### What changes were proposed in this pull request?
Upgrade Apache Arrow to version 1.0.1 for the Java dependency and increase minimum version of PyArrow to 1.0.0.
This release marks a transition to binary stability of the columnar format (which was already informally backward-compatible going back to December 2017) and a transition to Semantic Versioning for the Arrow software libraries. Also note that the Java arrow-memory artifact has been split to separate dependence on netty-buffer and allow users to select an allocator. Spark will continue to use `arrow-memory-netty` to maintain performance benefits.
Version 1.0.0 - 1.0.0 include the following selected fixes/improvements relevant to Spark users:
ARROW-9300 - [Java] Separate Netty Memory to its own module
ARROW-9272 - [C++][Python] Reduce complexity in python to arrow conversion
ARROW-9016 - [Java] Remove direct references to Netty/Unsafe Allocators
ARROW-8664 - [Java] Add skip null check to all Vector types
ARROW-8485 - [Integration][Java] Implement extension types integration
ARROW-8434 - [C++] Ipc RecordBatchFileReader deserializes the Schema multiple times
ARROW-8314 - [Python] Provide a method to select a subset of columns of a Table
ARROW-8230 - [Java] Move Netty memory manager into a separate module
ARROW-8229 - [Java] Move ArrowBuf into the Arrow package
ARROW-7955 - [Java] Support large buffer for file/stream IPC
ARROW-7831 - [Java] unnecessary buffer allocation when calling splitAndTransferTo on variable width vectors
ARROW-6111 - [Java] Support LargeVarChar and LargeBinary types and add integration test with C++
ARROW-6110 - [Java] Support LargeList Type and add integration test with C++
ARROW-5760 - [C++] Optimize Take implementation
ARROW-300 - [Format] Add body buffer compression option to IPC message protocol using LZ4 or ZSTD
ARROW-9098 - RecordBatch::ToStructArray cannot handle record batches with 0 column
ARROW-9066 - [Python] Raise correct error in isnull()
ARROW-9223 - [Python] Fix to_pandas() export for timestamps within structs
ARROW-9195 - [Java] Wrong usage of Unsafe.get from bytearray in ByteFunctionsHelper class
ARROW-7610 - [Java] Finish support for 64 bit int allocations
ARROW-8115 - [Python] Conversion when mixing NaT and datetime objects not working
ARROW-8392 - [Java] Fix overflow related corner cases for vector value comparison
ARROW-8537 - [C++] Performance regression from ARROW-8523
ARROW-8803 - [Java] Row count should be set before loading buffers in VectorLoader
ARROW-8911 - [C++] Slicing a ChunkedArray with zero chunks segfaults
View release notes here:
https://arrow.apache.org/release/1.0.1.htmlhttps://arrow.apache.org/release/1.0.0.html
### Why are the changes needed?
Upgrade brings fixes, improvements and stability guarantees.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
Existing tests with pyarrow 1.0.0 and 1.0.1
Closes#29686 from BryanCutler/arrow-upgrade-100-SPARK-32312.
Authored-by: Bryan Cutler <cutlerb@gmail.com>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
### 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>
Bryan Cutler
HyukjinKwon