Speed up admin front page.

* Don't show a categories summary unless asked via a link
* Don't needlessly join in questionnaire/update summaries
* Switch count(distinct()) to a subselect as it turns out
  select count(*) from (select distinct(user_id) from problem) temp;
  is a lot quicker than select count(distinct(user_id)) from problem;

1 files changed, 4 insertions, 1 deletions

diff --git a/perllib/FixMyStreet/DB/ResultSet/Problem.pm b/perllib/FixMyStreet/DB/ResultSet/Problem.pm
index 40076d374..e9f5d0f8e 100644
--- a/perllib/FixMyStreet/DB/ResultSet/Problem.pm
+++ b/perllib/FixMyStreet/DB/ResultSet/Problem.pm
@@ -210,7 +210,10 @@ sub unique_users {
     return $rs->search( {
         state => [ FixMyStreet::DB::Result::Problem->visible_states() ],
     }, {
-        select => [ { count => { distinct => 'user_id' } } ],
+        select => [ { distinct => 'user_id' } ],
+        as     => [ 'user_id' ]
+    } )->as_subselect_rs->search( undef, {
+        select => [ { count => 'user_id' } ],
         as     => [ 'count' ]
     } )->first->get_column('count');
 }