At the moment, the default setting for internalQueryFrameworkControl is "trySbe", which means that the system will use SBE for all eligible queries and fallback to the classic engine otherwise. We also support "forceClassicEngine", in which case all queries use the Classic Engine. (There are other settings for this parameter related to the Bonsai optimizer which are irrelevant for this discussion.)

The goal for this ticket is to introduce a third setting for the internalQueryFrameworkControl parameter which causes the system to behave more like it did in version 6.0 – an "in between" option in which queries which can benefit from pushdown of $group or $lookup stages use SBE and all other queries use Classic.