I've read just about everything there is online about improving postgres performance, but the "right" values for SHMMAX and SHMALL still elude me.
The consensus seems to be SHMMAX = total_memory/4 and SHMALL = total_memory/2 are safe starting values.
However, SHMALL can be measured in pages or bytes and I can't find any info about which is used on Ubuntu.
Does Ubuntu (or more generally Debian) use pages or bytes for SHMALL?