starocean999 opened a new pull request, #67645:
URL: https://github.com/apache/doris/pull/67645
…
### What problem does this PR solve?
Issue Number: close #xxx
Related PR: #xxx
Problem Summary:
When the `LEADING` hint is used on a FULL OUTER JOIN whose ON condition
references only one side, rows from the preserved side that fail the
conjunct are dropped instead of being output with the other side
null-extended. For example:
SELECT /*+ LEADING(a,b) */ a.p, b.q
FROM r1_a AS a FULL OUTER JOIN r1_b AS b ON a.p > 0;
with `a = {0,1}` and `b = {7}` should return `(0,NULL),(1,7)` but only
returns `(1,7)`; the symmetric case `ON b.q > 0` similarly loses
`(NULL,0)`. The wrong plan shows the predicate leaked into the input
scan (`A-side scan: PREDICATES: (p[#1] > 0)`), so the offending rows
were filtered out before the join could null-extend them.
Root cause: `CollectJoinConstraint` records every ON conjunct together
with the table bitmap of the tables it references. When the `LEADING`
hint rebuilds the join tree, `LeadingHint.makeFilterPlanIfExist` pushes
a conjunct into a scan whenever its bitmap is a subset of that scan's
table set. A LEFT JOIN conjunct that references only the preserved
(left) side is already protected from such pushdown by OR-ing its
bitmap with the nullable (right) side's bitmap (see #32286). However
`JoinType.isLeftJoin()` does not include `FULL_OUTER_JOIN`, and a FULL
OUTER JOIN preserves rows from *both* sides, so a one-sided conjunct
such as `a.p > 0` was pushed into scan `a` and deleted rows there.
Fix: in `CollectJoinConstraint`, mirror the LEFT JOIN handling for
FULL OUTER JOIN — OR the conjunct's table bitmap with *both* children's
bitmaps, so a one-sided conjunct always stays attached as the full
outer join's own condition and can never be pushed into either input.
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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