Assuming a machine with:
* 16 CPU cores
* 64GB RAM
Set to 500 max connections
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
