Re: PostgreSQL memory usage

On Wed, Oct 16, 2019 at 6:30 PM Alexander Pyhalov <alp@sfedu.ru> wrote:
> I see that at some point several postgresql backends start consuming about 16  GB RAM. If we account for
shared_buffers,it meens 4 GB RAM for private backend memory. How can we achieve such numbers? I don't see any
long-running(or complex) queries (however, there could be long-running transactions and queries to large partitioned
tables).But how could they consume 512* work_mem memory? 

I'm not sure they ae consuming 512 times the work_memory, I mean there
is a whole lot of stuff a process can allocate, and it requires to dig
into the process memory map (something I'm not good at!) to understand
it.
For sure, a single process (backend) can consume one time work_memory
per "complex node" in a query plan, that is it can consume multiple
times the work_memory value if that is available.

Luca