BEGIN;
BEGIN
EXPLAIN (ANALYZE, BUFFERS)
select
	c_custkey,
	c_name,
	sum(l_extendedprice * (1 - l_discount)) as revenue,
	c_acctbal,
	n_name,
	c_address,
	c_phone,
	c_comment
from
	customer,
	orders,
	lineitem,
	nation
where
	c_custkey = o_custkey
	and l_orderkey = o_orderkey
	and o_orderdate >= date '1994-06-01'
	and o_orderdate < cast(date '1994-06-01' + interval '3 month' as date)
	and l_returnflag = 'R'
	and c_nationkey = n_nationkey
group by
	c_custkey,
	c_name,
	c_acctbal,
	c_phone,
	n_name,
	c_address,
	c_comment
order by
	revenue desc
LIMIT 20;
                                                                                                QUERY PLAN                                                                                                 
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 Limit  (cost=1193085.71..1193085.76 rows=20 width=175) (actual time=65106.477..65106.483 rows=20 loops=1)
   Buffers: shared hit=863650 read=566441 written=92
   ->  Sort  (cost=1193085.71..1194503.85 rows=567253 width=175) (actual time=65106.472..65106.476 rows=20 loops=1)
         Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount))))
         Sort Method: top-N heapsort  Memory: 30kB
         Buffers: shared hit=863650 read=566441 written=92
         ->  HashAggregate  (cost=1172318.79..1177991.32 rows=567253 width=175) (actual time=64561.218..64940.600 rows=381999 loops=1)
               Buffers: shared hit=863647 read=566441 written=92
               ->  Hash Join  (cost=402436.43..1158137.46 rows=567253 width=175) (actual time=14126.517..60495.581 rows=1149543 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=863647 read=566441 written=92
                     ->  Hash Join  (cost=402434.87..1150336.17 rows=567253 width=153) (actual time=14126.442..59624.866 rows=1149543 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=863646 read=566441 written=92
                           ->  Merge Join  (cost=333406.87..1069963.11 rows=567253 width=12) (actual time=9063.289..51566.050 rows=1149543 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=863644 read=531165 written=92
                                 ->  Sort  (cost=333406.85..334852.80 rows=578380 width=8) (actual time=9062.734..9274.125 rows=574654 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51513kB
                                       Buffers: shared hit=141393 read=91520
                                       ->  Bitmap Heap Scan on orders  (cost=12562.39..278051.09 rows=578380 width=8) (actual time=617.565..8726.163 rows=574654 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-06-01'::date) AND (o_orderdate < '1994-09-01'::date))
                                             Buffers: shared hit=141393 read=91520
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12417.79 rows=578380 width=0) (actual time=486.435..486.435 rows=582260 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-06-01'::date) AND (o_orderdate < '1994-09-01'::date))
                                                   Buffers: shared hit=2 read=1665
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..690698.60 rows=14917296 width=12) (actual time=0.522..38541.970 rows=14822448 loops=1)
                                       Buffers: shared hit=722251 read=439645 written=92
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=145) (actual time=5060.734..5060.734 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=2 read=35276
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=145) (actual time=0.024..3154.952 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.047..0.047 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 2kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.029..0.036 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 65184.982 ms
(40 rows)

COMMIT;
COMMIT