Re: [PATCH] Refactoring of LWLock tranches

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.

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