BEGIN; BEGIN EXPLAIN (ANALYZE, BUFFERS) select n_name, sum(l_extendedprice * (1 - l_discount)) as revenue from customer, orders, lineitem, supplier, nation, region where c_custkey = o_custkey and l_orderkey = o_orderkey and l_suppkey = s_suppkey and c_nationkey = s_nationkey and s_nationkey = n_nationkey and n_regionkey = r_regionkey and r_name = 'AFRICA' and o_orderdate >= date '1995-01-01' and o_orderdate < date '1995-01-01' + interval '1 year' group by n_name order by revenue desc; QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Sort (cost=2425113.35..2425113.41 rows=25 width=34) (actual time=163906.242..163906.242 rows=5 loops=1) Sort Key: (sum((lineitem.l_extendedprice * (1::double precision - lineitem.l_discount)))) Sort Method: quicksort Memory: 25kB Buffers: shared hit=941440 read=534775 written=438 -> HashAggregate (cost=2425112.52..2425112.77 rows=25 width=34) (actual time=163906.054..163906.061 rows=5 loops=1) Buffers: shared hit=941437 read=534775 written=438 -> Hash Join (cost=399034.46..2424381.56 rows=73096 width=34) (actual time=30169.232..163548.815 rows=72207 loops=1) Hash Cond: ((lineitem.l_suppkey = supplier.s_suppkey) AND (customer.c_nationkey = supplier.s_nationkey)) Buffers: shared hit=941437 read=534775 written=438 -> Hash Join (cost=394355.46..2382417.40 rows=1827710 width=46) (actual time=29934.736..158142.452 rows=1820053 loops=1) Hash Cond: (lineitem.l_orderkey = orders.o_orderkey) Buffers: shared hit=939977 read=534053 written=438 -> Seq Scan on lineitem (cost=0.00..1669157.88 rows=60125388 width=16) (actual time=0.037..71327.944 rows=59985552 loops=1) Buffers: shared hit=540912 read=526992 written=4 -> Hash (cost=388644.38..388644.38 rows=456886 width=38) (actual time=29934.076..29934.076 rows=454913 loops=1) Buckets: 65536 Batches: 1 Memory Usage: 31987kB Buffers: shared hit=399065 read=7061 written=434 -> Hash Join (cost=87467.50..388644.38 rows=456886 width=38) (actual time=8476.470..29078.911 rows=454913 loops=1) Hash Cond: (orders.o_custkey = customer.c_custkey) Buffers: shared hit=399065 read=7061 written=434 -> Bitmap Heap Scan on orders (cost=48425.28..336466.70 rows=2284428 width=8) (actual time=2784.376..14971.982 rows=2275582 loops=1) Recheck Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate < '1996-01-01 00:00:00'::timestamp without time zone)) Buffers: shared hit=253741 read=6235 written=420 -> Bitmap Index Scan on orders_o_orderdate_o_orderkey_idx (cost=0.00..47854.18 rows=2284428 width=0) (actual time=2636.593..2636.593 rows=2280135 loops=1) Index Cond: ((o_orderdate >= '1995-01-01'::date) AND (o_orderdate < '1996-01-01 00:00:00'::timestamp without time zone)) Buffers: shared read=6221 written=420 -> Hash (cost=35292.22..35292.22 rows=300000 width=38) (actual time=5691.738..5691.738 rows=299493 loops=1) Buckets: 32768 Batches: 1 Memory Usage: 21059kB Buffers: shared hit=145324 read=826 written=14 -> Nested Loop (cost=905.09..35292.22 rows=300000 width=38) (actual time=54.846..5224.148 rows=299493 loops=1) Buffers: shared hit=145324 read=826 written=14 -> Nested Loop (cost=0.00..14.07 rows=5 width=30) (actual time=0.062..0.210 rows=5 loops=1) Join Filter: (nation.n_regionkey = region.r_regionkey) Rows Removed by Join Filter: 20 Buffers: shared hit=3 -> Index Scan using pk_nation on nation (cost=0.00..12.63 rows=25 width=34) (actual time=0.016..0.075 rows=25 loops=1) Buffers: shared hit=2 -> Materialize (cost=0.00..1.07 rows=1 width=4) (actual time=0.002..0.003 rows=1 loops=25) Buffers: shared hit=1 -> Seq Scan on region (cost=0.00..1.06 rows=1 width=4) (actual time=0.027..0.035 rows=1 loops=1) Filter: (r_name = 'AFRICA'::bpchar) Rows Removed by Filter: 4 Buffers: shared hit=1 -> Bitmap Heap Scan on customer (cost=905.09..6455.63 rows=60000 width=8) (actual time=52.139..1017.142 rows=59899 loops=5) Recheck Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=145321 read=826 written=14 -> Bitmap Index Scan on customer_c_nationkey_c_custkey_idx (cost=0.00..890.09 rows=60000 width=0) (actual time=41.818..41.818 rows=59899 loops=5) Index Cond: (c_nationkey = nation.n_nationkey) Buffers: shared hit=7 read=826 written=14 -> Hash (cost=3179.00..3179.00 rows=100000 width=8) (actual time=227.918..227.918 rows=100000 loops=1) Buckets: 16384 Batches: 1 Memory Usage: 3907kB Buffers: shared hit=1457 read=722 -> Seq Scan on supplier (cost=0.00..3179.00 rows=100000 width=8) (actual time=0.010..178.587 rows=100000 loops=1) Buffers: shared hit=1457 read=722 Total runtime: 163933.065 ms (55 rows) COMMIT; COMMIT