######## rep_top_student_per_major ########
Sort  (cost=6208.33..6208.56 rows=91 width=95) (actual time=106.513..106.518 rows=6.00 loops=1)
  Sort Key: m.name
  Sort Method: quicksort  Memory: 25kB
  Buffers: shared hit=1056
  CTE standing
    ->  HashAggregate  (cost=5883.79..5943.79 rows=4000 width=56) (actual time=92.287..93.895 rows=4000.00 loops=1)
          Group Key: es.user_id, es.major_id
          Batches: 1  Memory Usage: 1169kB
          Buffers: shared hit=1034
          ->  Hash Left Join  (cost=2140.75..4083.79 rows=80000 width=20) (actual time=16.730..71.128 rows=80000.00 loops=1)
                Hash Cond: (ss.subjects_id = s.id)
                Join Filter: (ps.id IS NOT NULL)
                Rows Removed by Join Filter: 24000
                Buffers: shared hit=1024
                ->  Hash Left Join  (cost=2131.00..3861.07 rows=80000 width=20) (actual time=16.601..57.953 rows=80000.00 loops=1)
                      Hash Cond: (ss.id = ps.enrolled_id)
                      Buffers: shared hit=1021
                      ->  Hash Right Join  (cost=514.00..2034.06 rows=80000 width=16) (actual time=4.275..27.868 rows=80000.00 loops=1)
                            Hash Cond: (ss.enrolled_semesters_id = es.id)
                            Buffers: shared hit=664
                            ->  Seq Scan on semesters_subjects ss  (cost=0.00..1310.00 rows=80000 width=12) (actual time=0.013..5.272 rows=80000.00 loops=1)
                                  Buffers: shared hit=510
                            ->  Hash  (cost=314.00..314.00 rows=16000 width=12) (actual time=4.208..4.209 rows=16000.00 loops=1)
                                  Buckets: 16384  Batches: 1  Memory Usage: 816kB
                                  Buffers: shared hit=154
                                  ->  Seq Scan on enrolled_semesters es  (cost=0.00..314.00 rows=16000 width=12) (actual time=0.020..2.209 rows=16000.00 loops=1)
                                        Buffers: shared hit=154
                      ->  Hash  (cost=917.00..917.00 rows=56000 width=12) (actual time=12.206..12.207 rows=56000.00 loops=1)
                            Buckets: 65536  Batches: 1  Memory Usage: 2919kB
                            Buffers: shared hit=357
                            ->  Seq Scan on passed_subjects ps  (cost=0.00..917.00 rows=56000 width=12) (actual time=0.012..5.719 rows=56000.00 loops=1)
                                  Buffers: shared hit=357
                ->  Hash  (cost=6.00..6.00 rows=300 width=8) (actual time=0.126..0.126 rows=300.00 loops=1)
                      Buckets: 1024  Batches: 1  Memory Usage: 20kB
                      Buffers: shared hit=3
                      ->  Seq Scan on subjects s  (cost=0.00..6.00 rows=300 width=8) (actual time=0.037..0.065 rows=300.00 loops=1)
                            Buffers: shared hit=3
  ->  Nested Loop  (cost=131.42..261.59 rows=91 width=95) (actual time=98.002..106.481 rows=6.00 loops=1)
        Buffers: shared hit=1053
        ->  Hash Anti Join  (cost=131.13..225.46 rows=91 width=60) (actual time=97.975..106.434 rows=6.00 loops=1)
              Hash Cond: (st.major_id = st1.major_id)
              Join Filter: ((st.credits < st1.credits) OR ((st.credits = st1.credits) AND (st.average_grade < st1.average_grade)) OR ((st.credits = st1.credits) AND (st.average_grade = st1.average_grade) AND (st.user_id > st1.user_id)))
              Rows Removed by Join Filter: 28423
              Buffers: shared hit=1035
              ->  Hash Join  (cost=1.14..91.86 rows=120 width=64) (actual time=92.353..93.570 rows=4000.00 loops=1)
                    Hash Cond: (st.major_id = m.id)
                    Buffers: shared hit=1035
                    ->  CTE Scan on standing st  (cost=0.00..80.00 rows=4000 width=56) (actual time=92.293..92.600 rows=4000.00 loops=1)
                          Storage: Memory  Maximum Storage: 251kB
                          Buffers: shared hit=1034
                    ->  Hash  (cost=1.06..1.06 rows=6 width=12) (actual time=0.051..0.051 rows=6.00 loops=1)
                          Buckets: 1024  Batches: 1  Memory Usage: 9kB
                          Buffers: shared hit=1
                          ->  Seq Scan on major m  (cost=0.00..1.06 rows=6 width=12) (actual time=0.045..0.046 rows=6.00 loops=1)
                                Buffers: shared hit=1
              ->  Hash  (cost=80.00..80.00 rows=4000 width=48) (actual time=3.222..3.222 rows=4000.00 loops=1)
                    Buckets: 4096  Batches: 1  Memory Usage: 267kB
                    ->  CTE Scan on standing st1  (cost=0.00..80.00 rows=4000 width=48) (actual time=0.001..2.644 rows=4000.00 loops=1)
                          Storage: Memory  Maximum Storage: 251kB
        ->  Index Scan using users_pkey on users u  (cost=0.28..0.39 rows=1 width=33) (actual time=0.006..0.006 rows=1.00 loops=6)
              Index Cond: (id = st.user_id)
              Index Searches: 6
              Buffers: shared hit=18
Planning:
  Buffers: shared hit=335
Planning Time: 10.504 ms
Execution Time: 107.303 ms
-- OK explain_rep_top_student_per_major.sql