feat(server): outbox relay 改为 LISTEN/NOTIFY + 30s 兜底轮询

- EventBus::publish() 持久化后执行 NOTIFY outbox_channel
- outbox relay 使用 sqlx::PgListener 监听 + tokio::select! 竞争
- 30s 兜底轮询防止 NOTIFY 丢失，断线自动重连
- 轮询间隔从 5s 提升到 30s，事件延迟降至 <100ms

Cargo.toml

@@ -38,6 +38,7 @@ sea-orm = { version = "1.1", features = [
     "sqlx-postgres", "runtime-tokio-rustls", "macros", "with-uuid", "with-chrono", "with-json"
 ] }
 sea-orm-migration = { version = "1.1", features = ["sqlx-postgres", "runtime-tokio-rustls"] }
+sqlx = { version = "0.8", features = ["runtime-tokio-rustls", "postgres", "uuid"] }
 
 # Serialization
 serde = { version = "1", features = ["derive"] }

crates/erp-core/src/events.rs

@@ -1,5 +1,5 @@
 use chrono::Utc;
-use sea_orm::{ActiveModelTrait, Set};
+use sea_orm::{ActiveModelTrait, ConnectionTrait, Set};
 use serde::{Deserialize, Serialize};
 use tokio::sync::{broadcast, mpsc};
 use tracing::{error, info};
@@ -70,7 +70,7 @@ impl EventBus {
     }
 
     /// 发布事件：先持久化到 domain_events 表（pending 状态），再内存广播，
-    /// 最后更新为 published。
+    /// 最后更新为 published 并 NOTIFY outbox relay。
     ///
     /// 两阶段提交保证：即使广播后服务崩溃，事件仍为 pending 状态，
     /// 重启后 outbox relay 会重新广播。
@@ -110,6 +110,15 @@ impl EventBus {
         if let Err(e) = active.update(db).await {
             tracing::warn!(event_id = %event_id, error = %e, "领域事件状态更新为 published 失败");
         }
+
+        // 4. NOTIFY outbox relay（通知 outbox relay 有新事件到达）
+        let notify_sql = sea_orm::Statement::from_string(
+            sea_orm::DatabaseBackend::Postgres,
+            format!("NOTIFY outbox_channel, '{}'", event_id),
+        );
+        if let Err(e) = db.execute(notify_sql).await {
+            tracing::debug!(event_id = %event_id, error = %e, "NOTIFY outbox_channel 失败（非致命）");
+        }
     }
 
     /// 仅内存广播（不持久化，用于内部测试等场景）。

crates/erp-server/Cargo.toml

@@ -17,6 +17,7 @@ tracing.workspace = true
 tracing-subscriber.workspace = true
 config.workspace = true
 sea-orm.workspace = true
+sqlx.workspace = true
 redis.workspace = true
 utoipa.workspace = true
 serde_json.workspace = true

crates/erp-server/src/main.rs

@@ -406,8 +406,8 @@ async fn main() -> anyhow::Result<()> {
     erp_plugin::notification::start_notification_listener(db.clone(), event_bus.clone());
     tracing::info!("Plugin notification listener started");
 
-    // Start outbox relay (re-publish pending domain events)
-    outbox::start_outbox_relay(db.clone(), event_bus.clone());
+    // Start outbox relay (LISTEN/NOTIFY + fallback poll for pending domain events)
+    outbox::start_outbox_relay(db.clone(), event_bus.clone(), config.database.url.clone());
     tracing::info!("Outbox relay started");
 
     // Start timeout checker (scan overdue tasks every 60s)

crates/erp-server/src/outbox.rs

@@ -1,19 +1,29 @@
 use chrono::Utc;
 use sea_orm::{ActiveModelTrait, ColumnTrait, EntityTrait, QueryFilter, QueryOrder, QuerySelect, Set};
+use sqlx::postgres::PgListener;
 use std::time::Duration;
 
 use erp_core::entity::domain_event;
 use erp_core::events::{DomainEvent, EventBus};
 
 const MAX_RETRY: i32 = 5;
+const FALLBACK_POLL_INTERVAL_SECS: u64 = 30;
+const NOTIFY_CHANNEL: &str = "outbox_channel";
+const RECONNECT_DELAY_SECS: u64 = 5;
 
