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Fix wrong result of non-correlated EXISTS.#87207

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KochetovNicolai merged 2 commits intomasterfrom
fix-exists
Sep 17, 2025
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Fix wrong result of non-correlated EXISTS.#87207
KochetovNicolai merged 2 commits intomasterfrom
fix-exists

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@KochetovNicolai KochetovNicolai commented Sep 16, 2025

Changelog category (leave one):

  • Bug Fix (user-visible misbehavior in an official stable release)

Changelog entry (a user-readable short description of the changes that goes into CHANGELOG.md):

Fix possible wrong result of non-correlated EXISTS. It was broken with execute_exists_as_scalar_subquery=1 which was introduced in #85481 and affects 25.8.
Fixes #86415

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  • Documentation is written (mandatory for new features)

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clickhouse-gh bot commented Sep 16, 2025 •
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Workflow [PR], commit [120009e]

Summary: ❌

job_name test_name status info comment
Integration tests (arm_binary, distributed plan, 1/4) failure
test_disks_app_interactive/test.py::test_disks_app_interactive_list_directories_default FAIL
test_disks_app_interactive/test.py::test_disks_app_interactive_test_move_and_write FAIL
test_dictionaries_postgresql/test.py::test_background_dictionary_reconnect FAIL

@clickhouse-gh clickhouse-gh bot added the pr-bugfix Pull request with bugfix, not backported by default label Sep 16, 2025
KochetovNicolai
KochetovNicolai commented Sep 16, 2025
View reviewed changes
src/Analyzer/Resolve/evaluateScalarSubqueryIfNeeded.cpp

executor.emplace(io.pipeline);
while (block.rows() == 0 && executor->pull(block))
while (chunk.getNumRows() == 0 && executor->pull(chunk))
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@KochetovNicolai KochetovNicolai Sep 16, 2025

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The fix is to replace Block with Chunk because an optimized for EXISTS plan may return a chunk with no columns but non-zero rows.

@novikd novikd self-assigned this Sep 16, 2025
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KochetovNicolai commented Sep 17, 2025

test_disks_app_interactive is flaky

@KochetovNicolai KochetovNicolai added this pull request to the merge queue Sep 17, 2025
Merged via the queue into master with commit f171353 Sep 17, 2025
238 of 242 checks passed
@KochetovNicolai KochetovNicolai deleted the fix-exists branch September 17, 2025 14:55
@robot-ch-test-poll2 robot-ch-test-poll2 added the pr-synced-to-cloud The PR is synced to the cloud repo label Sep 17, 2025
@robot-ch-test-poll1 robot-ch-test-poll1 mentioned this pull request Sep 17, 2025
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@robot-clickhouse-ci-2 robot-clickhouse-ci-2 added pr-backports-created-cloud deprecated label, NOOP pr-must-backport-synced The `*-must-backport` labels are synced into the cloud Sync PR labels Sep 17, 2025
robot-clickhouse-ci-2 added a commit that referenced this pull request Sep 19, 2025
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Merge pull request #87245 from ClickHouse/cherrypick/25.8/87207
3239270 
Cherry pick #87207 to 25.8: Fix wrong result of non-correlated EXISTS.
robot-clickhouse added a commit that referenced this pull request Sep 19, 2025
@robot-clickhouse
Backport #87207 to 25.8: Fix wrong result of non-correlated EXISTS.
4c08c5d
@robot-clickhouse-ci-2 robot-clickhouse-ci-2 mentioned this pull request Sep 19, 2025
Merged
@robot-clickhouse robot-clickhouse added the pr-backports-created Backport PRs are successfully created, it won't be processed by CI script anymore label Sep 19, 2025
clickhouse-gh bot added a commit that referenced this pull request Sep 19, 2025
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Merge pull request #87329 from ClickHouse/backport/25.8/87207
a415739 
Backport #87207 to 25.8: Fix wrong result of non-correlated EXISTS.
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pr-backports-created Backport PRs are successfully created, it won't be processed by CI script anymore pr-backports-created-cloud deprecated label, NOOP pr-bugfix Pull request with bugfix, not backported by default pr-must-backport-synced The `*-must-backport` labels are synced into the cloud Sync PR pr-synced-to-cloud The PR is synced to the cloud repo v25.8-must-backport

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'SELECT EXISTS' query incorrectly produces 0 on ClickHouse 25.8.1

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