worker fetch task num update

escheduler-server/src/main/resources/worker.properties

@@ -5,7 +5,7 @@ worker.exec.threads=100
 worker.heartbeat.interval=10
 
 # submit the number of tasks at a time
-worker.fetch.task.num = 10
+worker.fetch.task.num = 3
 
 
 # only less than cpu avg load, worker server can work. default value : the number of cpu cores * 2