第二阶段优化已完成，重点是提高后台任务吞吐并降低 Outbox 数据库开销。

RabbitMQ 默认从单一回调通道提升为三类任务独立并行，跨类型并发能力由 1 提升到 3；每类还能独立配置 1–16 个消费者。[RabbitMqBackgroundJobs.cs (line 143)](E:/jiaowu/src/Jiaowu.Api/Infrastructure/BackgroundJobs/RabbitMqBackgroundJobs.cs:143) InMemory 开发模式同步改为按任务类型隔离队列，避免某类长任务堵塞其他任务。租约恢复检查从“每发布一条执行一次”改为默认每 60 秒维护一次。启动恢复改为数据库 NOT EXISTS 查询，不再把全部历史 Outbox 加载进内存。[BackgroundJobOutboxPublisher.cs (line 9)](E:/jiaowu/src/Jiaowu.Api/Infrastructure/BackgroundJobs/BackgroundJobOutboxPublisher.cs:9) 完成消息默认保留 14 天，之后按每批 500 条清理，并增加对应组合索引。 /health/messaging 现在返回各状态积压量、过期租约和最老任务等待时间。[BackgroundJobMonitoringService.cs (line 16)](E:/jiaowu/src/Jiaowu.Api/Infrastructure/BackgroundJobs/BackgroundJobMonitoringService.cs:16) 新增 Jiaowu.BackgroundJobs 运行时指标，覆盖发布量、处理量、发布耗时、处理耗时和清理量。[BackgroundJobTelemetry.cs (line 9)](E:/jiaowu/src/Jiaowu.Api/Infrastructure/BackgroundJobs/BackgroundJobTelemetry.cs:9) 配置、Compose 和调优建议已更新。[README.md (line 257)](E:/jiaowu/README.md:257)
2026-07-26 21:05:18 +08:00
parent 6300645120
commit 034f1eacb8
21 changed files with 579 additions and 135 deletions
@@ -0,0 +1,56 @@
+using Jiaowu.Api.Domain.System;
+using Jiaowu.Api.Infrastructure.Persistence;
+using Microsoft.EntityFrameworkCore;
+
+namespace Jiaowu.Api.Infrastructure.BackgroundJobs;
+
+public sealed record BackgroundJobBacklogSnapshot(
+    int Pending,
+    int Publishing,
+    int Published,
+    int Processing,
+    int ExpiredLeases,
+    DateTime? OldestUnfinishedAt,
+    double? OldestUnfinishedAgeSeconds);
+
+public sealed class BackgroundJobMonitoringService(AppDbContext db)
+{
+    public async Task<BackgroundJobBacklogSnapshot> GetSnapshotAsync(
+        CancellationToken cancellationToken)
+    {
+        var counts = await db.BackgroundJobOutboxMessages.AsNoTracking()
+            .Where(x => x.State != BackgroundJobOutboxState.Completed)
+            .GroupBy(x => x.State)
+            .Select(group => new { State = group.Key, Count = group.Count() })
+            .ToListAsync(cancellationToken);
+        var countByState = counts.ToDictionary(x => x.State, x => x.Count);
+        var now = DateTime.UtcNow;
+        var expiredLeases = await db.BackgroundJobOutboxMessages.AsNoTracking()
+            .CountAsync(
+                x => (x.State == BackgroundJobOutboxState.Publishing ||
+                      x.State == BackgroundJobOutboxState.Processing) &&
+                     x.LeaseExpiresAt != null &&
+                     x.LeaseExpiresAt < now,
+                cancellationToken);
+        var oldestUnfinishedAt = await db.BackgroundJobOutboxMessages
+            .AsNoTracking()
+            .Where(x => x.State != BackgroundJobOutboxState.Completed)
+            .Select(x => (DateTime?)x.CreatedAt)
+            .MinAsync(cancellationToken);
+        double? ageSeconds = oldestUnfinishedAt.HasValue
+            ? Math.Max(0, (now - oldestUnfinishedAt.Value).TotalSeconds)
+            : null;
+
+        return new BackgroundJobBacklogSnapshot(
+            GetCount(BackgroundJobOutboxState.Pending),
+            GetCount(BackgroundJobOutboxState.Publishing),
+            GetCount(BackgroundJobOutboxState.Published),
+            GetCount(BackgroundJobOutboxState.Processing),
+            expiredLeases,
+            oldestUnfinishedAt,
+            ageSeconds);
+
+        int GetCount(BackgroundJobOutboxState state) =>
+            countByState.GetValueOrDefault(state);
+    }
+}