ttl: reschedule scan tasks after update task state (pingcap#39891)

close pingcap#39890

ttl/ttlworker/job_manager.go

@@ -140,9 +140,13 @@ func (m *JobManager) jobLoop() error {
 			}
 			cancel()
 		case <-updateScanTaskStateTicker:
-			m.updateTaskState()
+			if m.updateTaskState() {
+				m.rescheduleJobs(se, now)
+			}
 		case <-m.notifyStateCh:
-			m.updateTaskState()
+			if m.updateTaskState() {
+				m.rescheduleJobs(se, now)
+			}
 		case <-jobCheckTicker:
 			m.checkFinishedJob(se, now)
 			m.checkNotOwnJob()
@@ -212,7 +216,8 @@ func (m *JobManager) resizeWorkers(workers []worker, count int, factory func() w
 	return workers, nil
 }
 
-func (m *JobManager) updateTaskState() {
+// updateTaskState polls the result from scan worker and returns whether there are result polled
+func (m *JobManager) updateTaskState() bool {
 	results := m.pollScanWorkerResults()
 	for _, result := range results {
 		job := findJobWithTableID(m.runningJobs, result.task.tbl.ID)
@@ -223,6 +228,8 @@ func (m *JobManager) updateTaskState() {
 			job.scanTaskErr = multierr.Append(job.scanTaskErr, result.err)
 		}
 	}
+
+	return len(results) > 0
 }
 
 func (m *JobManager) pollScanWorkerResults() []*ttlScanTaskExecResult {