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 '1993-11-01'
	and o_orderdate < cast(date '1993-11-01' + 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=1191295.05..1191295.10 rows=20 width=176) (actual time=42151.018..42151.028 rows=20 loops=1)
   Buffers: shared hit=522372 read=911661 dirtied=1067 written=20672
   ->  Sort  (cost=1191295.05..1192717.45 rows=568959 width=176) (actual time=42151.014..42151.018 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=522372 read=911661 dirtied=1067 written=20672
         ->  HashAggregate  (cost=1170465.67..1176155.26 rows=568959 width=176) (actual time=41574.810..41970.424 rows=381299 loops=1)
               Buffers: shared hit=522369 read=911661 dirtied=1067 written=20672
               ->  Hash Join  (cost=400544.33..1156241.69 rows=568959 width=176) (actual time=6352.897..37650.217 rows=1147119 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=522369 read=911661 dirtied=1067 written=20672
                     ->  Hash Join  (cost=400542.77..1148416.94 rows=568959 width=154) (actual time=6352.859..36909.423 rows=1147119 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=522368 read=911661 dirtied=1067 written=20672
                           ->  Merge Join  (cost=331514.77..1068009.76 rows=568959 width=12) (actual time=3075.196..30995.705 rows=1147119 loops=1)
                                 Merge Cond: (orders.o_orderkey = lineitem.l_orderkey)
                                 Buffers: shared hit=522366 read=876385 dirtied=1067 written=17174
                                 ->  Sort  (cost=331514.75..332954.49 rows=575898 width=8) (actual time=3074.935..3273.582 rows=573610 loops=1)
                                       Sort Key: orders.o_orderkey
                                       Sort Method: quicksort  Memory: 51464kB
                                       Buffers: shared hit=229633 read=1980 written=208
                                       ->  Bitmap Heap Scan on orders  (cost=12480.93..276414.40 rows=575898 width=8) (actual time=469.508..2740.395 rows=573610 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                             Buffers: shared hit=229633 read=1980 written=208
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..12336.96 rows=575898 width=0) (actual time=374.346..374.346 rows=578724 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-11-01'::date) AND (o_orderdate < '1994-02-01'::date))
                                                   Buffers: shared hit=107 read=1551 written=136
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.00..690581.44 rows=14937802 width=12) (actual time=0.211..24310.916 rows=14808205 loops=1)
                                       Buffers: shared hit=292733 read=874405 dirtied=1067 written=16966
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=3276.099..3276.099 rows=1500000 loops=1)
                                 Buckets: 262144  Batches: 1  Memory Usage: 265117kB
                                 Buffers: shared hit=2 read=35276 written=3498
                                 ->  Seq Scan on customer  (cost=0.00..50278.00 rows=1500000 width=146) (actual time=0.013..1610.269 rows=1500000 loops=1)
                                       Buffers: shared hit=2 read=35276 written=3498
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.018..0.018 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=0.005..0.009 rows=25 loops=1)
                                 Buffers: shared hit=1
 Total runtime: 42222.593 ms
(40 rows)

COMMIT;
COMMIT