[BUG] Instance health DB sync scheduler can stop after one persistence error #6496

Current Behavior

InstanceCheckService protects the heartbeat state-check task from exceptions, but the periodic DB sync task is scheduled directly with no exception guard.

executor.scheduleWithFixedDelay(this::scheduled, 30, scheduledTime, TimeUnit.SECONDS);
executor.scheduleWithFixedDelay(this::syncDB, 40, scheduledTime, TimeUnit.SECONDS);

scheduled() catches and logs exceptions, but syncDB() does not:

public void syncDB() {
    instanceHealthBeatInfo.values().forEach(vo -> {
        instanceInfoService.createOrUpdate(vo);
    });
}

If instanceInfoService.createOrUpdate(...) throws once, for example due to a transient database error, the exception escapes the scheduled task. ScheduledThreadPoolExecutor then suppresses subsequent executions of that fixed-delay task.

Expected Behavior

A DB sync failure should be logged and retried in the next scheduled run, rather than stopping all future instance-state persistence.

Impact

After a transient persistence error, in-memory instance health can continue changing while DB state is no longer updated until the admin process restarts.

Code Location

• shenyu-admin/src/main/java/org/apache/shenyu/admin/service/impl/InstanceCheckService.java
  • setup() schedules syncDB directly.
  • syncDB() has no exception handling around persistence.