mickjermsurawong-stripe opened a new pull request #27153: [SPARK-20384][SQL] Support value class in schema of Dataset (without breaking existing current projection) URL: https://github.com/apache/spark/pull/27153 <!-- Thanks for sending a pull request! Here are some tips for you: 1. If this is your first time, please read our contributor guidelines: https://spark.apache.org/contributing.html 2. Ensure you have added or run the appropriate tests for your PR: https://spark.apache.org/developer-tools.html 3. If the PR is unfinished, add '[WIP]' in your PR title, e.g., '[WIP][SPARK-XXXX] Your PR title ...'. 4. Be sure to keep the PR description updated to reflect all changes. 5. Please write your PR title to summarize what this PR proposes. 6. If possible, provide a concise example to reproduce the issue for a faster review. --> ### What changes were proposed in this pull request? <!-- Please clarify what changes you are proposing. The purpose of this section is to outline the changes and how this PR fixes the issue. If possible, please consider writing useful notes for better and faster reviews in your PR. See the examples below. 1. If you refactor some codes with changing classes, showing the class hierarchy will help reviewers. 2. If you fix some SQL features, you can provide some references of other DBMSes. 3. If there is design documentation, please add the link. 4. If there is a discussion in the mailing list, please add the link. --> - This PR revisits https://github.com/apache/spark/pull/22309, and [SPARK-20384](https://issues.apache.org/jira/browse/SPARK-20384) solving the original problem, but additionally will prevent backward-compat break on schema of top-level `AnyVal` value class. - Why previous break? We currently support top-level value classes just as any other case class; field of the underlying type is present in schema. This means any dataframe SQL filtering on this expects the field name to be present. The previous PR changes this schema and would result in breaking current usage. See test `"schema for case class that is a value class"`. This PR keeps the schema. - We actually currently support collection of value classes prior to this change, but not case class of nested value class. This means the schema of these classes shouldn't change to prevent breaking too. See the tests asserting schema before any changes in 0cdad3b - However, what we can change, without breaking, is schema of nested value class, which will fails due to the compile problem, and thus its schema now isn't actually valid. After the change, the schema of this nested value class is now flattened: c7aaae8 - With this PR, there's flattening only for nested value class (new), but not for top-level and collection classes (existing behavior) ### Why are the changes needed? <!-- Please clarify why the changes are needed. For instance, 1. If you propose a new API, clarify the use case for a new API. 2. If you fix a bug, you can clarify why it is a bug. --> - Currently, nested value class isn't supported. This is because when the generated code treats `anyVal` class in its unwrapped form, but we encode the type to be the wrapped case class. This results in compile of generated code For example, For a given `AnyVal` wrapper and its root-level class container ``` case class IntWrapper(i: Int) extends AnyVal case class ComplexValueClassContainer(c: IntWrapper) ``` The problematic part of generated code: ``` private InternalRow If_1(InternalRow i) { boolean isNull_42 = i.isNullAt(0); // 1) The root-level case class we care org.apache.spark.sql.catalyst.encoders.ComplexValueClassContainer value_46 = isNull_42 ? null : ((org.apache.spark.sql.catalyst.encoders.ComplexValueClassContainer) i.get(0, null)); if (isNull_42) { throw new NullPointerException(((java.lang.String) references[5] /* errMsg */ )); } boolean isNull_39 = true; // 2) We specify its member to be unwrapped case class extending `AnyVal` org.apache.spark.sql.catalyst.encoders.IntWrapper value_43 = null; if (!false) { isNull_39 = false; if (!isNull_39) { // 3) ERROR: `c()` compiled however is of type `int` and thus we see error value_43 = value_46.c(); } } ``` We get this errror: Assignment conversion not possible from type "int" to type "org.apache.spark.sql.catalyst.encoders.IntWrapper" ``` java.util.concurrent.ExecutionException: org.codehaus.commons.compiler.CompileException: File 'generated.java', Line 159, Column 1: failed to compile: org.codehaus.commons.compiler.CompileException: File 'generated.java', Line 159, Column 1: Assignment conversion not possible from type "int" to type "org.apache.spark.sql.catalyst.encoders.IntWrapper" ``` ### Does this PR introduce any user-facing change? <!-- If yes, please clarify the previous behavior and the change this PR proposes - provide the console output, description and/or an example to show the behavior difference if possible. If no, write 'No'. --> - Yes, this will fix the bug. ### How was this patch tested? <!-- If tests were added, say they were added here. Please make sure to add some test cases that check the changes thoroughly including negative and positive cases if possible. If it was tested in a way different from regular unit tests, please clarify how you tested step by step, ideally copy and paste-able, so that other reviewers can test and check, and descendants can verify in the future. If tests were not added, please describe why they were not added and/or why it was difficult to add. --> - This PR ports all the tests from https://github.com/apache/spark/pull/22309 and added a few more. cc @mt40 @joshrosen-stripe
---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
