App_DB not getting updated after deletion in Config_DB

[nverma25]

Hello All,

I found an issue where I see that if I remove a particular member from any table in Config_DB like mtu in PORT_TABLE , then still in Appl_DB's PORT_TABLE that field (mtu) still exists as before. So is this expected as per design? I was expecting that if some field is gone from Config_DB then it will be removed from Appl_DB as well. We have a internal requirement where we are expecting a deletion scenario where User can add some field in any table of config_DB and can remove it also as per his wish. So expectation is same field would be removed from Appl_Db and ASIC_DB as well. We can want to send notification to SAI as well for removal of any such field.

Can someone please explain why the code logic in cfgmgrs or orchagent like this that we can set any field to 0 (assuming some value was set before) but can not remove it completely and expect Appl_DB and Asic_DB to be updated accordingly?