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 '1994-10-01'
	and o_orderdate < cast(date '1994-10-01' + 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=1147099.75..1147099.80 rows=20 width=176) (actual time=24971.896..24971.903 rows=20 loops=1)
   Buffers: shared hit=445989 read=963174
   ->  Sort  (cost=1147099.75..1148517.46 rows=567084 width=176) (actual time=24971.891..24971.895 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=445989 read=963174
         ->  HashAggregate  (cost=1126339.01..1132009.85 rows=567084 width=176) (actual time=24370.903..24818.988 rows=382158 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=445986 read=963174
               ->  Hash Join  (cost=350592.20..1112161.91 rows=567084 width=176) (actual time=4606.269..22467.383 rows=1151430 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=445986 read=963174
                     ->  Hash Join  (cost=350590.64..1104362.94 rows=567084 width=154) (actual time=4606.225..22102.829 rows=1151430 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=445985 read=963174
                           ->  Hash Join  (cost=281562.64..1026828.68 rows=567084 width=12) (actual time=2947.351..19431.683 rows=1151430 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=445983 read=927898
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..684129.84 rows=14790880 width=12) (actual time=0.076..11386.728 rows=14822992 loops=1)
                                       Buffers: shared hit=371174 read=772574
                                 ->  Hash  (cost=274366.25..274366.25 rows=575676 width=8) (actual time=2937.915..2937.915 rows=574973 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30652kB
                                       Buffers: shared hit=74809 read=155324
                                       ->  Bitmap Heap Scan on orders  (cost=12209.11..274366.25 rows=575676 width=8) (actual time=244.971..2675.042 rows=574973 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1994-10-01'::date) AND (o_orderdate < '1995-01-01'::date))
                                             Heap Blocks: exact=228561
                                             Buffers: shared hit=74809 read=155324
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12065.19 rows=575676 width=0) (actual time=161.001..161.001 rows=574973 loops=1)
                                                   Index Cond: ((o_orderdate >= '1994-10-01'::date) AND (o_orderdate < '1995-01-01'::date))
                                                   Buffers: shared read=1572
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1646.852..1646.852 rows=1500000 loops=1)
                                 Buckets: 2097152  Batches: 1  Memory Usage: 281501kB
                                 Buffers: shared hit=2 read=35276
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.006..723.225 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.029..0.029 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=0.009..0.013 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 6.679 ms
 Execution time: 24985.929 ms
(42 rows)

COMMIT;
COMMIT