Re: Unexplained disk usage in AWS Aurora Postgres

On Tue, Aug 4, 2020 at 4:39 AM Chris Borckholder <
chris(dot)borckholder(at)bitpanda(dot)com> wrote:

> Hi!
>
> We are experiencing a strange situation with an AWS Aurora postgres
> instance.
> The database steadily grows in size, which is expected and normal.
> After enabling logical replication, the disk usage reported by AWS metrics
> increases much faster then the database size (as seen by \l+ in psql). The
> current state is that database size is ~290GB, while AWS reports >640GB
> disk usage.
> We reached out to AWS support of course, which is ultimately responsible.
> Unfortunately they were not able to diagnose this until now.
>
> I checked with the queries from wiki
> https://wiki.postgresql.org/wiki/Disk_Usage , which essentially give the
> same result.
> I tried to check on wal segment file size, but we have no permission to
> execute select pg_ls_waldir().
> The replication slot is active and it also progresses
> (pg_replication_slots.confirmed_flush_lsn increases and is close to
> pg_current_wal_flush_lsn).
>
> Can you imagine other things that I could check from within postgres with
> limited permissions to diagnose this?
>
> Best Regards
> Chris
>
>
If you do archive wal files, maybe the archive_command is failing?