i dont get why you think all memroy will be used. When you say shared_buffers = 16GB effective_cache_size = 48GB
...then this is using only 16GB for shared buffers. The effective _cache_size doesn't cause any memory to.be allocated. It's just a hint to optomizer .... On Wed, 20 Nov 2024, 11:16 Koen De Groote, <kdg....@gmail.com> wrote: > Assuming a machine with: > > * 16 CPU cores > * 64GB RAM > > Set to 500 max connections > > A tool like this: https://pgtune.leopard.in.ua/ > > Will output recommended settings: > > max_connections = 500 > shared_buffers = 16GB > effective_cache_size = 48GB > maintenance_work_mem = 2GB > checkpoint_completion_target = 0.9 > wal_buffers = 16MB > default_statistics_target = 100 > random_page_cost = 1.1 > effective_io_concurrency = 200 > work_mem = 8388kB > huge_pages = try > min_wal_size = 1GB > max_wal_size = 4GB > max_worker_processes = 16 > max_parallel_workers_per_gather = 4 > max_parallel_workers = 16 > max_parallel_maintenance_workers = 4 > > And they basically use up all the memory of the machine. > > 16GB shared buffers, 48GB effective cache size, 8MB of work_mem for some > reason... > > This seems rather extreme. I feel there should be free memory for > emergencies and monitoring solutions. > > And then there's the fact that postgres on this machine will be run in a > docker container. Which, on Linux, receives 64MB of /dev/shm shared memory > by default, but can be increased. > > I feel like I should probably actually lower my upper limit for memory, > regardless of what the machine actually has, so I can have free memory, and > also not bring the container process itself into danger. > > Is it as straightforward as putting my limit on, say 20GB, and then giving > more /dev/shm to the container? Or is there more to consider? > > Regards, > Koen De Groote > > > > > > >
