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### What changes were proposed in this pull request? Add a new logical node AggregateWithHaving, and the parser should create this plan for HAVING. The analyzer resolves it to Filter(..., Aggregate(...)). ### Why are the changes needed? The SQL parser in Spark creates Filter(..., Aggregate(...)) for the HAVING query, and Spark has a special analyzer rule ResolveAggregateFunctions to resolve the aggregate functions and grouping columns in the Filter operator. It works for simple cases in a very tricky way as it relies on rule execution order: 1. Rule ResolveReferences hits the Aggregate operator and resolves attributes inside aggregate functions, but the function itself is still unresolved as it's an UnresolvedFunction. This stops resolving the Filter operator as the child Aggrege operator is still unresolved. 2. Rule ResolveFunctions resolves UnresolvedFunction. This makes the Aggrege operator resolved. 3. Rule ResolveAggregateFunctions resolves the Filter operator if its child is a resolved Aggregate. This rule can correctly resolve the grouping columns. In the example query, I put a CAST, which needs to be resolved by rule ResolveTimeZone, which runs after ResolveAggregateFunctions. This breaks step 3 as the Aggregate operator is unresolved at that time. Then the analyzer starts next round and the Filter operator is resolved by ResolveReferences, which wrongly resolves the grouping columns. See the demo below: ``` SELECT SUM(a) AS b, '2020-01-01' AS fake FROM VALUES (1, 10), (2, 20) AS T(a, b) GROUP BY b HAVING b > 10 ``` The query's result is ``` +---+----------+ | b| fake| +---+----------+ | 2|2020-01-01| +---+----------+ ``` But if we add CAST, it will return an empty result. ``` SELECT SUM(a) AS b, CAST('2020-01-01' AS DATE) AS fake FROM VALUES (1, 10), (2, 20) AS T(a, b) GROUP BY b HAVING b > 10 ``` ### Does this PR introduce any user-facing change? Yes, bug fix for cast in having aggregate expressions. ### How was this patch tested? New UT added. Closes #28294 from xuanyuanking/SPARK-31519. Authored-by: Yuanjian Li <xyliyuanjian@gmail.com> Signed-off-by: Wenchen Fan <wenchen@databricks.com> |
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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. This README file only contains basic setup instructions.
Building Spark
Spark is built using Apache Maven. To build Spark and its example programs, run:
./build/mvn -DskipTests clean package
(You do not need to do this if you downloaded a pre-built package.)
More detailed documentation is available from the project site, at "Building Spark".
For general development tips, including info on developing Spark using an IDE, see "Useful Developer Tools".
Interactive Scala Shell
The easiest way to start using Spark is through the Scala shell:
./bin/spark-shell
Try the following command, which should return 1,000,000,000:
scala> spark.range(1000 * 1000 * 1000).count()
Interactive Python Shell
Alternatively, if you prefer Python, you can use the Python shell:
./bin/pyspark
And run the following command, which should also return 1,000,000,000:
>>> spark.range(1000 * 1000 * 1000).count()
Example Programs
Spark also comes with several sample programs in the examples
directory.
To run one of them, use ./bin/run-example <class> [params]
. For example:
./bin/run-example SparkPi
will run the Pi example locally.
You can set the MASTER environment variable when running examples to submit
examples to a cluster. This can be a mesos:// or spark:// URL,
"yarn" to run on YARN, and "local" to run
locally with one thread, or "local[N]" to run locally with N threads. You
can also use an abbreviated class name if the class is in the examples
package. For instance:
MASTER=spark://host:7077 ./bin/run-example SparkPi
Many of the example programs print usage help if no params are given.
Running Tests
Testing first requires building Spark. Once Spark is built, tests can be run using:
./dev/run-tests
Please see the guidance on how to run tests for a module, or individual tests.
There is also a Kubernetes integration test, see resource-managers/kubernetes/integration-tests/README.md
A Note About Hadoop Versions
Spark uses the Hadoop core library to talk to HDFS and other Hadoop-supported storage systems. Because the protocols have changed in different versions of Hadoop, you must build Spark against the same version that your cluster runs.
Please refer to the build documentation at "Specifying the Hadoop Version and Enabling YARN" for detailed guidance on building for a particular distribution of Hadoop, including building for particular Hive and Hive Thriftserver distributions.
Configuration
Please refer to the Configuration Guide in the online documentation for an overview on how to configure Spark.
Contributing
Please review the Contribution to Spark guide for information on how to get started contributing to the project.