Re: Suggestions on message transfer among backends

Hello.

At Mon, 11 Mar 2019 21:37:32 +0800, Andy Fan <zhihui(dot)fan1213(at)gmail(dot)com> wrote in <CAKU4AWqhZn1v5CR85J74AAVXnTijWTzy6y-3pbYxqmpL5ETEig(at)mail(dot)gmail(dot)com>
> notes on the shared hash map: it needs multi writers and multi readers.
>
> On Mon, Mar 11, 2019 at 9:36 PM Andy Fan <zhihui(dot)fan1213(at)gmail(dot)com> wrote:
>
> > Hi:
> > I need some function which requires some message exchange among
> > different back-ends （connections).
> > specially I need a shared hash map and a message queue.
> >
> > Message queue: it should be many writers, 1 reader. Looks POSIX
> > message queue should be OK, but postgre doesn't use it. is there any
> > equivalent in PG?
> >
> > shared hash map: the number of items can be fixed and the value can be
> > fixed as well.
> >
> > any keywords or explanation will be extremely helpful.

I suppose that you are writing an extension or tweaking the core
code in C source. dshash (dynamic shared hash) would work for you
as shared hash map, and is shm_mq usable as the message queue?

--
Kyotaro Horiguchi
NTT Open Source Software Center