feeca63198
### What changes were proposed in this pull request?
This PR proposes to remove the warning about multi-thread in local properties, and change the guide to use `collectWithJobGroup` for multi-threads for now because:
- It is too noisy to users who don't use multiple threads - the number of this single thread case is arguably more prevailing.
- There was a critical issue found about pin-thread mode SPARK-32010, which will be fixed in Spark 3.1.
- To smoothly migrate, `RDD.collectWithJobGroup` was added, which will be deprecated in Spark 3.1 with SPARK-32010 fixed.
I will target to deprecate `RDD.collectWithJobGroup`, and make this pin-thread mode stable in Spark 3.1. In the future releases, I plan to make this mode as a default mode, and remove `RDD.collectWithJobGroup` away.
### Why are the changes needed?
To avoid guiding users a feature with a critical issue, and provide a proper workaround for now.
### Does this PR introduce _any_ user-facing change?
Yes, warning message and documentation.
### How was this patch tested?
Manually tested:
Before:
```
>>> spark.sparkContext.setLocalProperty("a", "b")
/.../spark/python/pyspark/util.py:141: UserWarning: Currently, 'setLocalProperty' (set to local
properties) with multiple threads does not properly work.
Internally threads on PVM and JVM are not synced, and JVM thread can be reused for multiple
threads on PVM, which fails to isolate local properties for each thread on PVM.
To work around this, you can set PYSPARK_PIN_THREAD to true (see SPARK-22340). However,
note that it cannot inherit the local properties from the parent thread although it isolates each
thread on PVM and JVM with its own local properties.
To work around this, you should manually copy and set the local properties from the parent thread
to the child thread when you create another thread.
```
After:
```
>>> spark.sparkContext.setLocalProperty("a", "b")
```
Closes #28845 from HyukjinKwon/SPARK-32011.
Authored-by: HyukjinKwon <gurwls223@apache.org>
Signed-off-by: HyukjinKwon <gurwls223@apache.org>
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| .. | ||
| docs | ||
| lib | ||
| pyspark | ||
| test_coverage | ||
| test_support | ||
| .coveragerc | ||
| .gitignore | ||
| MANIFEST.in | ||
| pylintrc | ||
| README.md | ||
| run-tests | ||
| run-tests-with-coverage | ||
| run-tests.py | ||
| setup.cfg | ||
| setup.py | ||
Apache Spark
Spark is a unified analytics engine for large-scale data processing. It provides high-level APIs in Scala, Java, Python, and R, and an optimized engine that supports general computation graphs for data analysis. It also supports a rich set of higher-level tools including Spark SQL for SQL and DataFrames, MLlib for machine learning, GraphX for graph processing, and Structured Streaming for stream processing.
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, but some additional sub-packages have their own extra requirements for some features (including numpy, pandas, and pyarrow).