Hi Sergey Ustimenko, congratulations for upgrading from 3.0.0, that version is the first one ever and was very limited

I see nothing wrong in what you report, let me explain: when there are multiple object types in the same inheritance tree, we default to have them share the index. That's totally fine and not a problem even with exclusive_index_use . The reason to default to this behaviour is to optimise performance of polymorphic queries: when searching for "A" we would otherwise need to read from all indexes of the subtypes of A, which is not as efficient as having a single index.

The keyword in those comments is the "non default" index name: if you override the index name for a child, then we allow to separate them.