Re: [PATCH] Refactoring of LWLock tranches

On Tue, 15 Sep 2015 14:39:51 -0400
Robert Haas <robertmhaas(at)gmail(dot)com> wrote:

> On Tue, Sep 15, 2015 at 12:44 PM, Ildus Kurbangaliev
> <i(dot)kurbangaliev(at)postgrespro(dot)ru> wrote:
> > On Mon, 14 Sep 2015 06:32:22 -0400
> > Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> >
> >> On Sun, Sep 13, 2015 at 5:05 PM, Ildus Kurbangaliev
> >> <i(dot)kurbangaliev(at)postgrespro(dot)ru> wrote:
> >> > Yes, that is because I tried to go with current convention
> >> > working with shmem in Postgres (there are one function that
> >> > returns the size and others that initialize that memory). But I
> >> > like your suggestion about API functions, in that case number of
> >> > tranches and locks will be known during the initialization.
> >>
> >> I also want to leave the door open to tranches that are registered
> >> after initialization. At that point, it's too late to put a
> >> tranche in shared memory, but you can still use DSM.
> >
> > We can hold some extra space in LWLockTrancheArray, add some
> > function for unregistering a tranche, and reuse free items in
> > LWLockTrancheId later.
>
> We could, but since that would be strictly more annoying and less
> flexible than what we've already got, why would we?
>

Yes, probably.
I'm going to change API calls as you suggested earlier.
How you do think the tranches registration after initialization should
look like?

----
Ildus Kurbangaliev
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company