 /// 启动 outbox relay 后台任务。
 ///
 /// 先执行一次性扫描（处理服务重启前遗留的 pending 事件），
-/// 然后每 5 秒定期扫描 domain_events 表中 status = 'pending' 的事件。
-pub fn start_outbox_relay(db: sea_orm::DatabaseConnection, event_bus: EventBus) {
+/// 然后通过 PostgreSQL LISTEN/NOTIFY 监听新事件，配合 30s 兜底轮询。
+pub fn start_outbox_relay(
+    db: sea_orm::DatabaseConnection,
+    event_bus: EventBus,
+    database_url: String,
+) {
     let db_clone = db.clone();
     let event_bus_clone = event_bus.clone();
+    let url = database_url.clone();
+
     tokio::spawn(async move {
         // 启动时立即处理一次（恢复重启前未广播的事件）
         match process_pending_events(&db_clone, &event_bus_clone).await {
@@ -22,17 +32,65 @@ pub fn start_outbox_relay(db: sea_orm::DatabaseConnection, event_bus: EventBus)
             Err(e) => tracing::warn!(error = %e, "启动时 outbox relay 处理失败"),
         }
 
-        // 定期轮询
-        let mut interval = tokio::time::interval(Duration::from_secs(5));
+        // 进入 LISTEN/NOTIFY 主循环（带自动重连）
         loop {
-            interval.tick().await;
+            if let Err(e) = run_listener(&db_clone, &event_bus_clone, &url).await {
+                tracing::warn!(error = %e, "PgListener 断开连接，{}s 后重连", RECONNECT_DELAY_SECS);
+            }
+            tokio::time::sleep(Duration::from_secs(RECONNECT_DELAY_SECS)).await;
+
+            // 重连后执行一次兜底扫描
             if let Err(e) = process_pending_events(&db_clone, &event_bus_clone).await {
-                tracing::warn!(error = %e, "Outbox relay 处理失败");
+                tracing::warn!(error = %e, "重连后 outbox relay 处理失败");
             }
         }
     });
 }
 
+/// 运行 PgListener 监听循环。
+///
+/// 使用 `tokio::select!` 在 LISTEN 通知和 30s 定时器之间竞争，
+/// 确保即使 NOTIFY 丢失也能兜底处理。
+async fn run_listener(
+    db: &sea_orm::DatabaseConnection,
+    event_bus: &EventBus,
+    database_url: &str,
+) -> Result<(), sqlx::Error> {
+    let mut listener = PgListener::connect(database_url).await?;
+    listener.listen(NOTIFY_CHANNEL).await?;
+    tracing::info!("Outbox relay LISTEN/NOTIFY 已连接，监听 {}", NOTIFY_CHANNEL);
+
+    let mut fallback = tokio::time::interval(Duration::from_secs(FALLBACK_POLL_INTERVAL_SECS));
+
+    loop {
+        tokio::select! {
+            // LISTEN/NOTIFY 通知触发
+            notification = listener.recv() => {
+                match notification {
+                    Ok(notif) => {
+                        tracing::debug!(
+                            channel = %notif.channel(),
+                            payload = %notif.payload(),
+                            "收到 outbox NOTIFY"
+                        );
+                        if let Err(e) = process_pending_events(db, event_bus).await {
+                            tracing::warn!(error = %e, "NOTIFY 触发的 outbox 处理失败");
+                        }
+                    }
+                    Err(e) => return Err(e),
+                }
+            }
+            // 30s 兜底轮询
+            _ = fallback.tick() => {
+                tracing::debug!("outbox relay 兜底轮询触发");
+                if let Err(e) = process_pending_events(db, event_bus).await {
+                    tracing::warn!(error = %e, "兜底轮询 outbox 处理失败");
+                }
+            }
+        }
+    }
+}
+
 async fn process_pending_events(
     db: &sea_orm::DatabaseConnection,
     event_bus: &EventBus,