last I have meant sort of indices.
There are different types of metrics for example where I needed multiply real types. I clustered them in a perf-* index (mentioned as type 1)
The real logs also have different types because each application has different types. Since all are tuxedo applications I clustered them in a tux-* index (mentioned as type 2).
So my concern is putting ,merging index of type 1 into type 2 index, if it gets slower if I query only for a (real) type which was formerly in index type 1.
hope it is now clearer what I meant 
thanks a lot