When rendering a tracker report with a table that contains a field that can be aggregated (eg a Selectbox), the aggregate query is always run even when there is no aggregation on the said column.
In trackers with very large number of artifacts (10k+) that can lead up to 50% of the rendering time for nothing. The query is long because it's heavy (all the matching ids are passed around) and more important useless because we already know there won't be any results.