Re: BUG #16503: excessive memory consumption.

PG Bug reporting form <noreply@postgresql.org> writes:
> Thu, 18 Jun 2020 14:41:13 GMT    The database process was killed by the OS due
> to excessive memory consumption. It is recommended to tune your database
> workload and/or parameter usage to reduce memory consumption.

This looks like you got hit by the dreaded OOM killer.  See

https://www.postgresql.org/docs/current/kernel-resources.html#LINUX-MEMORY-OVERCOMMIT

for some background and advice.

            regards, tom lane