In Dynamics ax we have the ability to enable and disable certain system features that will not be used for with the configurationKeys.
The main difference in ax 2009 to 2012 in this feature is that in ax 2012 the system removes the fields Logicaly while in in 2009 it is a physical removal. This means that a field will keep existing in the system database even as the feature was turned off. So if you turn off for example the Project features in ProjBasic configuration key, the ProjectTable will stay alive in the database while not showing in any query or form throughout the application. In dax 2009, if you do the same, say goodbye to all the records.
It is very important to disable unused configuration keys in the base, as this will result in more demanding situations for the database. If you see thinks like Zakat taxes and Name kana in your database, it probably doesn’t have these keys disabled, and your application is using resources to uselless things such as keeping tabs in a name that should be converted from english or islamic specific tribute. There are scenarios where you need that, but if you don’t, do not keep these keys on, as queries will use more fields, more rendering fields on forms and wasted resources everywhere in the database.
I found in 2012 some specific configurationKeys that actually do remove in a physical way the records, the keys in the sysDeletedObjects. I did a full migration from ax 2009 to 2012 and these specific keys work like in ax 2009 so they delete everything in the database, this is good if you finished your whole migration, because alot of unecessary del_fields will be cleaned and some tables as well.
On a personal note, whenever i start to work in a already used Dax environment be it in development or production, i do check configuration keys, as this is the first health check to see if the parameters in this are well placed, if it have everything turned on, i already judge that many other parameters will be misplaced, as even the most basic was forgoten.
