the options, 'recursiveFileLookup' and 'pathGlobFilter' in file sources 'mergeSchema' in ORC, into documentation.

- `recursiveFileLookup` at file sources: https://github.com/apache/spark/pull/24830 ([SPARK-27627](https://issues.apache.org/jira/browse/SPARK-27627))
- `pathGlobFilter` at file sources: https://github.com/apache/spark/pull/24518 ([SPARK-27990](https://issues.apache.org/jira/browse/SPARK-27990))
- `mergeSchema` at ORC: https://github.com/apache/spark/pull/24043 ([SPARK-11412](https://issues.apache.org/jira/browse/SPARK-11412))

**Note that** `timeZone` option was not moved from `DataFrameReader.options` as I assume it will likely affect other datasources as well once DSv2 is complete.

### Why are the changes needed?

To document available options in sources properly.

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

In PySpark, `pathGlobFilter` can be set via `DataFrameReader.(text|orc|parquet|json|csv)` and `DataStreamReader.(text|orc|parquet|json|csv)`.

### How was this patch tested?

Manually built the doc and checked the output. Option setting in PySpark is rather a logical change. I manually tested one only:

```bash
$ ls -al tmp
...
-rw-r--r--   1 hyukjin.kwon  staff     3 Dec 20 12:19 aa
-rw-r--r--   1 hyukjin.kwon  staff     3 Dec 20 12:19 ab
-rw-r--r--   1 hyukjin.kwon  staff     3 Dec 20 12:19 ac
-rw-r--r--   1 hyukjin.kwon  staff     3 Dec 20 12:19 cc
```

```python
>>> spark.read.text("tmp", pathGlobFilter="*c").show()
```

```
+-----+
|value|
+-----+
|   ac|
|   cc|
+-----+
```

Closes #26958 from HyukjinKwon/doc-followup.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-12-23 09:57:42 +09:00
Boris Boutkov 3bf5498b4a [MINOR][DOCS] Fix documentation for slide function
### What changes were proposed in this pull request?

This PR proposes to fix documentation for slide function. Fixed the spacing issue and added some parameter related info.

### Why are the changes needed?

Documentation improvement

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

No (doc-only change).

### How was this patch tested?

Manually tested by documentation build.

Closes #26896 from bboutkov/pyspark_doc_fix.

Authored-by: Boris Boutkov <boris.boutkov@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-12-16 16:29:09 +09:00
HyukjinKwon 0a2afcec7d [SPARK-30200][SQL][FOLLOW-UP] Expose only explain(mode: String) in Scala side, and clean up related codes
### What changes were proposed in this pull request?

This PR mainly targets:

1. Expose only explain(mode: String) in Scala side
2. Clean up related codes
    - Hide `ExplainMode` under private `execution` package. No particular reason but just because `ExplainUtils` exists there
    - Use `case object` + `trait` pattern in `ExplainMode` to look after `ParseMode`.
    -  Move `Dataset.toExplainString` to `QueryExecution.explainString` to look after `QueryExecution.simpleString`, and deduplicate the codes at `ExplainCommand`.
    - Use `ExplainMode` in `ExplainCommand` too.
    - Add `explainString` to `PythonSQLUtils` to avoid unexpected test failure of PySpark during refactoring Scala codes side.

### Why are the changes needed?

To minimised exposed APIs, deduplicate, and clean up.

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

`Dataset.explain(mode: ExplainMode)` will be removed (which only exists in master).

### How was this patch tested?

Manually tested and existing tests should cover.

Closes #26898 from HyukjinKwon/SPARK-30200-followup.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-12-16 14:42:35 +09:00
Takeshi Yamamuro f483a13d4a [SPARK-30231][SQL][PYTHON][FOLLOWUP] Make error messages clear in PySpark df.explain
### What changes were proposed in this pull request?

This pr is a followup of #26861 to address minor comments from viirya.

### Why are the changes needed?

For better error messages.

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

No.

### How was this patch tested?

Manually tested.

Closes #26886 from maropu/SPARK-30231-FOLLOWUP.

