On Thu, May 21, 2020 at 12:59 PM PG Bug reporting form
<noreply@postgresql.org> wrote:
> I am seeing mixed/hybrid Isolation Levels when setting the isolation level
> to SERIALIZABLE READ ONLY DEFERRABLE, this also happens with REPEATABLE READ
> READ ONLY. The user tables sees only the data committed before the
> transaction begins but the system tables sees data committed by other
> transactions after the transaction begins. This means in my example the user
> tables are Serializable Isolation Level and the system tables are Read
> Committed Isolation Level.
That is expected behaviour. Perhaps we're missing a note about it in
the manual?
