Magnus Hagander <magnus@xxxxxxxxxxxx> writes: > I wonder how hard it would be to for example expose that through a > commandline switch or tool. Just try to start the server and see if it complains. For instance, with shared_buffers=10000000 I get 2021-06-09 15:08:56.821 EDT [1428121] FATAL: could not map anonymous shared memory: Cannot allocate memory 2021-06-09 15:08:56.821 EDT [1428121] HINT: This error usually means that PostgreSQL's request for a shared memory segment exceeded available memory, swap space, or huge pages. To reduce the request size (currently 83720568832 bytes), reduce PostgreSQL's shared memory usage, perhaps by reducing shared_buffers or max_connections. Of course, if it *does* start, you can do the other thing. Admittedly, we could make that easier somehow; but if it took 25 years for somebody to ask for this, I'm not sure it's worth creating a feature to make it a shade easier. regards, tom lane
