query1:

'Nested Loop Left Join  (cost=13.22..1022.98 rows=1 width=125) (actual time=3.021..3.024 rows=1 loops=1)'
'  Join Filter: (header_1.header_id = detail_2.header_id)'
'  ->  Nested Loop Left Join  (cost=11.78..1013.93 rows=1 width=89) (actual time=2.978..2.981 rows=1 loops=1)'
'        Join Filter: (header_1.header_id = detail_1.header_id)'
'        ->  Nested Loop  (cost=0.55..4.99 rows=1 width=49) (actual time=0.028..0.030 rows=1 loops=1)'
'              ->  Index Scan using header_pkey on header  (cost=0.28..2.49 rows=1 width=33) (actual time=0.022..0.023 rows=1 loops=1)'
'                    Index Cond: (header_id = 26)'
'              ->  Index Scan using header_pkey on header header_1  (cost=0.28..2.49 rows=1 width=16) (actual time=0.002..0.003 rows=1 loops=1)'
'                    Index Cond: (header_id = 26)'
'        ->  GroupAggregate  (cost=11.23..1008.92 rows=1 width=32) (actual time=2.944..2.945 rows=1 loops=1)'
'              Group Key: detail_1.header_id'
'              ->  Bitmap Heap Scan on detail_1  (cost=11.23..999.21 rows=969 width=32) (actual time=0.301..2.067 rows=1000 loops=1)'
'                    Recheck Cond: (header_id = 26)'
'                    Heap Blocks: exact=1000'
'                    ->  Bitmap Index Scan on idx_detail_1_header_id  (cost=0.00..10.99 rows=969 width=0) (actual time=0.156..0.156 rows=1000 loops=1)'
'                          Index Cond: (header_id = 26)'
'  ->  GroupAggregate  (cost=1.44..9.01 rows=1 width=20) (actual time=0.033..0.033 rows=1 loops=1)'
'        Group Key: detail_2.header_id'
'        ->  Bitmap Heap Scan on detail_2  (cost=1.44..8.95 rows=7 width=20) (actual time=0.013..0.027 rows=7 loops=1)'
'              Recheck Cond: (header_id = 26)'
'              Heap Blocks: exact=7'
'              ->  Bitmap Index Scan on idx_detail_2_header_id  (cost=0.00..1.44 rows=7 width=0) (actual time=0.010..0.010 rows=7 loops=1)'
'                    Index Cond: (header_id = 26)'
'Planning time: 0.420 ms'
'Execution time: 3.127 ms'

query2:

'Hash Right Join  (cost=28367.90..28394.20 rows=3 width=129) (actual time=1245.897..1246.442 rows=2 loops=1)'
'  Hash Cond: (detail_1.header_id = header_1.header_id)'
'  ->  HashAggregate  (cost=28164.00..28176.50 rows=1000 width=32) (actual time=1235.943..1236.304 rows=1000 loops=1)'
'        Group Key: detail_1.header_id'
'        ->  Seq Scan on detail_1  (cost=0.00..18164.00 rows=1000000 width=32) (actual time=0.008..215.064 rows=1000000 loops=1)'
'  ->  Hash  (cost=203.86..203.86 rows=3 width=89) (actual time=9.895..9.895 rows=2 loops=1)'
'        Buckets: 1024  Batches: 1  Memory Usage: 9kB'
'        ->  Hash Right Join  (cost=177.58..203.86 rows=3 width=89) (actual time=8.835..9.891 rows=2 loops=1)'
'              Hash Cond: (detail_2.header_id = header_1.header_id)'
'              ->  HashAggregate  (cost=167.50..180.00 rows=1000 width=20) (actual time=8.743..9.407 rows=1000 loops=1)'
'                    Group Key: detail_2.header_id'
'                    ->  Seq Scan on detail_2  (cost=0.00..115.00 rows=7000 width=20) (actual time=0.008..2.092 rows=7000 loops=1)'
'              ->  Hash  (cost=10.04..10.04 rows=3 width=49) (actual time=0.048..0.048 rows=2 loops=1)'
'                    Buckets: 1024  Batches: 1  Memory Usage: 9kB'
'                    ->  Nested Loop  (cost=0.55..10.04 rows=3 width=49) (actual time=0.029..0.042 rows=2 loops=1)'
'                          ->  Index Scan using header_pkey on header  (cost=0.28..2.53 rows=3 width=33) (actual time=0.017..0.018 rows=2 loops=1)'
'                                Index Cond: ((header_id < 27) AND (header_id > 24))'
'                          ->  Index Scan using header_pkey on header header_1  (cost=0.28..2.49 rows=1 width=16) (actual time=0.005..0.005 rows=1 loops=2)'
'                                Index Cond: (header_id = header.header_id)'
'Planning time: 1.228 ms'
'Execution time: 1246.659 ms'

query3:

