We can assume that columns are already renamed if we have already renamed all columns of all dataTables in a map.
This saves 50-200ms when aggregating records (eg when range date is requested) per record. Depending on the dataTables can save even way more time or a bit less.
I just did some profiling on the demo database where the performance benefit is > 1 second (out of 26 seconds total time)
FYI: I just had a case where this saves like 60 seconds (out of 360 seconds total time)