Re: Suggestions on message transfer among backends

Hello.

At Mon, 11 Mar 2019 21:37:32 +0800, Andy Fan <zhihui.fan1213@gmail.com> wrote in
<CAKU4AWqhZn1v5CR85J74AAVXnTijWTzy6y-3pbYxqmpL5ETEig@mail.gmail.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.fan1213@gmail.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