Re: BUG #17974: Walsenders memory usage suddenly spike to 80G+ causing OOM and server reboot

On Wed, Jun 14, 2023 at 08:04:53PM -0400, Michael Guissine wrote:
> On Wed, Jun 14, 2023 at 6:15 PM Andres Freund <andres(at)anarazel(dot)de> wrote:
>>>> Any known issues in pg 14.8 that would trigger this behaviour?
>>>
>>> Yes, there are known issues with memory handling in logical
>>> replication setups. See for example this thread:
>>>
>>> https://www.postgresql.org/message-id/CAMnUB3oYugXCBLSkih+qNsWQPciEwos6g_AMbnz_peNoxfHwyw@mail.gmail.com
>>
>> Why would 14.8 have made that problem worse?

Hmm? I don't necessarily imply that 14.8 made it worse, but that
there are known issues in this area as the other thread mention (which
is mainly about v15, actually, where the situation could be a bit
better).

> This is an assumption obviously, based on the fact that we have been
> running this database for several years already and haven't seen similar
> memory issues until the recent upgrade to 14.8.

Was that all the time with 14 as base? What are the minor versions
you used in the past? Perhaps there is a correlation here that could
help a bit. There have been a few things in this area lately, like
9f2cc1a, 4fbe609, 68dcce2, fd270b7 or 8b9cbd4 (this one made the
decoding cheaper), so it could be possible that a defect has been
introduced. Being able to know the contexts where the memory is
piling up would help a lot, for sure.
--
Michael