Re: Writing WAL files

Hello Robert

On 2020-Oct-04, Robert Inder wrote:

> One of the things I like about the old PGSQL 9 setup is that it generates
> and ships a WAL file every few minutes, even if nothing has happened in the
> database.
> I find it re-assuring to be able to see WAL files arriving and being
> processed without problem even when the live system was idle.
>
> But I cannot get PGSQL 12 to do this. It only writes (and thus ships) WAL
> files when something happens in the database.
> If the database is idle, it simply does not write any WAL files.

This is on purpose; archiving WAL files that contain nothing is pure
wastage of good electrons. I suggest that in PG12 you can monitor the
"lag" of a standby server more directly by looking at columns write_lag,
flush_lag, replay_lag in the pg_stat_replication view. (You'll need to
change your configuration so that it uses streaming replication instead
of pg_standby and rsync, but that's far more convenient so it's a good
change anyway.)