Re: [PATCH v12] GSSAPI encryption support

On Wed, Apr 6, 2016 at 5:58 AM, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> wrote:
> Robbie Harwood wrote:
>> Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> writes:
>> > It seems to me that the right solution for this is to create a new
>> > memory context which is a direct child of TopMemoryContext, so that
>> > palloc can be used, and so that it can be reset separately, and that it
>> > doesn't suffer from resets of other contexts. (I think Michael's point
>> > is that if those chunks were it a context of their own, you wouldn't
>> > need the pfrees but a MemCxtReset would be enough.)
>>
>> Hmm, that's also an option. I read Michael's point as arguing for
>> calloc()/free() rather than a new context, but I could be wrong.
>
> Yeah, if you weren't using stringinfos that would be an option, but
> since you are I think that's out of the question.

To be honest, my first thought about that was to create a private
memory context only dedicated to those buffers, save it in pg_gssinfo
and remove those pfree calls as the memory context would clean up
itself with inheritance. Regarding the calloc/free stuff, should I be
a committer I would have given it a spin to see how the code gets
uglier or better and would have done a final decision depending on
that (you are true about the repalloc/pfree calls in memory contexts
btw, I forgot that).

>> A question, though: it it valuable for the context to be reset()able
>> separately? If there were more than just these two buffers going into
>> it, I could see it being convenient - especially if it were for
>> different encryption types, for instance - but it seems like it would be
>> overkill?
>
> If two buffers is all, I think retail pfrees are fine. I haven't
> actually read the patch.

Those are the only two buffers present per session.
--
Michael