busy table performance optimization - postgresql

Question

I have a postgresql table storing data from a table-like form.
id SERIAL,
item_id INTEGER ,
date BIGINT,
column_id INTEGER,
row_id INTEGER,
value TEXT,
some_flags INTEGER,
The issue is we have 5000+ entries per day and the information needs to be kept for years.
So I end up with a huge table witch is busy for the top 1000-5000 rows,
with lots of SELECT, UPDATE, DELETE queries but the old content is rarely used (only in statistics) and is almost never changed.
The question is how can I boost the performance for the daily work (top 5000 entries from 50 millions).
There are simple indexes on almost all columns .. but nothing fancy.
Splitting the table is not possible for now, I`m looking more for Index optimisation .

Answer 1

The advices in the comments from dezso and Jack are good. If you want the simplest then this is how you implement the partial index:
create table t ("date" bigint, archive boolean default false);
insert into t ("date")
select generate_series(
extract(epoch from current_timestamp - interval '5 year')::bigint,
extract(epoch from current_timestamp)::bigint,
5)
;
create index the_date_partial_index on t ("date")
where not archive
;
To avoid having to change all queries adding the index condition rename the table:
alter table t rename to t_table;
And create a view with the old name including the index condition :
create view t as
select *
from t_table
where not archive
;
explain
select *
from t
;
QUERY PLAN
-----------------------------------------------------------------------------------------------
Index Scan using the_date_partial_index on t_table (cost=0.00..385514.41 rows=86559 width=9)
Then each day you archive older rows:
update t_table
set archive = true
where
"date" < extract(epoch from current_timestamp - interval '1 week')
and
not archive
;
The not archive condiditon is to avoid updating millions of already archived rows.