Preserve ALIAS column order for distributed reads#94644
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vdimir merged 2 commits intoClickHouse:masterfrom Jan 22, 2026
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Preserve ALIAS column order for distributed reads#94644vdimir merged 2 commits intoClickHouse:masterfrom
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Store ALIAS expressions in insertion order to keep output column ordering stable in distributed queries, and track alias names separately for membership checks.
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Workflow [PR], commit [ea1def4] Summary: ❌
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the "Bugfix validation" is checking @maxknv will you fix it? It's here: ClickHouse/ci/jobs/functional_tests.py Lines 621 to 626 in f611218 Maybe fixed here already: #94554 |
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Preserve ALIAS column order for distributed reads
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25.8.15 Stable backport of ClickHouse#94644: Preserve ALIAS column order for distributed reads
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Changelog entry (a [user-readable short description]
Fixes a bug where certain distributed queries with
ORDER BYcould returnALIAScolumns with swapped values (i.e., columnashowing columnb’s data and vice versa).Documentation entry for user-facing changes
Preserve insertion order for ALIAS expressions to keep distributed output column order stable.
Closes #86227
The problem was caused by iteration over the unordered_map added in https://github.com/ClickHouse/ClickHouse/pull/59595/changes#r2707576468
with later addition in
#78097