Re: Attach to shared memory after fork()

"=?UTF-8?B?6YKx5a6H6IiqKOeDm+i/nCk=?=" <yuhang(dot)qyh(at)alibaba-inc(dot)com> writes:
> Fork is an expensive operation[1].

Yeah, it's not hugely cheap.

> So I propose to remove shared buffers from postmaster and shmat them
> after fork.

This proposal seems moderately insane. In the first place, it
introduces failure modes we could do without, and in the second place,
how is it not strictly *more* expensive than what happens now? You
still have to end up with all those TLB entries mapped in the child.

(If your kernel is unable to pass down shared-memory TLBs effectively,
ISTM that's a kernel shortcoming not a Postgres architectural problem.)

regards, tom lane