For posterity: RDS will definitely allow you to downgrade instance type.
On Wed, Oct 20, 2021 at 1:27 PM Michel SALAIS <msalais@msym.fr> wrote:
Be careful! I am not sure but upgrade for a larger instance can't be temporary. I think you can't downgrade to the original instance class thereafter...
You could always change the size of the RDS instance to something larger than what it currently is running, even just temporarily.
Sent from my iPad
> On Oct 19, 2021, at 6:01 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote: > > Wells Oliver <wells.oliver@gmail.com> writes: >> In an RDS instance with 16GB RAM, I ran a long query which started by >> setting temp_buffers to 16GB, so I think I plum ran out of memory, >> but can anyone point me in a different direction if the following log >> messages indicate something else is awry? > > Yeah, this: > >> 2021-10-19 21:10:37 UTC::@:[24752]:LOG: server process (PID 25813) >> was terminated by signal 9: Killed > > almost certainly indicates the Linux OOM killer at work. If you were > running your own system I'd point you to [1], but I doubt that RDS > lets you put your hands on the relevant knobs. > > regards, tom lane > > [1] > https://www.postgresql.org/docs/current/kernel-resources.html#LINUX-ME > MORY-OVERCOMMIT > >