Re: Do we need a ShmList implementation?

"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> Simon Riggs <simon@2ndQuadrant.com> wrote:
>> My understanding is that we used to have that and it was removed
>> for the reasons Heikki states. There are still vestigial bits
>> still in code.

There's nothing vestigial about SHM_QUEUE --- it's used by the lock
manager.  But it's intended to link together structs whose existence
is managed by somebody else.

>> Not exactly impressed with the SHM_QUEUE stuff though, so I
>> appreciate the sentiment that Kevin expresses.
> So, if I just allocated a fixed memory space to provide an API
> similar to my previous post, does that sound reasonable to you?

I'm not excited about inventing an API with just one use-case; it's
unlikely that you actually end up with anything generally useful.
(SHM_QUEUE seems like a case in point...)  Especially when there are so
many other constraints on what shared memory is usable for.  You might
as well just do this internally to the SERIALIZABLEXACT management code.
        regards, tom lane