ClickHouse / ClickHouse/clickhouse-java
[client-v2, jdbc-v2] Make execution TIMEOUT error optionally retriable
- Lenguaje dominante
- Java
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- 2 d 23 h
- PR fusionados (30 d)
- 29
Descripción
## Description
Current `159, TIMEOUT_EXCEEDED` is retried unconditionally. It should be a dedicated failure cause selectable per operation because different queries need different behavior:
| Query Type | Scenario | Retriable? | Recommended Action |
| :--- | :--- | :---: | :--- |
| **`SELECT`** | Pure read operations | **Yes** | Retry with exponential backoff or redirect to a replica node. |
| **`SELECT`** | Heavy unoptimized query hitting `max_execution_time` | **No** | Do not retry under identical settings. Increase `max_execution_time` or rewrite query. |
| **`INSERT`** | MergeTree tables with deduplication active (`insert_deduplicate = 1`) | **Yes** | Safe to retry using the exact same data block structure. |
| **`INSERT`** | Tables without block deduplication | **No** | **Unsafe.** Partial blocks may have been written; retrying risks duplicate rows. Check table state first. |
| **`DDL / Mutations`** | `ALTER`, `OPTIMIZE`, or background mutations | **No** | Inspect system tables (`system.mutations`, `system.merges`) before re-executing. |
Guía de contribución
Línea de trabajo
Start by tracing TIMEOUT_EXCEEDED handling in client-v2 and jdbc-v2, especially how the 159 failure is currently retried. Compare operation handling for SELECT, INSERT, and DDL or mutations, then determine where per-operation retry selection belongs. Done means timeout retry behavior can differ by operation and reflects the safety distinctions described in the table.
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Evaluación
- Stack tecnológico
- java
- Área
- api, databases
- Tipo de issue
- Nueva funcionalidad
- Dificultad
- 4/5
- Tiempo estimado
- 3-5 días
- Estado de actividad
- Activo
- Claridad
- Bastante claro
- Aptitud para principiantes
- 48/100