Isolate Redis blocking replay workers

[bootjp]

Author: bootjp

Summary

• add a dedicated async queue and worker limit for mutating blocking-command secondary replays
• derive blocking replay concurrency from unused secondary backend pool capacity
• keep BZPOP replay misses visible as command miss metrics without counting them as secondary write failures

Verification

• go test ./proxy -count=1
• go test ./cmd/redis-proxy -count=1
• golangci-lint run ./proxy ./cmd/redis-proxy --timeout=5m

Risk

• limits normal secondary writes plus blocking replay workers to the secondary backend pool so long blocking replays do not starve producer writes

Summary by CodeRabbit

• 新機能

  • セカンダリへのブロッキングコマンド再生に、同時実行数とキュー容量の設定を追加しました。
  • ブロッキング再生を通常の書き込み処理から分離し、通常処理のワーカーを圧迫しないよう改善しました。
  • 再生を無効化した場合は、セカンダリへの送信を停止できます。

• 改善

  • 設定値の妥当性検証を強化し、実行プール容量を超える設定を防止します。
  • 再生結果や再試行、ミスのメトリクスとエラー記録を整理しました。

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 83157d2d-592a-468f-8676-a353ee06ae3d

📥 Commits

Reviewing files that changed from the base of the PR and between e4ba106 and 9e00844.

📒 Files selected for processing (6)

• cmd/redis-proxy/main.go
• cmd/redis-proxy/main_test.go
• proxy/async_queue.go
• proxy/config.go
• proxy/dualwrite.go
• proxy/proxy_test.go

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📝 Walkthrough

Walkthrough

Secondary blocking replay に専用の設定、容量検証、セマフォ、キュー、ディスパッチャを追加し、Blocking コマンドの replay 経路と positive integer replay の結果処理を更新しています。

Changes

Blocking replay の分離実行

Layer / File(s)	Summary
Runtime オプションと容量導出 cmd/redis-proxy/main.go, cmd/redis-proxy/main_test.go, proxy/config.go	Blocking replay の CLI 設定、ProxyConfig フィールド、非負値検証、write との合計容量検証、既定同時実行数の導出を追加しています。
専用キューとディスパッチャ proxy/dualwrite.go, proxy/async_queue.go	Blocking replay 用のセマフォ・キュー・容量計算を追加し、容量がある場合のみ専用ディスパッチャを起動します。
Blocking コマンドのリプレイ経路 proxy/dualwrite.go, proxy/proxy_test.go	Mutating blocking command の replay を専用経路へ切り替え、通常 write worker の分離、無効化時の動作、既存 replay 条件をテストしています。
Positive integer replay の結果処理 proxy/dualwrite.go, proxy/proxy_test.go	結果判定とリトライ処理をヘルパへ分離し、no_effect を通常の secondary write error と区別してメトリクスへ反映します。

Estimated code review effort: 4 (Complex) | ~45 minutes

Sequence Diagram(s)

sequenceDiagram
participant Client
participant DualWriter
participant blockingReplayQueue
participant Secondary
Client->>DualWriter: Blocking command
DualWriter->>blockingReplayQueue: goBlockingReplay で replay を投入
blockingReplayQueue->>Secondary: 専用 dispatcher が replay 実行
Secondary-->>DualWriter: replay 結果
DualWriter-->>Client: Blocking 結果

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Possibly related PRs

• bootjp/elastickv#531: Secondary write の失敗記録・メトリクス処理に関連します。
• bootjp/elastickv#1134: Secondary replay のオプション検証と非同期キュー制御に関連します。

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	タイトルは Redis の blocking replay worker を分離するという PR の主目的を簡潔に表しています。
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

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• Create stacked PR
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[bootjp]

@codex review

[gemini-code-assist]

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[chatgpt-codex-connector]

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Reviewed commit:a8fd7880c1

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[chatgpt-codex-connector]

Allow one-connection secondary pools to start

When the CLI is run in a dual-write mode with -elastickv-pool-size=1 (or elastickv-primary with -primary-pool-size=1), this default derives writeConcurrency=1 and blockingReplayConcurrency=1; validateSecondaryConcurrency then rejects the config because their sum exceeds the single secondary connection. Since 0 for -secondary-blocking-replay-concurrency means “derive” and negative values are rejected, there is no CLI value that disables the new blocking replay worker, so deployments that intentionally use a single secondary backend connection can no longer start.

Useful? React with 👍 / 👎.

[bootjp]

Addressed the single-connection secondary pool case by deriving blocking replay concurrency to 0 when no secondary pool capacity remains after normal writes. Added tests for the disabled replay path.

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Swish!

Reviewed commit:9e00844e69

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