Postgresql query is very slow for my big table

My database version is postgresql 9.5. create table if not exists request_log ( id bigserial not null constraint app_requests_pkey primary key, request_date timestamp not null, ip varchar(50), start_time timestamp, application_name varchar(200), request_path text, display_url text, username varchar(50) ); I have a table that icludes incoming http request informations. The id column is primary key and index. The table has no relation. So I have 72320081 rows in this table. And when I run the count query to get count of table, select count(id) from request_log; query takes 3-5 minutes. The explain(analyze, buffers, format text) result for this request is: Aggregate (cost=3447214.71..3447214.72 rows=1 width=0) (actual time=135575.947..135575.947 rows=1 loops=1) Buffers: shared hit=96 read=2551303 -> Seq Scan on request_log (cost=0.00..3268051.57 rows=71665257 width=0) (actual time=2.517..129032.408 rows=72320081 loops=1) Buffers: shared hit=96 read=2551303 Planning time: 0.067 ms Execution time: 135575.988 ms This is very bad performance for me. I could not get reports from table from web applications because of performance. My server hardware sources are: - OS: Linux ubuntu server 16, On Vmware - 4 core cpu - Mem 6Gb - HDD 120 Gb I run the queries at nights, that there are no users on database, but slow. How can solve this problem?