Authored-by: Takeshi Yamamuro <yamamuro@apache.org>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2019-12-14 14:26:50 -08:00
Takeshi Yamamuro 64c7b94d64 [SPARK-30231][SQL][PYTHON] Support explain mode in PySpark df.explain
### What changes were proposed in this pull request?

This pr intends to support explain modes implemented in #26829 for PySpark.

### Why are the changes needed?

For better debugging info. in PySpark dataframes.

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

No.

### How was this patch tested?

Added UTs.

Closes #26861 from maropu/ExplainModeInPython.

Authored-by: Takeshi Yamamuro <yamamuro@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-12-13 17:44:23 +09:00
David 8e9bfea107 [SPARK-29188][PYTHON] toPandas (without Arrow) gets wrong dtypes when applied on empty DF
### What changes were proposed in this pull request?

An empty Spark DataFrame converted to a Pandas DataFrame wouldn't have the right column types. Several type mappings were missing.

### Why are the changes needed?

Empty Spark DataFrames can be used to write unit tests, and verified by converting them to Pandas first. But this can fail when the column types are wrong.

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

Yes; the error reported in the JIRA issue should not happen anymore.

### How was this patch tested?

Through unit tests in `pyspark.sql.tests.test_dataframe.DataFrameTests#test_to_pandas_from_empty_dataframe`

Closes #26747 from dlindelof/SPARK-29188.

Authored-by: David <dlindelof@expediagroup.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-12-12 20:49:10 +09:00
Fokko Driesprong 99ea324b6f [SPARK-27506][SQL] Allow deserialization of Avro data using compatible schemas
Follow up of https://github.com/apache/spark/pull/24405

### What changes were proposed in this pull request?
The current implementation of _from_avro_ and _AvroDataToCatalyst_ doesn't allow doing schema evolution since it requires the deserialization of an Avro record with the exact same schema with which it was serialized.

The proposed change is to add a new option `actualSchema` to allow passing the schema used to serialize the records. This allows using a different compatible schema for reading by passing both schemas to _GenericDatumReader_. If no writer's schema is provided, nothing changes from before.

### Why are the changes needed?
Consider the following example.

```
// schema ID: 1
val schema1 = """
{
    "type": "record",
    "name": "MySchema",
    "fields": [
        {"name": "col1", "type": "int"},
        {"name": "col2", "type": "string"}
     ]
}
"""

// schema ID: 2
val schema2 = """
{
    "type": "record",
    "name": "MySchema",
    "fields": [
        {"name": "col1", "type": "int"},
        {"name": "col2", "type": "string"},
        {"name": "col3", "type": "string", "default": ""}
     ]
}
"""
```

The two schemas are compatible - i.e. you can use `schema2` to deserialize events serialized with `schema1`, in which case there will be the field `col3` with the default value.

Now imagine that you have two dataframes (read from batch or streaming), one with Avro events from schema1 and the other with events from schema2. **We want to combine them into one dataframe** for storing or further processing.

With the current `from_avro` function we can only decode each of them with the corresponding schema:

```
scalaval df1 = ... // Avro events created with schema1
df1: org.apache.spark.sql.DataFrame = [eventBytes: binary]
scalaval decodedDf1 = df1.select(from_avro('eventBytes, schema1) as "decoded")
decodedDf1: org.apache.spark.sql.DataFrame = [decoded: struct<col1: int, col2: string>]

scalaval df2= ... // Avro events created with schema2
df2: org.apache.spark.sql.DataFrame = [eventBytes: binary]
scalaval decodedDf2 = df2.select(from_avro('eventBytes, schema2) as "decoded")
decodedDf2: org.apache.spark.sql.DataFrame = [decoded: struct<col1: int, col2: string, col3: string>]
```

but then `decodedDf1` and `decodedDf2` have different Spark schemas and we can't union them. Instead, with the proposed change we can decode `df1` in the following way:

```
scalaimport scala.collection.JavaConverters._
scalaval decodedDf1 = df1.select(from_avro(data = 'eventBytes, jsonFormatSchema = schema2, options = Map("actualSchema" -> schema1).asJava) as "decoded")
decodedDf1: org.apache.spark.sql.DataFrame = [decoded: struct<col1: int, col2: string, col3: string>]
```

so that both dataframes have the same schemas and can be merged.

