Re: [HACKERS] Why must -N be >= 16?

The Hermit Hacker <scrappy(at)hub(dot)org> writes:
> Just trying to start up a 'mini-process' of -B 8 -N 4, and it tells me
> that -N must be >= 16 ... why?

You misread it --- -N can be as small as you like, but we don't allow
a really tiny -B. To quote the code:

if (NBuffers < 2 * MaxBackends || NBuffers < 16)
{
/* Do not accept -B so small that backends are likely to starve for
* lack of buffers. The specific choices here are somewhat arbitrary.
*/
fprintf(stderr, "%s: -B must be at least twice -N and at least 16.\n",
progname);
exit(1);
}

I'm not even real sure that -B 16 is going to work well if you throw
complex queries at it --- we've not stressed the system with small
numbers of buffers.

regards, tom lane