Re: Postgres Out Of Memory Crash

On Thu, 2023-11-02 at 09:12 +0000, Avi Weinberg wrote:
> I'm using Patroni Postgres installation and noticed that twice already postgres
> crashed due to out of memory.  I'm using logical replication with around 30-40
> active subscribers on this machine.  The machine has 128GB but only 32GB is allocated
> to Postgres.  How can I know what is actually causing the out of memory issue?
> Is it caused by not optimal postgres configuration or something else?

You should look into the PostgreSQL log.  That should show a message like

  LOG:  server process (PID 16024) was terminated by signal 9: Killed
  DETAIL:  Failed process was running: SELECT ...

It is not certain, but often that statement is the one that used up
all that memory.  At least it is a starting point for your investigation.

Yours,
Laurenz Albe