Usage of "_as_of ()"

[lucasaccarola]

Hi there,

using postgresql-11-periods/focal-pgdg,now 1.2-1.pgdg20.04+2 amd64

I've defined a table with system versioning as follow:

create table test1 (
  id serial primary key,
  status varchar (30) default 'on'
);
select periods.add_system_time_period ('test1', 'row_start', 'row_end');
select periods.add_system_versioning ('test1');

I've then add some rows to my table via:

insert into test1 (status) values ('on');
insert into test1 (status) values ('off');
insert into test1 (status) values ('on');

Now I'm trying to get my value at given date via test1__as_of ():

ls=# SELECT * FROM test1__as_of (now ());
 id | status |           row_start           | row_end             
----+--------+-------------------------------+----------
  1 | on     | 2020-10-21 19:37:07.567824+02 | infinity
  2 | off    | 2020-10-21 19:52:33.665405+02 | infinity
  3 | on     | 2020-10-21 19:53:44.834846+02 | infinity
(3 rows)

ls=# SELECT * FROM test1__as_of ('2020-10-21 19:52:35.665405+02');
 id | status |           row_start           | row_end             
----+--------+-------------------------------+----------
  1 | on    | 2020-10-21 19:37:07.567824+02 | infinity
  2 | off   | 2020-10-21 19:52:33.665405+02 | infinity
(2 rows)

ls=# SELECT * FROM test1__as_of ('2020-10-21 19:40:07.567824+02');
 id | status |           row_start           | row_end             
----+--------+-------------------------------+----------
  1 | on     | 2020-10-21 19:37:07.567824+02 | infinity
(1 row)

The question is: why I'm gotting all the records instead of a single one containing my status value at given date ?
Am I missing something ?

Best.