Ngone51 opened a new pull request #29432:
URL: https://github.com/apache/spark/pull/29432
<!--
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.
-->
Use the `LinkedHashMap` instead of `immutable.Map` to hold the `Window`
expressions in `ExtractWindowExpressions.addWindow`.
### 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.
-->
This is a bug fix for https://github.com/apache/spark/pull/29270. In that
PR, the generated plan(especially for the queries q47, q49, q57) on Jenkins
always can not match the golden plan generated on my laptop.
It happens because `ExtractWindowExpressions.addWindow` now uses
`immutable.Map` to hold the `Window` expressions by the key
`(spec.partitionSpec, spec.orderSpec, WindowFunctionType.functionType(expr))`
and converts the map to `Seq` at the end. Then, the `Seq` is used to add Window
operators on top of the child plan. However, for the same query, the order of
Windows expression inside the `Seq` could be undetermined when the expression
id changes(which can affect the key). As a result, the same query could have
different plans because of the undetermined order of Window operators.
Therefore, we use `LinkedHashMap`, which records the insertion order of
entries, to make the adding order determined.
### 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'.
-->
Maybe yes, users now always see the same plan for the same queries with
multiple Window operators.
### 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.
-->
It's really hard to make a reproduce demo. I just tested manually with
https://github.com/apache/spark/pull/29270 and it looks good.
----------------------------------------------------------------
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]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
