starocean999 opened a new pull request, #65095:
URL: https://github.com/apache/doris/pull/65095

   Related PR: https://github.com/apache/doris/pull/48502
   
   Problem Summary:
   
   The SetPreAggStatus rule uses a bottom-up traversal to determine whether
   pre-aggregation can be enabled for OlapScan nodes. The original 
implementation
   used a `Stack<PreAggInfoContext>` as the traversal context, which had a
   fundamental flaw: multiple scan nodes under sibling subtrees (e.g., both 
sides
   of a Join) incorrectly shared the same stack-level context.
   
   This caused two problems:
   1. A scan could inherit filter/join/project information from unrelated 
branches
      of the plan tree.
   2. To work around this, `visitLogicalAggregate` used `retainAll()` to filter 
out
      scan nodes that were not actually children of the current aggregate — an
      inelegant patch that partially masked the underlying issue.
   
   Root cause: The stack-based context could not guarantee a one-to-one
   correspondence between a scan node and its nearest aggregate ancestor.
   
   Fix: Replace the `Stack<PreAggInfoContext>` with a `Map<RelationId,
   PreAggInfoContext>`, where each scan node gets its own dedicated context 
entry.
   Each visitor method uses a snapshot-diff pattern:
   
     1. Snapshot the current map keys before visiting children
     2. Visit children (they add scan contexts to the map)
     3. Diff to identify which scans were added by this subtree
     4. Apply node-specific info only to those scans
   
   At `LogicalAggregate`, child scan contexts are consumed (removed from the 
map)
   and their results are stored — no more `retainAll()` filtering needed.
   
   
   None
   
   ### Check List (For Author)
   
   - Test <!-- At least one of them must be included. -->
       - [ ] Regression test
       - [ ] Unit Test
       - [ ] Manual test (add detailed scripts or steps below)
       - [ ] No need to test or manual test. Explain why:
           - [ ] This is a refactor/code format and no logic has been changed.
           - [ ] Previous test can cover this change.
           - [ ] No code files have been changed.
           - [ ] Other reason <!-- Add your reason?  -->
   
   - Behavior changed:
       - [ ] No.
       - [ ] Yes. <!-- Explain the behavior change -->
   
   - Does this need documentation?
       - [ ] No.
       - [ ] Yes. <!-- Add document PR link here. eg: 
https://github.com/apache/doris-website/pull/1214 -->
   
   ### Check List (For Reviewer who merge this PR)
   
   - [ ] Confirm the release note
   - [ ] Confirm test cases
   - [ ] Confirm document
   - [ ] Add branch pick label <!-- Add branch pick label that this PR should 
merge into -->
   
   


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