After I run it for few hours and stop traffic i see hundreds of dialogs using fifo command which wont be deleted from memory until I restart. I see dialogs like ..
dialog::  hash=4094:1281471850
        state:: 5
        user_flags:: 0
        timestart:: 0
        timeout:: 0
        callid:: 8abe7f9e-2cd5-1234-84b0-d4ae52bce047
        from_uri:: sip:4117834663@127.0.0.1
        to_uri:: sip:119603452947@127.0.0.1:5060

I saw couple of old posts and tried using "Pp" parameter in create_dialog but it does not seem to be of any effect.

In logs I also see messages like "ERROR:dialog:push_reply_in_dialog: [487] reply in dlg state [2]: missing TAG param in TO hdr" which I am not sure are related to my problem.

John