pingcap / pingcap/tiflash

Inconsistent cast conversion in Tiflash

Abierto
#9,653 6 comentarios 0 reacciones 0 asignados Ver en GitHub

Nadie ha tomado este issue todavía.

affects-8.4 affects-8.5 component/compute impact/inconsistency may-affects-5.4 may-affects-6.1 may-affects-6.5 may-affects-7.1 may-affects-7.5 may-affects-8.1 severity/major type/bug
Lenguaje dominante
C++
Estrellas
1k
Forks
423
Merge medio
1 d 15 h
PR fusionados (30 d)
24

Descripción

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)
Drop table if exists test_table;
CREATE TABLE test_table (
    id INT PRIMARY KEY AUTO_INCREMENT,
    col1 VARCHAR(255),
    col2 TINYINT,
    col3 SMALLINT
);

INSERT INTO test_table (col1, col2, col3) VALUES
    ('-9223372036854775809', -128, -32768),
    ('-9223372036854775808', 127, 32767);

ALTER TABLE test_table SET TIFLASH REPLICA 1;

SELECT /*+ READ_FROM_STORAGE(TIKV[test_table])*/
    id,
    col1,
    CAST(col1 AS SIGNED) AS signed_int,
    CAST(col1 AS UNSIGNED) AS unsigned_int,
    CAST(col1 AS DECIMAL(65,30)) AS decimal_value,
    CAST(col1 AS DOUBLE) AS double_value
FROM
    test_table;
    
SELECT /*+ READ_FROM_STORAGE(TIFLASH[test_table])*/
    id,
    col1,
    CAST(col1 AS SIGNED) AS signed_int,
    CAST(col1 AS UNSIGNED) AS unsigned_int,
    CAST(col1 AS DECIMAL(65,30)) AS decimal_value,
    CAST(col1 AS DOUBLE) AS double_value
FROM
    test_table;
2. What did you expect to see? (Required)

I find that unsigned_int is inconsistent across two queries.

3. What did you see instead (Required)
mysql> SELECT /*+ READ_FROM_STORAGE(TIKV[test_table])*/
    ->     id,
    ->     col1,
    ->     CAST(col1 AS SIGNED) AS signed_int,
    ->     CAST(col1 AS UNSIGNED) AS unsigned_int,
    ->     CAST(col1 AS DECIMAL(65,30)) AS decimal_value,
    ->     CAST(col1 AS DOUBLE) AS double_value
    -> FROM
    ->     test_table;
+----+----------------------+----------------------+---------------------+-----------------------------------------------------+-----------------------+
| id | col1                 | signed_int           | unsigned_int        | decimal_value                                       | double_value          |
+----+----------------------+----------------------+---------------------+-----------------------------------------------------+-----------------------+
|  1 | -9223372036854775809 | -9223372036854775808 | 9223372036854775808 | -9223372036854775809.000000000000000000000000000000 | -9.223372036854776e18 |
|  2 | -9223372036854775808 | -9223372036854775808 | 9223372036854775808 | -9223372036854775808.000000000000000000000000000000 | -9.223372036854776e18 |
+----+----------------------+----------------------+---------------------+-----------------------------------------------------+-----------------------+
2 rows in set, 4 warnings (0.01 sec)

mysql> SELECT /*+ READ_FROM_STORAGE(TIFLASH[test_table])*/     id,     col1,     CAST(col1 AS SIGNED) AS signed_int,     CAST(col1 AS UNSIGNED) AS unsigned_int,     CAST(col1 AS DECIMAL(65,30)) AS decimal_value,     CAST(col1 AS DOUBLE) AS double_value FROM
  test_table;
+----+----------------------+----------------------+---------------------+-----------------------------------------------------+-----------------------+
| id | col1                 | signed_int           | unsigned_int        | decimal_value                                       | double_value          |
+----+----------------------+----------------------+---------------------+-----------------------------------------------------+-----------------------+
|  1 | -9223372036854775809 | -9223372036854775808 |                   0 | -9223372036854775809.000000000000000000000000000000 | -9.223372036854776e18 |
|  2 | -9223372036854775808 | -9223372036854775808 | 9223372036854775808 | -9223372036854775808.000000000000000000000000000000 | -9.223372036854776e18 |
+----+----------------------+----------------------+---------------------+-----------------------------------------------------+-----------------------+
2 rows in set (0.01 sec)
4. What is your TiDB version? (Required)

TiDB v8.4.0

Guía de contribución

No hay ninguna guía de contribución indexada para este repositorio

Primeros pasos

  1. Lee el issue completo y luego la guía de contribución del proyecto.
  2. Comenta en el issue que vas a ocuparte — evita que dos personas hagan lo mismo.
  3. Haz un fork del repositorio y trabaja en una rama.
  4. Abre un pull request que haga referencia al número del issue.

Línea de trabajo

Comienza ejecutando la reproducción SQL proporcionada en TiDB v8.4.0 y compara los resultados de TIKV y TIFLASH-READ_FROM_STORAGE para CAST(col1 AS UNSIGNED). Rastrea el manejo del cast en las dos rutas de almacenamiento, centrándote en los valores límite mostrados; el trabajo estará terminado cuando ambas consultas produzcan resultados unsigned_int coherentes.

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

Evaluación

Stack tecnológico
cpp, sql
Área
databases
Tipo de issue
Error
Dificultad
4/5
Tiempo estimado
3-5 días
Estado de actividad
Estancado
Claridad
Bastante claro
Aptitud para principiantes
35/100

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