'Hash Right Join  (cost=28417.70..28448.72 rows=273 width=129) (actual time=1255.008..1256.036 rows=271 loops=1)'
'  Hash Cond: (detail_1.header_id = header_1.header_id)'
'  ->  HashAggregate  (cost=28164.00..28176.50 rows=1000 width=32) (actual time=1242.275..1242.657 rows=1000 loops=1)'
'        Group Key: detail_1.header_id'
'        ->  Seq Scan on detail_1  (cost=0.00..18164.00 rows=1000000 width=32) (actual time=0.004..209.026 rows=1000000 loops=1)'
'  ->  Hash  (cost=250.28..250.28 rows=273 width=89) (actual time=12.708..12.708 rows=271 loops=1)'
'        Buckets: 1024  Batches: 1  Memory Usage: 38kB'
'        ->  Hash Right Join  (cost=221.30..250.28 rows=273 width=89) (actual time=11.828..12.546 rows=271 loops=1)'
'              Hash Cond: (detail_2.header_id = header_1.header_id)'
'              ->  HashAggregate  (cost=167.50..180.00 rows=1000 width=20) (actual time=9.610..9.958 rows=1000 loops=1)'
'                    Group Key: detail_2.header_id'
'                    ->  Seq Scan on detail_2  (cost=0.00..115.00 rows=7000 width=20) (actual time=0.006..2.440 rows=7000 loops=1)'
'              ->  Hash  (cost=50.39..50.39 rows=273 width=49) (actual time=2.207..2.207 rows=271 loops=1)'
'                    Buckets: 1024  Batches: 1  Memory Usage: 31kB'
'                    ->  Hash Join  (cost=24.91..50.39 rows=273 width=49) (actual time=0.651..1.874 rows=271 loops=1)'
'                          Hash Cond: (header_1.header_id = header.header_id)'
'                          ->  Seq Scan on header header_1  (cost=0.00..19.00 rows=1000 width=16) (actual time=0.008..0.497 rows=1000 loops=1)'
'                          ->  Hash  (cost=21.50..21.50 rows=273 width=33) (actual time=0.609..0.609 rows=271 loops=1)'
'                                Buckets: 1024  Batches: 1  Memory Usage: 26kB'
'                                ->  Seq Scan on header  (cost=0.00..21.50 rows=273 width=33) (actual time=0.009..0.475 rows=271 loops=1)'
'                                      Filter: (description ~~ '%5%'::text)'
'                                      Rows Removed by Filter: 729'
'Planning time: 1.284 ms'
'Execution time: 1256.289 ms'

query4:

'Hash Right Join  (cost=28366.80..28393.10 rows=3 width=96) (actual time=1204.289..1204.851 rows=2 loops=1)'
'  Hash Cond: (detail_1.header_id = header.header_id)'
'  ->  HashAggregate  (cost=28164.00..28176.50 rows=1000 width=32) (actual time=1193.979..1194.338 rows=1000 loops=1)'
'        Group Key: detail_1.header_id'
'        ->  Seq Scan on detail_1  (cost=0.00..18164.00 rows=1000000 width=32) (actual time=0.004..202.247 rows=1000000 loops=1)'
'  ->  Hash  (cost=202.76..202.76 rows=3 width=56) (actual time=10.242..10.242 rows=2 loops=1)'
'        Buckets: 1024  Batches: 1  Memory Usage: 9kB'
'        ->  Hash Right Join  (cost=176.48..202.76 rows=3 width=56) (actual time=9.720..10.238 rows=2 loops=1)'
'              Hash Cond: (detail_2.header_id = header.header_id)'
'              ->  HashAggregate  (cost=167.50..180.00 rows=1000 width=20) (actual time=9.518..9.855 rows=1000 loops=1)'
'                    Group Key: detail_2.header_id'
'                    ->  Seq Scan on detail_2  (cost=0.00..115.00 rows=7000 width=20) (actual time=0.008..2.351 rows=7000 loops=1)'
'              ->  Hash  (cost=8.94..8.94 rows=3 width=16) (actual time=0.141..0.141 rows=2 loops=1)'
'                    Buckets: 1024  Batches: 1  Memory Usage: 9kB'
'                    ->  Nested Loop  (cost=0.55..8.94 rows=3 width=16) (actual time=0.051..0.133 rows=2 loops=1)'
'                          ->  Index Only Scan using header_pkey on header header_1  (cost=0.28..1.44 rows=3 width=4) (actual time=0.034..0.037 rows=2 loops=1)'
'                                Index Cond: ((header_id < 27) AND (header_id > 24))'
'                                Heap Fetches: 0'
'                          ->  Index Scan using header_pkey on header  (cost=0.28..2.49 rows=1 width=16) (actual time=0.008..0.040 rows=1 loops=2)'
'                                Index Cond: (header_id = header_1.header_id)'
'Planning time: 1.223 ms'
'Execution time: 1205.046 ms'