PostgreSQL 9.4 Index speed very slow on Select - postgresql

Question

The box running PostgreSQL 9.4 is a 32 core system at 3.5ghz per core with 128GB or ram with mirrored Samsung pro 850 SSD drives on FreeBSD with ZFS. This is no reason for this poor of performance from PostgreSQL!
psql (9.4.5)
forex=# \d pair_data;
Table "public.pair_data"
Column | Type | Modifiers
------------+-----------------------------+--------------------------------------------------------
id | integer | not null default nextval('pair_data_id_seq'::regclass)
pair_name | character varying(6) |
pair_price | numeric(9,6) |
ts | timestamp without time zone |
Indexes:
"pair_data_pkey" PRIMARY KEY, btree (id)
"date_idx" gin (ts)
"pair_data_gin_idx1" gin (pair_name)
"pair_data_gin_idx2" gin (ts)
With this select:
forex=# explain (analyze, buffers) select pair_name as name, pair_price as price, ts as date from pair_data where pair_name = 'EURUSD' order by ts desc limit 10;
QUERY PLAN
--------------------------------------------------------------------------------------------------------------------------------------------------------
Limit (cost=201442.55..201442.57 rows=10 width=22) (actual time=10870.395..10870.430 rows=10 loops=1)
Buffers: shared hit=40 read=139150 dirtied=119
-> Sort (cost=201442.55..203787.44 rows=937957 width=22) (actual time=10870.390..10870.401 rows=10 loops=1)
Sort Key: ts
Sort Method: top-N heapsort Memory: 25kB
Buffers: shared hit=40 read=139150 dirtied=119
-> Bitmap Heap Scan on pair_data (cost=9069.17..181173.63 rows=937957 width=22) (actual time=614.976..8903.913 rows=951858 loops=1)
Recheck Cond: ((pair_name)::text = 'EURUSD'::text)
Rows Removed by Index Recheck: 13624055
Heap Blocks: exact=33464 lossy=105456
Buffers: shared hit=40 read=139150 dirtied=119
-> Bitmap Index Scan on pair_data_gin_idx1 (cost=0.00..8834.68 rows=937957 width=0) (actual time=593.701..593.701 rows=951858 loops=1)
Index Cond: ((pair_name)::text = 'EURUSD'::text)
Buffers: shared hit=40 read=230
Planning time: 0.387 ms
Execution time: 10871.419 ms
(16 rows)
Or this select:
forex=# explain (analyze, buffers) with intervals as ( select start, start + interval '4hr' as end from generate_series('2015-12-01 15:00', '2016-01-19 16:00', interval '4hr') as start ) select distinct intervals.start as date, min(pair_price) over w as low, max(pair_price) over w as high, first_value(pair_price) over w as open, last_value(pair_price) over w as close from intervals join pair_data mb on mb.pair_name = 'EURUSD' and mb.ts >= intervals.start and mb.ts < intervals.end window w as (partition by intervals.start order by mb.ts asc rows between unbounded preceding and unbounded following) order by intervals.start;
QUERY PLAN
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Unique (cost=64634864.43..66198331.09 rows=815054 width=23) (actual time=1379732.924..1384602.952 rows=82 loops=1)
Buffers: shared hit=8 read=139210 dirtied=22, temp read=3332596 written=17050
CTE intervals
-> Function Scan on generate_series start (cost=0.00..12.50 rows=1000 width=8) (actual time=0.135..1.801 rows=295 loops=1)
-> Sort (cost=64634851.92..64895429.70 rows=104231111 width=23) (actual time=1379732.918..1381724.179 rows=951970 loops=1)
Sort Key: intervals.start, (min(mb.pair_price) OVER (?)), (max(mb.pair_price) OVER (?)), (first_value(mb.pair_price) OVER (?)), (last_value(mb.pair_price) OVER (?))
Sort Method: external sort Disk: 60808kB
Buffers: shared hit=8 read=139210 dirtied=22, temp read=3332596 written=17050
-> WindowAgg (cost=41474743.35..44341098.90 rows=104231111 width=23) (actual time=1341744.405..1365946.672 rows=951970 loops=1)
Buffers: shared hit=8 read=139210 dirtied=22, temp read=3324995 written=9449
-> Sort (cost=41474743.35..41735321.12 rows=104231111 width=23) (actual time=1341743.502..1343723.884 rows=951970 loops=1)
Sort Key: intervals.start, mb.ts
Sort Method: external sort Disk: 32496kB
Buffers: shared hit=8 read=139210 dirtied=22, temp read=1154778 written=7975
-> Nested Loop (cost=9098.12..21180990.32 rows=104231111 width=23) (actual time=271672.696..1337526.628 rows=951970 loops=1)
Join Filter: ((mb.ts >= intervals.start) AND (mb.ts < intervals."end"))
Rows Removed by Join Filter: 279879180
Buffers: shared hit=8 read=139210 dirtied=22, temp read=1150716 written=3913
-> CTE Scan on intervals (cost=0.00..20.00 rows=1000 width=16) (actual time=0.142..4.075 rows=295 loops=1)
-> Materialize (cost=9098.12..190496.52 rows=938080 width=15) (actual time=2.125..1962.153 rows=951970 loops=295)
Buffers: shared hit=8 read=139210 dirtied=22, temp read=1150716 written=3913
-> Bitmap Heap Scan on pair_data mb (cost=9098.12..181225.12 rows=938080 width=15) (actual time=622.818..11474.987 rows=951970 loops=1)
Recheck Cond: ((pair_name)::text = 'EURUSD'::text)
Rows Removed by Index Recheck: 13623989
Heap Blocks: exact=33485 lossy=105456
Buffers: shared hit=8 read=139210 dirtied=22
-> Bitmap Index Scan on pair_data_gin_idx1 (cost=0.00..8863.60 rows=938080 width=0) (actual time=601.158..601.158 rows=951970 loops=1)
Index Cond: ((pair_name)::text = 'EURUSD'::text)
Buffers: shared hit=8 read=269
Planning time: 0.454 ms
Execution time: 1384653.385 ms
(31 rows)
Table of pair_data only has:
forex=# select count(*) from pair_data;
count
----------
21833886
(1 row)
Why is this doing heap scans when their are indexes? I do not understand what is going on with the query plan? Dose anyone have an idea on where the problem might be?