UPDATE / DELETE fail with "No field named __common_expr_1" when SET or WHERE repeats an expression

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@v28k 已经在做这个了。

开始于 2026年11月8日。

  • #27236 来自 @v28k —— 未关闭

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难度
4/5
预计耗时
3-5 天
新手友好度
20/100
Issue 类型
缺陷
描述清晰度
描述清楚
活跃度
停滞
技术栈
rust
领域
backend-api-design, databases

调研方向

Start by tracing extract_update_assignments and extract_dml_filters in the physical planner, then follow how common subexpression elimination moves expressions into projections. Check the UPDATE and DELETE planning paths against the table provider's schema. Done means the three reproduced statements execute without the missing __common_expr_N schema error and produce the expected row changes.

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描述

bug
Describe the bug

An UPDATE or DELETE on an in-memory table fails at planning time with a schema error regarding an internal column when its SET expressions or WHERE clause contain the same expression more than once (for example, COALESCE(c0, 0) on an INT column, where the column is coerced/cast to Int64 twice to match the integer literal):

UPDATE operation on table 't' caused by Schema error: No field named __common_expr_1. Valid fields are c0, c1.

Common subexpression elimination moves the repeated expression into an underlying projection below the UPDATE assignment projection (or below the Filter node). When the physical planner extracts the assignments (extract_update_assignments) and filters (extract_dml_filters) and hands them to the table provider, the provider evaluates them directly against the table's schema, where __common_expr_1 does not exist.

To Reproduce

CREATE TABLE t (c0 INT, c1 VARCHAR);
INSERT INTO t VALUES (1, 'a'), (NULL, 'b');

UPDATE t SET c0 = COALESCE(c0, 0); -- Schema error: No field named __common_expr_1
UPDATE t SET c1 = 'z' WHERE COALESCE(c0, 0) > 0 AND COALESCE(c0, 0) < 5; -- Schema error: No field named __common_expr_N
DELETE FROM t WHERE COALESCE(c0, 0) > 0 AND COALESCE(c0, 0) < 5; -- Schema error: No field named __common_expr_N

Expected behavior

The first UPDATE should update 2 rows ((1, 'a'), (0, 'b')). The second UPDATE should update 1 row, and the DELETE should delete 1 row. The same expressions execute without error in a SELECT.

Additional context

Reproduced on main at commit bc86321 (57.0.0-dev) and with datafusion-python 55.0.0. Found via an automated SQL fuzzer comparing execution plans.

Willingness to contribute

I plan to contribute a fix for this bug independently

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