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 '1994-04-01'
	and o_orderdate < cast(date '1994-04-01' + 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=2300795.60..2300795.65 rows=20 width=176) (actual time=29313.525..29313.530 rows=20 loops=1)
   Buffers: shared hit=1150615 read=220498 written=1
   ->  Sort  (cost=2300795.60..2302237.81 rows=576886 width=176) (actual time=29313.522..29313.526 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=1150615 read=220498 written=1
         ->  HashAggregate  (cost=2279676.01..2285444.87 rows=576886 width=176) (actual time=28984.398..29177.106 rows=379020 loops=1)
               Group Key: customer.c_custkey, customer.c_name, customer.c_acctbal, customer.c_phone, nation.n_name, customer.c_address, customer.c_comment
               Buffers: shared hit=1150612 read=220498 written=1
               ->  Hash Join  (cost=347606.90..2265253.86 rows=576886 width=176) (actual time=6162.673..27096.421 rows=1138104 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=1150612 read=220498 written=1
                     ->  Hash Join  (cost=347605.34..2257320.11 rows=576886 width=154) (actual time=6162.642..26700.485 rows=1138104 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=1150611 read=220498 written=1
                           ->  Hash Join  (cost=278577.34..2179638.82 rows=576886 width=12) (actual time=4826.377..24685.641 rows=1138104 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=1115333 read=220498 written=1
                                 ->  Seq Scan on lineitem  (cost=0.00..1838829.99 rows=15056703 width=12) (actual time=0.055..16906.513 rows=14822649 loops=1)
                                       Filter: (l_returnflag = 'R'::bpchar)
                                       Rows Removed by Filter: 45222648
                                       Buffers: shared hit=858762 read=220498 written=1
                                 ->  Hash  (cost=271300.07..271300.07 rows=582181 width=8) (actual time=4822.975..4822.975 rows=568623 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30404kB
                                       Buffers: shared hit=256571
                                       ->  Bitmap Heap Scan on orders  (cost=6007.36..271300.07 rows=582181 width=8) (actual time=27.637..4655.741 rows=568623 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-04-01'::date) AND (o_orderdate < '1994-07-01'::date))
                                             Rows Removed by Index Recheck: 14446377
                                             Heap Blocks: lossy=256560
                                             Buffers: shared hit=256571
                                             ->  Bitmap Index Scan on orders_o_orderkey_o_orderdate_brin_idx  (cost=0.00..5861.81 rows=582181 width=0) (actual time=27.473..27.473 rows=2566400 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-04-01'::date) AND (o_orderdate < '1994-07-01'::date))
                                                   Buffers: shared hit=11
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1330.104..1330.104 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=35278
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.009..568.725 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.020..0.020 rows=25 loops=1)
                           Buckets: 1024  Batches: 1  Memory Usage: 10kB
                           Buffers: shared hit=1
                           ->  Seq Scan on nation  (cost=0.00..1.25 rows=25 width=30) (actual time=0.005..0.010 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 3.568 ms
 Execution time: 29325.772 ms
(45 rows)

COMMIT;
COMMIT