Re: BUG #19894: CREATE DATABASE logs all-zeros visibility map

> after CREATE DATABASE on a primary
> select * from pg_visibility_map('pg_class')
> blkno | all_visible | all_frozen
> -------+-------------+------------
> 0 | t | t
> 1 | t | t
> 2 | t | t
> 3 | t | t
> 4 | t | t
> 5 | t | t
> 6 | t | t
> 7 | t | t
> 8 | t | t
> 9 | t | t
> 10 | t | t
> 11 | t | t
> 12 | t | t
> 13 | t | t
> (14 rows)
>
> but on a standby:
> blkno | all_visible | all_frozen
> -------+-------------+------------
> 0 | f | f
> 1 | f | f
> 2 | f | f
> 3 | f | f
> 4 | f | f
> 5 | f | f
> 6 | f | f
> 7 | f | f
> 8 | f | f
> 9 | f | f
> 10 | f | f
> 11 | f | f
> 12 | f | f
> 13 | f | f
> (14 rows)

Why is this a bug?