Tory M Blue <tmblue(at)gmail(dot)com> writes:
> 12 will not start at 10GB, even though it's the same hardware, same config
> file, same physical box, same everything, just version 12 vs 9.5
For me, using all-default settings (in particular, shared_buffers =
128MB), the shared memory block is about 141.6MB using 9.5 and 142.1MB
using 12. So there's half a meg or so of additional data in v12, but
certainly not gigabytes worth.
Are you trying to start both postmasters concurrently? Maybe you're
hitting some kernel limit on the total amount of shared memory in the
system.
regards, tom lane