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 '1993-12-01'
	and o_orderdate < cast(date '1993-12-01' + 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=1152041.52..1152041.57 rows=20 width=176) (actual time=19298.220..19298.224 rows=20 loops=1)
   Buffers: shared hit=919548 read=497680 dirtied=114
   ->  Sort  (cost=1152041.52..1153414.11 rows=549036 width=176) (actual time=19298.217..19298.220 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=919548 read=497680 dirtied=114
         ->  HashAggregate  (cost=1131941.51..1137431.87 rows=549036 width=176) (actual time=18986.046..19169.630 rows=374703 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=919545 read=497680 dirtied=114
               ->  Hash Join  (cost=352032.06..1118215.61 rows=549036 width=176) (actual time=3185.872..17332.249 rows=1120171 loops=1)
                     Hash Cond: (customer.c_nationkey = nation.n_nationkey)
                     Buffers: shared hit=919545 read=497680 dirtied=114
                     ->  Hash Join  (cost=352030.50..1110664.80 rows=549036 width=154) (actual time=3185.838..16965.604 rows=1120171 loops=1)
                           Hash Cond: (orders.o_custkey = customer.c_custkey)
                           Buffers: shared hit=919544 read=497680 dirtied=114
                           ->  Hash Join  (cost=283002.50..1033401.26 rows=549036 width=12) (actual time=1892.750..15032.842 rows=1120171 loops=1)
                                 Hash Cond: (lineitem.l_orderkey = orders.o_orderkey)
                                 Buffers: shared hit=884266 read=497680 dirtied=114
                                 ->  Index Scan using lineitem_l_orderkey_idx_l_returnflag on lineitem  (cost=0.43..689056.88 rows=14893854 width=12) (actual time=0.077..10086.449 rows=14807964 loops=1)
                                       Buffers: shared hit=717542 read=434086 dirtied=114
                                 ->  Hash  (cost=276028.02..276028.02 rows=557924 width=8) (actual time=1889.214..1889.214 rows=560419 loops=1)
                                       Buckets: 1048576  Batches: 1  Memory Usage: 30084kB
                                       Buffers: shared hit=166724 read=63594
                                       ->  Bitmap Heap Scan on orders  (cost=12111.16..276028.02 rows=557924 width=8) (actual time=196.737..1726.187 rows=560419 loops=1)
                                             Recheck Cond: ((o_orderdate >= '1993-12-01'::date) AND (o_orderdate < '1994-03-01'::date))
                                             Heap Blocks: exact=228700
                                             Buffers: shared hit=166724 read=63594
                                             ->  Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx  (cost=0.00..11971.67 rows=557924 width=0) (actual time=134.758..134.758 rows=565493 loops=1)
                                                   Index Cond: ((o_orderdate >= '1993-12-01'::date) AND (o_orderdate < '1994-03-01'::date))
                                                   Buffers: shared read=1618
                           ->  Hash  (cost=50278.00..50278.00 rows=1500000 width=146) (actual time=1286.532..1286.532 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..554.413 rows=1500000 loops=1)
                                       Buffers: shared hit=35278
                     ->  Hash  (cost=1.25..1.25 rows=25 width=30) (actual time=0.019..0.019 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..0.009 rows=25 loops=1)
                                 Buffers: shared hit=1
 Planning time: 3.565 ms
 Execution time: 19309.138 ms
(42 rows)

COMMIT;
COMMIT