Fix logical error when using LIMIT BY with distributed tables and optimize_const_name_size#95017
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alexey-milovidov merged 2 commits intomasterfrom Jan 24, 2026
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…e_const_name_size The `ReplaceLongConstWithScalarVisitor` in `buildQueryTreeForShard` was replacing constant nodes with `__getScalar` function nodes for efficient query distribution. It correctly skipped LIMIT and OFFSET clauses, but did not skip LIMIT BY LIMIT and LIMIT BY OFFSET clauses. When the query planner later accessed `getLimitByLimit()->as<ConstantNode &>()`, it failed with "Bad cast from type DB::FunctionNode to DB::ConstantNode" because the node had been replaced with a function node. The fix adds checks to also skip `getLimitByLimit` and `getLimitByOffset` nodes in the visitor's `needChildVisit` method. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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Workflow [PR], commit [d4b0f39] Summary: ❌
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ahmadov
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Jan 24, 2026
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The
ReplaceLongConstWithScalarVisitorinbuildQueryTreeForShardwas replacing constant nodes with__getScalarfunction nodes for efficient query distribution. It correctly skipped LIMIT and OFFSET clauses, but did not skip LIMIT BY N and LIMIT BY N OFFSET M clauses.When the query planner later accessed
getLimitByLimit()->as<ConstantNode &>(), it failed with "Bad cast from type DB::FunctionNode to DB::ConstantNode" because the node had been replaced with a function node.The fix adds checks to also skip
getLimitByLimitandgetLimitByOffsetnodes in the visitor'sneedChildVisitmethod.Changelog category (leave one):
See https://fiddle.clickhouse.com/af71a873-863c-4182-8ef2-78207375ba25
Closes #93322
Closes #89607