fix: skip dynamic filter pushdown for null-aware anti joins with a nullable build key - #23173
Merged
Merged
Conversation
github-actions
Bot
added
sqllogictest
Contributor
|
@mdashti |
neilconway
self-requested a review
July 11, 2026 13:05
Contributor
|
@mdashti Can you resolve the CI failures when you get a chance? |
The pushed filter can empty the probe. A null-aware `LeftAnti` then reads it as an empty subquery and emits build-side NULLs that should be dropped. A NOT NULL build key is unaffected.
Indexing on[0] leaned on the single-key invariant without saying so. Iterating all keys survives a future multi-key relaxation. In addition, added allow/reject unit tests to pin both directions of the guard.
The guard removes the probe-side dynamic filter from these plans.
mdashti
force-pushed
the
moe/null-aware-build-null
branch
from
July 20, 2026 17:23
32ead3e to
e512368
Compare
Contributor
Author
|
@kosiew @neilconway the failures were stale |
Codecov Report❌ Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #23173 +/- ##
==========================================
- Coverage 80.70% 80.70% -0.01%
==========================================
Files 1089 1089
Lines 368038 368096 +58
Branches 368038 368096 +58
==========================================
+ Hits 297031 297067 +36
- Misses 53308 53325 +17
- Partials 17699 17704 +5 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
|
Contributor
|
run benchmark tpch |
|
🤖 Benchmark running (GKE) | trigger CPU Details (lscpu)Comparing moe/null-aware-build-null (e512368) to 4184b07 (merge-base) diff using: tpch File an issue against this benchmark runner |
|
🤖 Benchmark completed (GKE) | trigger Instance: CPU Details (lscpu)Details
Resource Usagetpch — base (merge-base)
tpch — branch
File an issue against this benchmark runner |
kosiew
approved these changes
Jul 23, 2026
alamb
reviewed
Jul 26, 2026
| return false; | ||
| } | ||
|
|
||
| // A null-aware anti join emits a build-side NULL only when the probe |
Contributor
There was a problem hiding this comment.
the comment says anto-join but the check isn't for join type. I wonder if that is a discrepancy?
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
6 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Which issue does this close?
NOT IN+ dynamic filters + build-side NULL returns incorrect results #23126.Rationale for this change
x NOT IN (subquery)plans to a null-awareLeftAntihash join (build = outerx, probe = subquery). Join dynamic filter pushdown pushes a bounds + membership filter, built from the build keys, onto the probe scan. That filter can prune every probe row. A null-awareLeftAntireads an empty probe as a genuinely-empty subquery, so it emits build-side NULL rows that should drop:NULL NOT IN (non-empty)is UNKNOWN, not TRUE.The result is scan-dependent, so it's a silent correctness bug. A
VALUESscan ignores the pushed filter and stays correct; a parquet scan applies it and is wrong.#23103 (the probe-side NULL drop) is orthogonal; this is the build-side NULL.
What changes are included in this PR?
Skip join dynamic filter pushdown for a null-aware anti join when the build key can be NULL. The build-side NULL emission depends on whether the probe is truly empty, which the pushed filter can change by emptying it. A NOT NULL build key has no such NULL, so it keeps the pushdown.
The check is static: a schema-nullable build key disables the pushdown even when the data contains no NULLs. A runtime alternative (keep the pushdown and neutralize the filter only when the build actually holds a NULL key) would restore the optimization for those cases. I'd leave that as a follow-up.
Are these changes tested?
Yes. A
push_down_filter_parquet.sltcase reproduces it (build-side NULL, a non-matching parquet probe) and asserts the single correct row. Without the change it returns the extra NULL. In addition, unit tests pin both directions of the guard: a nullable build key rejects the pushdown and a NOT NULL build key keeps it.Are there any user-facing changes?
NOT INover a parquet (or otherwise prunable) scan with a nullable outer key now returns correct results. Such joins lose the dynamic filter pushdown.