Re: Bogus temp file reporting?

On Jul 27, 2023, at 11:31 AM, Kyotaro Horiguchi <horikyota.ntt@gmail.com> wrote:

At Thu, 27 Jul 2023 10:30:41 +0300, kg.postgresql@olympiakos.com wrote in 

Hello,

Is there a known issue with temp file reporting?  I have a
production db that is reporting 231TB of temp space usage, which
can’t be true.  temp_blks_written in pg_stat_statements sort of
confirms this, as the reported queries show just a few MB of temp
space usage.  I suspect a reboot will clear this (to do) and wanted
to check with you to see if someone else has had similar
experiences.

Just to clarify, "temprary files" and "temp blocks" refer to different
entities in this context. The "temprary files" are ephemeral storage
that is created and alive only for tasks like tuple sorting, whereas
"temp blocks" are referring to the storage for temprary tables.

If you're performing a massive insert into a temporary table, you'll
find that pg_stat_database.temp_bytes doesn't increase at all.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center