### Does this PR introduce any user-facing change?
This PR allows users to pass a new configuration but it doesn't affect current code.

### How was this patch tested?
A new unit test was added.

Closes #26780 from Fokko/SPARK-27506.

Lead-authored-by: Fokko Driesprong <fokko@apache.org>
Co-authored-by: Gianluca Amori <gianluca.amori@gmail.com>
Signed-off-by: Gengliang Wang <gengliang.wang@databricks.com>
2019-12-11 01:26:29 -08:00
Nicholas Chammas c8922d9145 [SPARK-30113][SQL][PYTHON] Expose mergeSchema option in PySpark's ORC APIs
### What changes were proposed in this pull request?

This PR is a follow-up to #24043 and cousin of #26730. It exposes the `mergeSchema` option directly in the ORC APIs.

### Why are the changes needed?

So the Python API matches the Scala API.

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

Yes, it adds a new option directly in the ORC reader method signatures.

### How was this patch tested?

I tested this manually as follows:

```
>>> spark.range(3).write.orc('test-orc')
>>> spark.range(3).withColumnRenamed('id', 'name').write.orc('test-orc/nested')
>>> spark.read.orc('test-orc', recursiveFileLookup=True, mergeSchema=True)
DataFrame[id: bigint, name: bigint]
>>> spark.read.orc('test-orc', recursiveFileLookup=True, mergeSchema=False)
DataFrame[id: bigint]
>>> spark.conf.set('spark.sql.orc.mergeSchema', True)
>>> spark.read.orc('test-orc', recursiveFileLookup=True)
DataFrame[id: bigint, name: bigint]
>>> spark.read.orc('test-orc', recursiveFileLookup=True, mergeSchema=False)
DataFrame[id: bigint]
```

Closes #26755 from nchammas/SPARK-30113-ORC-mergeSchema.

Authored-by: Nicholas Chammas <nicholas.chammas@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-12-04 11:44:24 +09:00
Nicholas Chammas e766a323bc [SPARK-30091][SQL][PYTHON] Document mergeSchema option directly in the PySpark Parquet APIs
### What changes were proposed in this pull request?

This change properly documents the `mergeSchema` option directly in the Python APIs for reading Parquet data.

### Why are the changes needed?

The docstring for `DataFrameReader.parquet()` mentions `mergeSchema` but doesn't show it in the API. It seems like a simple oversight.

Before this PR, you'd have to do this to use `mergeSchema`:

```python
spark.read.option('mergeSchema', True).parquet('test-parquet').show()
```

After this PR, you can use the option as (I believe) it was intended to be used:

```python
spark.read.parquet('test-parquet', mergeSchema=True).show()
```

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

Yes, this PR changes the signatures of `DataFrameReader.parquet()` and `DataStreamReader.parquet()` to match their docstrings.

### How was this patch tested?

Testing the `mergeSchema` option directly seems to be left to the Scala side of the codebase. I tested my change manually to confirm the API works.

I also confirmed that setting `spark.sql.parquet.mergeSchema` at the session does not get overridden by leaving `mergeSchema` at its default when calling `parquet()`:

```
>>> spark.conf.set('spark.sql.parquet.mergeSchema', True)
>>> spark.range(3).write.parquet('test-parquet/id')
>>> spark.range(3).withColumnRenamed('id', 'name').write.parquet('test-parquet/name')
>>> spark.read.option('recursiveFileLookup', True).parquet('test-parquet').show()
+----+----+
|  id|name|
+----+----+
|null|   1|
|null|   2|
|null|   0|
|   1|null|
|   2|null|
|   0|null|
+----+----+
>>> spark.read.option('recursiveFileLookup', True).parquet('test-parquet', mergeSchema=False).show()
+----+
|  id|
+----+
|null|
|null|
|null|
|   1|
|   2|
|   0|
+----+
```

Closes #26730 from nchammas/parquet-merge-schema.

Authored-by: Nicholas Chammas <nicholas.chammas@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-12-04 11:31:57 +09:00
Nicholas Chammas 3dd3a623f2 [SPARK-27990][SPARK-29903][PYTHON] Add recursiveFileLookup option to Python DataFrameReader
### What changes were proposed in this pull request?

