Hi, On 2018-11-21 09:00:58 +1300, Thomas Munro wrote: > On Wed, Nov 21, 2018 at 4:37 AM REIX, Tony <tony.r...@atos.net> wrote: > > YES ! Reading this file, your suggestion should work ! Thx ! > > > > I've rebuilt and run the basic tests. We'll relaunch our tests asap. > > I would be surprised if that makes a difference: > anonymous-mmap-then-fork and SysV shm are just two different ways to > exchange mappings between processes, but I'd expect the virtual memory > object itself to be basically the same, in terms of constraints that > might affect page size at least.
I don't think that's true on many systems, FWIW. On linux there's certainly different behaviour, and e.g. the way to get hugepages for anon-mmap and SysV shmem aren't the same. [1] strongly suggests that that's not the case on FreeBSD either (with sysv shmem being better). I'd attached a patch to implement a GUC to allow users to choose the shmem implementation back then [2]. [1] http://archives.postgresql.org/message-id/2AE143D2-87D3-4AD1-AC78-CE2258230C05%40FreeBSD.org [2] http://archives.postgresql.org/message-id/20140422121921.GD4449%40awork2.anarazel.de Greetings, Andres Freund
