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## What changes were proposed in this pull request? This change is a cleanup and consolidation of 3 areas related to Pandas UDFs: 1) `ArrowStreamPandasSerializer` now inherits from `ArrowStreamSerializer` and uses the base class `dump_stream`, `load_stream` to create Arrow reader/writer and send Arrow record batches. `ArrowStreamPandasSerializer` makes the conversions to/from Pandas and converts to Arrow record batch iterators. This change removed duplicated creation of Arrow readers/writers. 2) `createDataFrame` with Arrow now uses `ArrowStreamPandasSerializer` instead of doing its own conversions from Pandas to Arrow and sending record batches through `ArrowStreamSerializer`. 3) Grouped Map UDFs now reuse existing logic in `ArrowStreamPandasSerializer` to send Pandas DataFrame results as a `StructType` instead of separating each column from the DataFrame. This makes the code a little more consistent with the Python worker, but does require that the returned StructType column is flattened out in `FlatMapGroupsInPandasExec` in Scala. ## How was this patch tested? Existing tests and ran tests with pyarrow 0.12.0 Closes #24095 from BryanCutler/arrow-refactor-cleanup-UDFs. Authored-by: Bryan Cutler <cutlerb@gmail.com> Signed-off-by: Hyukjin Kwon <gurwls223@apache.org> |
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| README.md | ||
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| setup.py | ||
Apache Spark
Spark is a fast and general cluster computing system for Big Data. It provides high-level APIs in Scala, Java, Python, and R, and an optimized engine that supports general computation graphs for data analysis. It also supports a rich set of higher-level tools including Spark SQL for SQL and DataFrames, MLlib for machine learning, GraphX for graph processing, and Spark Streaming for stream processing.
Online Documentation
You can find the latest Spark documentation, including a programming guide, on the project web page
Python Packaging
This README file only contains basic information related to pip installed PySpark. This packaging is currently experimental and may change in future versions (although we will do our best to keep compatibility). Using PySpark requires the Spark JARs, and if you are building this from source please see the builder instructions at "Building Spark".
The Python packaging for Spark is not intended to replace all of the other use cases. This Python packaged version of Spark is suitable for interacting with an existing cluster (be it Spark standalone, YARN, or Mesos) - but does not contain the tools required to set up your own standalone Spark cluster. You can download the full version of Spark from the Apache Spark downloads page.
NOTE: If you are using this with a Spark standalone cluster you must ensure that the version (including minor version) matches or you may experience odd errors.
Python Requirements
At its core PySpark depends on Py4J (currently version 0.10.8.1), but some additional sub-packages have their own extra requirements for some features (including numpy, pandas, and pyarrow).