As a follow-up to #24830, this PR adds the `recursiveFileLookup` option to the Python DataFrameReader API.

### Why are the changes needed?

This PR maintains Python feature parity with Scala.

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

Yes.

Before this PR, you'd only be able to use this option as follows:

```python
spark.read.option("recursiveFileLookup", True).text("test-data").show()
```

With this PR, you can reference the option from within the format-specific method:

```python
spark.read.text("test-data", recursiveFileLookup=True).show()
```

This option now also shows up in the Python API docs.

### How was this patch tested?

I tested this manually by creating the following directories with dummy data:

```
test-data
├── 1.txt
└── nested
   └── 2.txt
test-parquet
├── nested
│  ├── _SUCCESS
│  ├── part-00000-...-.parquet
├── _SUCCESS
├── part-00000-...-.parquet
```

I then ran the following tests and confirmed the output looked good:

```python
spark.read.parquet("test-parquet", recursiveFileLookup=True).show()
spark.read.text("test-data", recursiveFileLookup=True).show()
spark.read.csv("test-data", recursiveFileLookup=True).show()
```

`python/pyspark/sql/tests/test_readwriter.py` seems pretty sparse. I'm happy to add my tests there, though it seems we have been deferring testing like this to the Scala side of things.

Closes #26718 from nchammas/SPARK-27990-recursiveFileLookup-python.

Authored-by: Nicholas Chammas <nicholas.chammas@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-12-04 10:10:30 +09:00
Bryan Cutler 65a189c7a1 [SPARK-29376][SQL][PYTHON] Upgrade Apache Arrow to version 0.15.1
### What changes were proposed in this pull request?

Upgrade Apache Arrow to version 0.15.1. This includes Java artifacts and increases the minimum required version of PyArrow also.

Version 0.12.0 to 0.15.1 includes the following selected fixes/improvements relevant to Spark users:

* ARROW-6898 - [Java] Fix potential memory leak in ArrowWriter and several test classes
* ARROW-6874 - [Python] Memory leak in Table.to_pandas() when conversion to object dtype
* ARROW-5579 - [Java] shade flatbuffer dependency
* ARROW-5843 - [Java] Improve the readability and performance of BitVectorHelper#getNullCount
* ARROW-5881 - [Java] Provide functionalities to efficiently determine if a validity buffer has completely 1 bits/0 bits
* ARROW-5893 - [C++] Remove arrow::Column class from C++ library
* ARROW-5970 - [Java] Provide pointer to Arrow buffer
* ARROW-6070 - [Java] Avoid creating new schema before IPC sending
* ARROW-6279 - [Python] Add Table.slice method or allow slices in \_\_getitem\_\_
* ARROW-6313 - [Format] Tracking for ensuring flatbuffer serialized values are aligned in stream/files.
* ARROW-6557 - [Python] Always return pandas.Series from Array/ChunkedArray.to_pandas, propagate field names to Series from RecordBatch, Table
* ARROW-2015 - [Java] Use Java Time and Date APIs instead of JodaTime
* ARROW-1261 - [Java] Add container type for Map logical type
* ARROW-1207 - [C++] Implement Map logical type

Changelog can be seen at https://arrow.apache.org/release/0.15.0.html

### Why are the changes needed?

Upgrade to get bug fixes, improvements, and maintain compatibility with future versions of PyArrow.

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

No

### How was this patch tested?

Existing tests, manually tested with Python 3.7, 3.8

Closes #26133 from BryanCutler/arrow-upgrade-015-SPARK-29376.

Authored-by: Bryan Cutler <cutlerb@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-11-15 13:27:30 +09:00
Bago Amirbekian 8152a87235 [SPARK-28978][ ] Support > 256 args to python udf
### What changes were proposed in this pull request?

On the worker we express lambda functions as strings and then eval them to create a "mapper" function. This make the code hard to read & limits the # of arguments a udf can support to 256 for python <= 3.6.

This PR rewrites the mapper functions as nested functions instead of "lambda strings" and allows passing in more than 255 args.

### Why are the changes needed?
The jira ticket associated with this issue describes how MLflow uses udfs to consume columns as features. This pattern isn't unique and a limit of 255 features is quite low.

