create table hist1(kod integer,dt date, val integer);
create index ix_hist_1_1 on hist1(dt);
create index ix_hist_1_2 on hist1(kod, dt);
-- vs
create table hist2(kod integer,start_dt date,end_dt date, val integer);
create index ix_hist_2_1 on hist2(start_dt);
create index ix_hist_2_2 on hist2(end_dt);
create index ix_hist_2_3 on hist2(kod, start_dt);
create index ix_hist_2_4 on hist2(kod, end_dt);

-- Прошу прощения, Oracle под рукой нет, могу ошибиться:

insert into hist(kod, dt, val)
 select kod, sysdate-value, kod+value from
 (select level as kod from dual connect by level <= 1000 ) pivot1,
 (select level as value from dual connect by level <= 10000 ) pivot2;

insert into hist(kod, start_dt, end_dt, val)
 select kod, sysdate-value, sysdate-value+ 1 , kod+value from
 (select level as kod from dual connect by level <= 1000 ) pivot1,
 (select level as value from dual connect by level <= 10000 ) pivot2;

-- И от сюда выбрать все актуальные на момент:
SELECT kod, value FROM hist1 t1
  WHERE t1.dt = (SELECT max(t2.dt) FROM hist1 t2
                   WHERE t2.dt < sysdate -  1000  and t2.kod = t1.kod);

SELECT kod, value FROM hist2 t1
  WHERE t1.start_dt < sysdate- 1000  and t1.end_dt >=sysdate- 1000 ;

test1=# select timestamp '-infinity' < now(), timestamp 'infinity' > now(), timestamp 'infinity' > timestamp '-infinity';
 ?column? | ?column? | ?column?
----------+----------+----------
 t        | t        | t
( 1  запись)

test1=# select timestamp '-infinity' + interval '1 day', timestamp '-infinity' - interval '1 day';
 ?column?  | ?column?
-----------+-----------
 -infinity | -infinity
( 1  запись)

test1=# select timestamp 'infinity' + interval '1 day', timestamp 'infinity' - interval '1 day';
 ?column? | ?column?
----------+----------
 infinity | infinity
( 1  запись)

test1=# select timestamp 'infinity' - timestamp '-infinity';
ERROR:  cannot subtract infinite timestamps

test1=# select timestamp 'infinity' - now();
ERROR:  cannot subtract infinite timestamps

test1=# select now() - timestamp 'infinity';
ERROR:  cannot subtract infinite timestamps

test1=# select 'infinity'::float8 > 1e100, '-infinity'::float8 < -1e100, 'infinity'::float8 > 'infinity'::float8  ;
 ?column? | ?column? | ?column?
----------+----------+----------
 t        | t        | t
( 1  запись)

-- С сожалением обнаружил что:
test1=# select  1 /'infinity'::float8;
ERROR:  value out of range: underflow

test1=# select  1 . 0 ::float8 * 'infinity'::float8,  1  + 'infinity'::float8,  1  - 'infinity'::float8,  1  - '-infinity'::float8,  1  + '-infinity'::float8;
 ?column? | ?column? | ?column?  | ?column? | ?column?
----------+----------+-----------+----------+-----------
 Infinity | Infinity | -Infinity | Infinity | -Infinity
( 1  запись)

test1=# select 'infinity'::float8 - 'infinity'::float8, 'infinity'::float8 - '-infinity'::float8, 'infinity'::float8 + '-infinity'::float8;
 ?column? | ?column? | ?column?
----------+----------+----------
      NaN | Infinity |      NaN
( 1  запись)