ClickHouse / ClickHouse/clickhouse-java
[client-v2, jdbc-v2] Make execution TIMEOUT error optionally retriable
- 主要言語
- Java
- スター
- 1.6k
- フォーク
- 636
- 平均マージ
- 2日 23時間
- マージ済み PR(30日)
- 29
説明
## 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. |
コントリビューションガイド
調査の方向性
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.
索引モデルが issue の本文から書いたものです。
評価
- 技術スタック
- java
- 領域
- api, databases
- issue の種類
- 機能追加
- 難易度
- 4/5
- 見積もり時間
- 3〜5日
- 活発さ
- 活発
- 明瞭さ
- おおむね明確
- 初心者へのやさしさ
- 48/100