### Does this PR introduce any user-facing change?
Users can now pass more than 255 cols to a udf function.

### How was this patch tested?
Added a unit test for passing in > 255 args to udf.

Closes #26442 from MrBago/replace-lambdas-on-worker.

Authored-by: Bago Amirbekian <bago@databricks.com>
Signed-off-by: Xiangrui Meng <meng@databricks.com>
2019-11-08 19:19:14 -08:00
HyukjinKwon 7fc9db0853 [SPARK-29798][PYTHON][SQL] Infers bytes as binary type in createDataFrame in Python 3 at PySpark
### What changes were proposed in this pull request?

This PR proposes to infer bytes as binary types in Python 3. See https://github.com/apache/spark/pull/25749 for discussions. I have also checked that Arrow considers `bytes` as binary type, and PySpark UDF can also accepts `bytes` as a binary type.

Since `bytes` is not a `str` anymore in Python 3, it's clear to call it `BinaryType` in Python 3.

### Why are the changes needed?

To respect Python 3's `bytes` type and support Python's primitive types.

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

Yes.

**Before:**

```python
>>> spark.createDataFrame([[b"abc"]])
Traceback (most recent call last):
  File "/.../spark/python/pyspark/sql/types.py", line 1036, in _infer_type
    return _infer_schema(obj)
  File "/.../spark/python/pyspark/sql/types.py", line 1062, in _infer_schema
    raise TypeError("Can not infer schema for type: %s" % type(row))
TypeError: Can not infer schema for type: <class 'bytes'>

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/.../spark/python/pyspark/sql/session.py", line 787, in createDataFrame
    rdd, schema = self._createFromLocal(map(prepare, data), schema)
  File "/.../spark/python/pyspark/sql/session.py", line 445, in _createFromLocal
    struct = self._inferSchemaFromList(data, names=schema)
  File "/.../spark/python/pyspark/sql/session.py", line 377, in _inferSchemaFromList
    schema = reduce(_merge_type, (_infer_schema(row, names) for row in data))
  File "/.../spark/python/pyspark/sql/session.py", line 377, in <genexpr>
    schema = reduce(_merge_type, (_infer_schema(row, names) for row in data))
  File "/.../spark/python/pyspark/sql/types.py", line 1064, in _infer_schema
    fields = [StructField(k, _infer_type(v), True) for k, v in items]
  File "/.../spark/python/pyspark/sql/types.py", line 1064, in <listcomp>
    fields = [StructField(k, _infer_type(v), True) for k, v in items]
  File "/.../spark/python/pyspark/sql/types.py", line 1038, in _infer_type
    raise TypeError("not supported type: %s" % type(obj))
TypeError: not supported type: <class 'bytes'>
```

**After:**

```python
>>> spark.createDataFrame([[b"abc"]])
DataFrame[_1: binary]
```

### How was this patch tested?
Unittest was added and manually tested.

Closes #26432 from HyukjinKwon/SPARK-29798.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: Bryan Cutler <cutlerb@gmail.com>
2019-11-08 12:10:39 -08:00
Matt Stillwell 1e1b7302f4 [MINOR][PYSPARK][DOCS] Fix typo in example documentation
### What changes were proposed in this pull request?

I propose that we change the example code documentation to call the proper function .
For example, under the `foreachBatch` function, the example code was calling the `foreach()` function by mistake.

### Why are the changes needed?

I suppose it could confuse some people, and it is a typo

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

No, there is no "meaningful" code being change, simply the documentation

### How was this patch tested?

I made the change on a fork and it still worked

Closes #26299 from mstill3/patch-1.

Authored-by: Matt Stillwell <18670089+mstill3@users.noreply.github.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2019-11-01 11:55:29 -07:00
Terry Kim 3175f4bf1b [SPARK-29664][PYTHON][SQL] Column.getItem behavior is not consistent with Scala
### What changes were proposed in this pull request?

This PR changes the behavior of `Column.getItem` to call `Column.getItem` on Scala side instead of `Column.apply`.

### Why are the changes needed?

The current behavior is not consistent with that of Scala.

