增加休眠时间，减少冲突

mec-biz/src/main/java/com/ym/mec/biz/service/impl/MusicGroupServiceImpl.java

@@ -300,6 +300,9 @@ public class MusicGroupServiceImpl extends BaseServiceImpl<String, MusicGroup> i
         }
 
         if (chargeInfo.getMaxNum() != null) {
+            if(chargeInfo.getMaxNum() <= chargeInfo.getPaidNum()){
+                throw new BizException("活动人数暂时已满，请稍后再试");
+            }
             chargeInfo.setPaidNum(chargeInfo.getPaidNum() + 1);
             chargeInfo.setUpdateTime(new Date());
             int update = sporadicChargeInfoDao.update(chargeInfo);