The new Facets implementation from #255 includes several hard-coded settings which should be made configurable somehow:

Number of rows to return in a facet (maybe this should also be an option that can be set via quersytring argument, e.g. ?_facet=qSpecies:40):

Time limit for executing a facet:

Maximum unique values returned in order for a column to be suggested as a facet:

Time limit for calculating if a column should be a suggested facet: