count(*) …' queries. The reason for this is that

my $nrBuilds = scalar($c->stash->{allBuilds}->search({finished => 1}));

doesn't return an integer, but some magical code reference that when evaluated performs the query and returns an integer. So every use of $nrBuilds in all.tt caused another query. OTOH using …->count causes only one query.

However count(*) still involves a full table scan, so it's still suboptimal.