cloud-fan opened a new pull request #31930: URL: https://github.com/apache/spark/pull/31930
forward-port https://github.com/apache/spark/pull/31811 to master <!-- 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. 7. If you want to add a new configuration, please read the guideline first for naming configurations in 'core/src/main/scala/org/apache/spark/internal/config/ConfigEntry.scala'. --> ### 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. --> For permanent views (and the new SQL temp view in Spark 3.1), we store the view SQL text and re-parse/analyze the view SQL text when reading the view. In the case of `SELECT * FROM ...`, we want to avoid view schema change (e.g. the referenced table changes its schema) and will record the view query output column names when creating the view, so that when reading the view we can add a `SELECT recorded_column_names FROM ...` to retain the original view query schema. In Spark 3.1 and before, the final SELECT is added after the analysis phase: https://github.com/apache/spark/blob/branch-3.1/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/view.scala#L67 If the view query has duplicated output column names, we always pick the first column when reading a view. A simple repro: ``` scala> sql("create view c(x, y) as select 1 a, 2 a") res0: org.apache.spark.sql.DataFrame = [] scala> sql("select * from c").show +---+---+ | x| y| +---+---+ | 1| 1| +---+---+ ``` In the master branch, we will fail at the view reading time due to https://github.com/apache/spark/commit/b891862fb6b740b103d5a09530626ee4e0e8f6e3 , which adds the final SELECT during analysis, so that the query fails with `Reference 'a' is ambiguous` This PR proposes to resolve the view query output column names from the matching attributes by ordinal. For example, `create view c(x, y) as select 1 a, 2 a`, the view query output column names are `[a, a]`. When we reading the view, there are 2 matching attributes (e.g.`[a#1, a#2]`) and we can simply match them by ordinal. A negative example is ``` create table t(a int) create view v as select *, 1 as col from t replace table t(a int, col int) ``` When reading the view, the view query output column names are `[a, col]`, and there are two matching attributes of `col`, and we should fail the query. See the tests for details. ### 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. --> bug fix ### Does this PR introduce _any_ user-facing change? <!-- Note that it means *any* user-facing change including all aspects such as the documentation fix. 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 possible, please also clarify if this is a user-facing change compared to the released Spark versions or within the unreleased branches such as master. If no, write 'No'. --> yes ### 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. --> new test -- 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. 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