When using different set_system_time within one transaction, no rows are written to the history table.
Example:
=> begin transaction
=*> select set_system_time('2022-01-01');
=*> insert into test (id) values (1);
=*> select set_system_time('2022-01-02');
=*> delete from test where id=1;
=*> select * from test;
(0 rows)
=*> select * from histtest;
(0 rows)
When using different set_system_time within one transaction, no rows are written to the history table. Example: