can you post your script? Is it an un-optimized load from QVD due to some transformations or additional functions you use? Usually, an optimized QVD load should work smoothly, as long as you have enough memory available..
I cannot post the script, but I can say that the qvd load is optimized. The problem is that Concatinate operation uses 1 thread only while the server has 16 CPUs. It takes approximately the same time eather for the preprocessed in the same script tables or loaded from QVD.
It's still not clear to me what's happen in your script. However, sometimes load from resident is slower than from QVD. So, it could help to store a processed resident table (esp. when loaded distinct) into QVD and then load again from it, and then concatenate it..
I'm trying to concatenate two large tables. I was trying to do this in several ways:
Both tables are residential
One residential, second loaded from QVD (optimized load)
Both tables are from QVD (optimized load)
The problem is this process is extremely slow because only one CPU thread is enabled, When I join these tables QV is using several cores. It looks like Concatenate operation has the same problem as Group By or Inner Join. So, the question is has anybody mitigated similar issue in some way.