分散刷新后补上备机同步

原实现中「全量刷新 → 通知备机同步」是同一步的两个动作：refreshAll()
由调用方跟一次 requestSubscriptionSync()。改为按账号分散刷新后，调度器
自己没有触发同步，刷新出的新缓存要等到下一次周期同步才可能送到备机。

生产上每 60 秒有一次周期同步兜底，所以影响被限制在最长约一分钟的滞后；
但这属于重构时漏掉的语义，且一旦把周期同步间隔调大就会变成真实缺口，
因此仍按原语义在刷新到内容后立即触发同步。没有账号到期时不打扰备机。

测试 441 通过。

src/main/java/com/lion/lionwebsite/Service/SubscriptionRefreshScheduler.java

@@ -38,6 +38,7 @@ public class SubscriptionRefreshScheduler {
     private final SubscriptionRefreshService refreshService;
     private final SubscriptionRefreshPlanner planner;
     private final PushService pushService;
+    private final RemoteService remoteService;
 
     /** 单个 tick 最多刷新几个账号，避免重启后一批到期账号同时开火。 */
     @Value("${subscription.refresh.max-per-tick:2}")
@@ -53,11 +54,13 @@ public class SubscriptionRefreshScheduler {
     public SubscriptionRefreshScheduler(SubMapper subMapper,
                                         SubscriptionRefreshService refreshService,
                                         SubscriptionRefreshPlanner planner,
-                                        PushService pushService) {
+                                        PushService pushService,
+                                        RemoteService remoteService) {
         this.subMapper = subMapper;
         this.refreshService = refreshService;
         this.planner = planner;
         this.pushService = pushService;
+        this.remoteService = remoteService;
     }
 
     /**
@@ -97,6 +100,10 @@ public class SubscriptionRefreshScheduler {
             refreshed++;
         }
         reportStale(enabled, now);
+        // 缓存内容变了就要让备机同步。原先全量刷新后由调用方跟一次同步，
+        // 改为分散刷新后必须在这里补上，否则备机要等到下一次周期同步才拿到新内容。
+        if (refreshed > 0)
+            remoteService.requestSubscriptionSync();
         return refreshed;
     }
 

src/test/java/com/lion/lionwebsite/Service/SubscriptionRefreshSchedulerTest.java

@@ -35,12 +35,14 @@ class SubscriptionRefreshSchedulerTest {
     private SubMapper subMapper;
     private SubscriptionRefreshService refreshService;
     private PushService pushService;
+    private RemoteService remoteService;
 
     @BeforeEach
     void setUp() {
         subMapper = mock(SubMapper.class);
         refreshService = mock(SubscriptionRefreshService.class);
         pushService = mock(PushService.class);
+        remoteService = mock(RemoteService.class);
     }
 
     /** 用固定时钟构造，使「现在」可控。 */
@@ -49,7 +51,7 @@ class SubscriptionRefreshSchedulerTest {
                 Clock.fixed(instant, ZONE), new Random(42),
                 Duration.ofHours(24), Duration.ofHours(1), Duration.ofMinutes(5));
         SubscriptionRefreshScheduler scheduler = new SubscriptionRefreshScheduler(
-                subMapper, refreshService, planner, pushService);
+                subMapper, refreshService, planner, pushService, remoteService);
         scheduler.maxPerTick = 2;
         scheduler.staleAlertMultiplier = 2.0;
         return scheduler;
@@ -385,6 +387,31 @@ class SubscriptionRefreshSchedulerTest {
                 "铺开的计划应写回内存对象");
     }
 
+    /**
+     * 刷新成功后必须通知备机同步。
+     * 原先「全量刷新」由调用方跟一次同步；改成按账号分散刷新后，若调度器不自己触发，
+     * 备机就要等到下一次周期同步才拿到新内容——这个缺口在重构时很容易漏掉。
+     */
+    @Test
+    void refreshTriggersStandbySyncWhenSomethingChanged() {
+        existing(account(1, BASE.toEpochMilli() - MINUTE, BASE.toEpochMilli() - 2 * HOUR));
+        refreshSucceedsForAll();
+
+        scheduler().refreshDueAccounts();
+
+        verify(remoteService).requestSubscriptionSync();
+    }
+
+    /** 本轮没有任何账号到期时不应打扰备机。 */
+    @Test
+    void noRefreshMeansNoStandbySync() {
+        existing(account(1, BASE.toEpochMilli() + 5 * HOUR, BASE.toEpochMilli()));
+
+        scheduler().refreshDueAccounts();
+
+        verify(remoteService, never()).requestSubscriptionSync();
+    }
+
     /** 已有计划的账号不应被重新排程，否则每次 tick 都会打乱分散效果。 */
     @Test
     void existingScheduleIsNotOverwritten() {

src/test/java/com/lion/lionwebsite/Service/SubscriptionRefreshWiringTest.java

@@ -44,6 +44,11 @@ class SubscriptionRefreshWiringTest {
             return mock(PushService.class);
         }
 
+        @Bean
+        RemoteService remoteService() {
+            return mock(RemoteService.class);
+        }
+
         @Bean
         SubscriptionRefreshPlanner subscriptionRefreshPlanner() {
             return new SubscriptionRefreshPlanner(java.time.Clock.systemDefaultZone(), new java.util.Random(),
@@ -54,8 +59,9 @@ class SubscriptionRefreshWiringTest {
         SubscriptionRefreshScheduler subscriptionRefreshScheduler(SubMapper subMapper,
                                                                  SubscriptionRefreshService refreshService,
                                                                  SubscriptionRefreshPlanner planner,
-                                                                 PushService pushService) {
+                                                                 PushService pushService,
-            return new SubscriptionRefreshScheduler(subMapper, refreshService, planner, pushService);
+                                                                 RemoteService remoteService) {
+            return new SubscriptionRefreshScheduler(subMapper, refreshService, planner, pushService, remoteService);
         }
     }