In PySpark:
```Python
df = spark.range(2)
map_col = create_map(lit(0), lit(100), lit(1), lit(200))
df.withColumn("mapped", map_col.getItem(col('id'))).show()
# +---+------+
# | id|mapped|
# +---+------+
# |  0|   100|
# |  1|   200|
# +---+------+
```
In Scala:
```Scala
val df = spark.range(2)
val map_col = map(lit(0), lit(100), lit(1), lit(200))
// The following getItem results in the following exception, which is the right behavior:
// java.lang.RuntimeException: Unsupported literal type class org.apache.spark.sql.Column id
//  at org.apache.spark.sql.catalyst.expressions.Literal$.apply(literals.scala:78)
//  at org.apache.spark.sql.Column.getItem(Column.scala:856)
//  ... 49 elided
df.withColumn("mapped", map_col.getItem(col("id"))).show
```

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

Yes. If the use wants to pass `Column` object to `getItem`, he/she now needs to use the indexing operator to achieve the previous behavior.

```Python
df = spark.range(2)
map_col = create_map(lit(0), lit(100), lit(1), lit(200))
df.withColumn("mapped", map_col[col('id'))].show()
# +---+------+
# | id|mapped|
# +---+------+
# |  0|   100|
# |  1|   200|
# +---+------+
```

### How was this patch tested?

Existing tests.

Closes #26351 from imback82/spark-29664.

Authored-by: Terry Kim <yuminkim@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-11-01 12:25:48 +09:00
Chris Martin c29494377b [SPARK-29126][PYSPARK][DOC] Pandas Cogroup udf usage guide
This PR adds some extra documentation for the new Cogrouped map Pandas udfs.  Specifically:

- Updated the usage guide for the new `COGROUPED_MAP` Pandas udfs added in https://github.com/apache/spark/pull/24981
- Updated the docstring for pandas_udf to include the COGROUPED_MAP type as suggested by HyukjinKwon in https://github.com/apache/spark/pull/25939

Closes #26110 from d80tb7/SPARK-29126-cogroup-udf-usage-guide.

Authored-by: Chris Martin <chris@cmartinit.co.uk>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-10-31 10:41:57 +09:00
HyukjinKwon 8682bb11ae [SPARK-29627][PYTHON][SQL] Allow array_contains to take column instances
### What changes were proposed in this pull request?

This PR proposes to allow `array_contains` to take column instances.

### Why are the changes needed?

For consistent support in Scala and Python APIs. Scala allows column instances at `array_contains`

Scala:

```scala
import org.apache.spark.sql.functions._
val df = Seq(Array("a", "b", "c"), Array.empty[String]).toDF("data")
df.select(array_contains($"data", lit("a"))).show()
```

Python:

```python
from pyspark.sql.functions import array_contains, lit
df = spark.createDataFrame([(["a", "b", "c"],), ([],)], ['data'])
df.select(array_contains(df.data, lit("a"))).show()
```

However, PySpark sides does not allow.

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

Yes.

```python
from pyspark.sql.functions import array_contains, lit
df = spark.createDataFrame([(["a", "b", "c"],), ([],)], ['data'])
df.select(array_contains(df.data, lit("a"))).show()
```

**Before:**

```
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/.../spark/python/pyspark/sql/functions.py", line 1950, in array_contains
    return Column(sc._jvm.functions.array_contains(_to_java_column(col), value))
  File "/.../spark/python/lib/py4j-0.10.8.1-src.zip/py4j/java_gateway.py", line 1277, in __call__
  File "/.../spark/python/lib/py4j-0.10.8.1-src.zip/py4j/java_gateway.py", line 1241, in _build_args
  File "/.../spark/python/lib/py4j-0.10.8.1-src.zip/py4j/java_gateway.py", line 1228, in _get_args
  File "/.../spark/python/lib/py4j-0.10.8.1-src.zip/py4j/java_collections.py", line 500, in convert
  File "/.../spark/python/pyspark/sql/column.py", line 344, in __iter__
    raise TypeError("Column is not iterable")
TypeError: Column is not iterable
```

**After:**

```
+-----------------------+
|array_contains(data, a)|
+-----------------------+
|                   true|
|                  false|
+-----------------------+
```

### How was this patch tested?

Manually tested and added a doctest.

