Re: BUG #16831: Idle postgres processes on Linux consumes huge amount of memory

PG Bug reporting form <noreply(at)postgresql(dot)org> writes:
> We are still using postgresql 9.4.1, however, it looks the same issue as in
> 9.5 as someone reported:
> https://www.postgresql.org/account/reset/NzAyMjY-5ng-2bb43dc39c9c2c644a7a/

That link's not too helpful: it leads to a "password reset" form.

> The postgres process consume huge memory as following for the same database
> size
> PID=6840 - Swap used: 145860 KB - (postgres)
> PID=6842 - Swap used: 142564 KB - (postgres)
> PID=6841 - Swap used: 141620 KB - (postgres)

Almost invariably, when we hear reports like this, the true reason
is somebody misunderstanding the numbers they are looking at.
Many Unix tools such as "top" will count the shared memory segment
as memory consumed by each Postgres process, even though in reality
there's only one copy of the shared memory.

I don't know what these "Swap used" numbers are coming out of, but
it'd be wise to check into how the tool accounts for shared memory
before putting much faith in them.

regards, tom lane