For 1. and the

group_sid

part the solution is either to remove

index

or implement the optimizations. For 2. and 1, (

gid

) I don't know, which is why I was asking about the extended schema For 3. I don't know now the solution, but it's just an additional reason for me to have a way to specify columns that are really platform specific (not present in the schema of the non matching platform)