Scalar subquery in a VALUES row fails with "Internal error: ScalarSubqueryExpr evaluated before the subquery was executed"

Abierto
#27,328 0 comentarios 0 reacciones 0 asignados Ver en GitHub

Los mantenedores suelen responder en 1 día

@v28k ya está trabajando en esto.

Desde el 11/11/2026.

Evaluación

Dificultad
4/5
Tiempo estimado
3-5 días
Aptitud para principiantes
25/100
Tipo de issue
Error
Claridad
Bien especificado
Estado de actividad
Estancado
Stack tecnológico
rust, sql
Área
databases

Línea de trabajo

Start by reading LogicalPlan::Values and MemorySourceConfig::try_new_as_values, then trace how ScalarSubqueryExpr is evaluated by ScalarSubqueryExec. Add regression coverage for the three SQL examples, including the expected (1, 5) result and inserted row. A linked pull request is already open, so this work is underway.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

bug
Describe the bug

A VALUES clause whose rows contain an uncorrelated scalar subquery fails during physical planning with an internal error:

Internal error: ScalarSubqueryExpr evaluated before the subquery was executed. This issue was likely caused by a bug in DataFusion's code.

LogicalPlan::Values is processed by MemorySourceConfig::try_new_as_values, which attempts to evaluate every row expression while the physical plan is built. Under physical scalar subquery execution, an uncorrelated scalar subquery is represented as a ScalarSubqueryExpr, which expects execution-time evaluation inside ScalarSubqueryExec. Because the subquery has not yet run at planning time, evaluation fails with an internal error.

To Reproduce

VALUES ((SELECT 1), 5);
SELECT * FROM (VALUES ((SELECT min(x) FROM (VALUES (1), (2)) AS v(x)), 5)) AS t(a, b);
CREATE TABLE v (a BIGINT, b BIGINT);
INSERT INTO v VALUES ((SELECT 1), 5);

Expected behavior

The first two SELECT queries should return (1, 5). The INSERT statement should insert one row (1, 5) into table v.

Additional context

Reproduced on main at commit bc86321 (57.0.0-dev) and with datafusion-python 55.0.0. Found using an automated grammar-based SQL fuzzer.

Willingness to contribute

I plan to contribute a fix for this bug independently

Lenguaje dominante
Rust
Estrellas
9.6k
Forks
2.6k
Merge medio
3 d 4 h
PR fusionados (30 d)
345

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