Query optimization on timestamp and group by in PostgreSQL - postgresql

Question

I want to query for my table with the following structure:
Table "public.company_geo_table"
Column | Type | Collation | Nullable | Default
--------------------+--------+-----------+----------+---------
geoname_id | bigint | | |
date | text | | |
cik | text | | |
count | bigint | | |
country_iso_code | text | | |
subdivision_1_name | text | | |
city_name | text | | |
Indexes:
"cik_country_index" btree (cik, country_iso_code)
"cik_geoname_index" btree (cik, geoname_id)
"cik_index" btree (cik)
"date_index" brin (date)
I tried with the following sql query, which need to query for a specific cik number during a time perid, and group by the cik with geoname_id(different areas).
select cik, geoname_id, sum(count) as total
from company_geo_table
where cik = '1111111'
and date between '2016-01-01' and '2016-01-10'
group by cik, geoname_id
The explanation result showed that they only use the cik index and date index, and did not use the cik_geoname index. Why? Is there any way I can optimize my solution? Any new indices? Thank you in advance.
HashAggregate (cost=117182.79..117521.42 rows=27091 width=47) (actual time=560132.903..560134.229 rows=3552 loops=1)
Group Key: cik, geoname_id
-> Bitmap Heap Scan on company_geo_table (cost=16467.77..116979.48 rows=27108 width=23) (actual time=6486.232..560114.828 rows=8175 loops=1)
Recheck Cond: ((date >= '2016-01-01'::text) AND (date <= '2016-01-10'::text) AND (cik = '1288776'::text))
Rows Removed by Index Recheck: 16621155
Heap Blocks: lossy=193098
-> BitmapAnd (cost=16467.77..16467.77 rows=27428 width=0) (actual time=6469.640..6469.641 rows=0 loops=1)
-> Bitmap Index Scan on date_index (cost=0.00..244.81 rows=7155101 width=0) (actual time=53.034..53.035 rows=8261120 loops=1)
Index Cond: ((date >= '2016-01-01'::text) AND (date <= '2016-01-10'::text))
-> Bitmap Index Scan on cik_index (cost=0.00..16209.15 rows=739278 width=0) (actual time=6370.930..6370.930 rows=676231 loops=1)
Index Cond: (cik = '1111111'::text)
Planning time: 12.909 ms
Execution time: 560135.432 ms

Answer 1

There is not good estimation (and probably the value '1111111' is used too often (I am not sure about impact, but looks so cik column has wrong data type (text), what can be a reason (or partial reason) of not good estimation.
Bitmap Heap Scan on company_geo_table (cost=16467.77..116979.48 rows=27108 width=23) (actual time=6486.232..560114.828 rows=8175 loops=1)
Looks like composite index (date, cik) can helps

Answer 2

Your problem seems to be here:
Rows Removed by Index Recheck: 16621155
Heap Blocks: lossy=193098
Your work_mem setting is too low, so PostgreSQL cannot fit a bitmap that contains one bit per table row, so it degrades to one bit per 8K block. This means that many false positive hits have to be removed during that bitmap heap scan.
Try with higher work_mem and see if that improves query performance.
The ideal index would be
CREATE INDEX ON company_geo_table (cik, date);