$c->{irstats2}->{show_archive_only} = 1 results in slow performance of graphs

[mpbraendle]

IRStats2 1.1:
If
$c->{irstats2}->{show_archive_only} = 1;
is enabled in the configuration, the Downloads graph on the summary report takes ages to load (about 10-20 times slower than if disabled).
The problem seems to be caused by an inefficient SQL statement at lib/plugins/EPrints/Plugin/Stats/Handler.pm, line 327.
Wouldn't that be better done already during processing of the statistics?