execution time ~ 15sec.

NOTICE:  QUERY PLAN:

Subquery Scan progress_report  (cost=14648.65..14648.65 rows=4 width=128)
  ->  Sort  (cost=14648.65..14648.65 rows=4 width=128)
        ->  Merge Join  (cost=14644.00..14648.62 rows=4 width=128)
              ->  Sort  (cost=11.02..11.02 rows=2 width=48)
                    ->  Seq Scan on activity  (cost=0.00..11.00 rows=2 width=48)
              ->  Sort  (cost=14632.99..14632.99 rows=367 width=112)
                    ->  Subquery Scan media_acts  (cost=14553.17..14617.36 rows=367 width=112)
                          ->  Aggregate  (cost=14553.17..14617.36 rows=367 width=112)
                                ->  Group  (cost=14553.17..14562.34 rows=3668 width=112)
                                      ->  Sort  (cost=14553.17..14553.17 rows=3668 width=112)
                                            ->  Subquery Scan stats  (cost=13969.18..14336.00 rows=3668 width=112)
                                                  ->  Unique  (cost=13969.18..14336.00 rows=3668 width=112)
                                                        ->  Sort  (cost=13969.18..13969.18 rows=36682 width=112)
                                                              ->  Append  (cost=1.31..9744.33 rows=36682 width=112)
                                                                    ->  Subquery Scan *SELECT* 1  (cost=1.31..1154.05 rows=11459 width=56)
                                                                          ->  Hash Join  (cost=1.31..1154.05 rows=11459 width=56)
                                                                                ->  Seq Scan on media  (cost=0.00..407.59 rows=11459 width=36)
                                                                                ->  Hash  (cost=1.25..1.25 rows=25 width=20)
                                                                                      ->  Seq Scan on mediatypemap  (cost=0.00..1.25 rows=25 width=20)
                                                                    ->  Subquery Scan *SELECT* 2  (cost=1313.31..4930.60 rows=20704 width=80)
                                                                          ->  Hash Join  (cost=1313.31..4930.60 rows=20704 width=80)
                                                                                ->  Hash Join  (cost=1283.70..3513.64 rows=21196 width=64)
                                                                                      ->  Seq Scan on intsetmedia  (cost=0.00..399.96 rows=21196 width=16)
                                                                                      ->  Hash  (cost=1154.05..1154.05 rows=11459 width=48)
                                                                                            ->  Hash Join  (cost=1.31..1154.05 rows=11459 width=48)
                                                                                                  ->  Seq Scan on media  (cost=0.00..407.59 rows=11459 width=28)
                                                                                                  ->  Hash  (cost=1.25..1.25 rows=25 width=20)
                                                                                                        ->  Seq Scan on mediatypemap  (cost=0.00..1.25 rows=25 width=20)
                                                                                ->  Hash  (cost=27.69..27.69 rows=769 width=16)
                                                                                      ->  Seq Scan on set  (cost=0.00..27.69 rows=769 width=16)
                                                                    ->  Subquery Scan *SELECT* 3  (cost=1469.06..3659.68 rows=4519 width=112)
                                                                          ->  Hash Join  (cost=1469.06..3659.68 rows=4519 width=112)
                                                                                ->  Hash Join  (cost=1467.74..3364.32 rows=4519 width=92)
                                                                                      ->  Hash Join  (cost=689.81..1978.41 rows=4519 width=64)
                                                                                            ->  Hash Join  (cost=585.40..1498.78 rows=9148 width=32)
                                                                                                  ->  Seq Scan on dtrowmedia  (cost=0.00..164.48 rows=9148 width=16)
                                                                                                  ->  Hash  (cost=306.99..306.99 rows=16799 width=16)
                                                                                                        ->  Seq Scan on dtrow  (cost=0.00..306.99 rows=16799 width=16)
                                                                                            ->  Hash  (cost=102.55..102.55 rows=744 width=32)
                                                                                                  ->  Hash Join  (cost=6.62..102.55 rows=744 width=32)
                                                                                                        ->  Seq Scan on dtcol  (cost=0.00..32.06 rows=1506 width=16)
                                                                                                        ->  Hash  (cost=5.90..5.90 rows=290 width=16)
                                                                                                              ->  Seq Scan on datatable  (cost=0.00..5.90 rows=290 width=16)
                                                                                      ->  Hash  (cost=407.59..407.59 rows=11459 width=28)
                                                                                            ->  Seq Scan on media  (cost=0.00..407.59 rows=11459 width=28)
                                                                                ->  Hash  (cost=1.25..1.25 rows=25 width=20)
                                                                                      ->  Seq Scan on mediatypemap  (cost=0.00..1.25 rows=25 width=20)

EXPLAIN