Closes #26288 from HyukjinKwon/SPARK-29627.

Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-10-30 09:45:19 +09:00
stczwd dcf5eaf1a6 [SPARK-29444][FOLLOWUP] add doc and python parameter for ignoreNullFields in json generating
# What changes were proposed in this pull request?
Add description for ignoreNullFields, which is commited in #26098 , in DataFrameWriter and readwriter.py.
Enable user to use ignoreNullFields in pyspark.

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

### How was this patch tested?
run unit tests

Closes #26227 from stczwd/json-generator-doc.

Authored-by: stczwd <qcsd2011@163.com>
Signed-off-by: Dongjoon Hyun <dhyun@apple.com>
2019-10-24 10:25:04 -07:00
Jeff Evans 95de93b24e [SPARK-24540][SQL] Support for multiple character delimiter in Spark CSV read
Updating univocity-parsers version to 2.8.3, which adds support for multiple character delimiters

Moving univocity-parsers version to spark-parent pom dependencyManagement section

Adding new utility method to build multi-char delimiter string, which delegates to existing one

Adding tests for multiple character delimited CSV

### What changes were proposed in this pull request?

Adds support for parsing CSV data using multiple-character delimiters.  Existing logic for converting the input delimiter string to characters was kept and invoked in a loop.  Project dependencies were updated to remove redundant declaration of `univocity-parsers` version, and also to change that version to the latest.

### Why are the changes needed?

It is quite common for people to have delimited data, where the delimiter is not a single character, but rather a sequence of characters.  Currently, it is difficult to handle such data in Spark (typically needs pre-processing).

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

Yes. Specifying the "delimiter" option for the DataFrame read, and providing more than one character, will no longer result in an exception.  Instead, it will be converted as before and passed to the underlying library (Univocity), which has accepted multiple character delimiters since 2.8.0.

### How was this patch tested?

The `CSVSuite` tests were confirmed passing (including new methods), and `sbt` tests for `sql` were executed.

Closes #26027 from jeff303/SPARK-24540.

Authored-by: Jeff Evans <jeffrey.wayne.evans@gmail.com>
Signed-off-by: Sean Owen <sean.owen@databricks.com>
2019-10-15 15:44:51 -05:00
Bryan Cutler beb8d2f8ad [SPARK-29402][PYTHON][TESTS] Added tests for grouped map pandas_udf with window
### What changes were proposed in this pull request?

Added tests for grouped map pandas_udf using a window.

### Why are the changes needed?

Current tests for grouped map do not use a window and this had previously caused an error due the window range being a struct column, which was not yet supported.

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

No

### How was this patch tested?

New tests added.

Closes #26063 from BryanCutler/pyspark-pandas_udf-group-with-window-tests-SPARK-29402.

Authored-by: Bryan Cutler <cutlerb@gmail.com>
Signed-off-by: Bryan Cutler <cutlerb@gmail.com>
2019-10-11 16:19:13 -07:00
Chris Martin 76791b89f5 [SPARK-27463][PYTHON][FOLLOW-UP] Miscellaneous documentation and code cleanup of cogroup pandas UDF
Follow up from https://github.com/apache/spark/pull/24981 incorporating some comments from HyukjinKwon.

Specifically:

- Adding `CoGroupedData` to `pyspark/sql/__init__.py __all__` so that documentation is generated.
- Added pydoc, including example, for the use case whereby the user supplies a cogrouping function including a key.
- Added the boilerplate for doctests to cogroup.py.  Note that cogroup.py only contains the apply() function which has doctests disabled as per the  other Pandas Udfs.
- Restricted the newly exposed RelationalGroupedDataset constructor parameters to access only by the sql package.
- Some minor  formatting tweaks.

This was tested by running the appropriate unit tests.  I'm unsure as to how to check that my change will cause the documentation to be generated correctly, but it someone can describe how I can do this I'd be happy to check.

Closes #25939 from d80tb7/SPARK-27463-fixes.

Authored-by: Chris Martin <chris@cmartinit.co.uk>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
2019-09-30 22:25:35 +09:00