ORA-38342: heat map not enabled

I have had the brilliant idea to perform a test to be able to track the modification of database blocks, read and write access in segments made by DMLs and DDLS in one of my databases. I knew already that to do this I had just to enable the parameter heat_map from OFF to ON. So I did : Well, I have done what I thought. Now let’s create a table to check my enabled parameter: What? What happened? Am I crazy? I am 100% sure that I have the…