??????[Feature][process_definition] process definition need to support parallel or serial choose. and parallel mode support wait queue length

[yongqing]

why I add two cloums in table t_ds_process_definition:
1??in process,need to solve serial run and serial run command can set wait 
queue length.
2??after later??we need to statistics serial commands for every 
projet or every processdef. 
 
this function has uesd in our company.  I hope can merger this function to 
apache??and in future our company can use more new apache release version??


------------------ ???????? ------------------
??????:                                                                         
                                               "yongqing"                       
                                                             
<597365...@qq.com&gt;;
????????:&nbsp;2020??9??12??(??????) ????5:34
??????:&nbsp;"dev"<dev@dolphinscheduler.apache.org&gt;;

????:&nbsp;[Feature][process_definition] process definition need to support 
parallel or serial choose. and parallel mode support wait queue length



hi,all
our company need this funcation. so we add this funcation into apache. and our 
company ??s all old tasks will be switched to incubator-dolphinscheduler system.

process definition need to support parallel or serial choose.
if is serial in dispatch??need to the previous process_instance execute 
complete??next process_instance can to run??

?????????????????????????????? 
????????????????????????????????????????????????????????????????????????????
??????????????????????????????????????????????????????????????????????????.

&nbsp;in database, table t_ds_process_definition need add 
cloum:is_parallel,serial_command_lengh. sql script need to exec in database.
alter table t_ds_process_definition add is_parallel tinyint default '1' comment 
'0:serial,1:parallel';
alter table t_ds_process_definition add serial_command_lengh bigint default '0' 
comment 'serial exec command lengh';