Hi, Aleksey!
On Dec 18, Aleksey Midenkov wrote:
> On Wed, Dec 18, 2019 at 7:23 PM Sergei Golubchik <serg@mariadb.org> wrote:
> > On Dec 18, Aleksey Midenkov wrote:
> > > On Wed, Dec 18, 2019 at 1:11 PM Sergei Golubchik <serg@mariadb.org> wrote:
> > > >
> > > > On Dec 18, Aleksey Midenkov wrote:
> > > > >
> > > > > We better go away from this C service layer of thd_*()
> > > > > functions between server and plugins and use class methods
> > > > > instead.
> > > >
> > > > Why is it better? Isn't it just the syntax sugar?
> > >
> > > Having local class interfaces is easier to maintain. Additional
> > > API layer is development costs overhead.
> >
> > That's neglectable, thd_make_lex_string() needs next to no
> > maintainance.
>
> Particularly to this function I don't like its name, semantics and
> signature.
As far as the service is concerned, "don't like" is too weak an
argument, changing a service comes with a compatibility cost.
Of course, if there is compatibility issue. That's not the case for our in-tree plugins, I guess?
But for the internal server use we can change thd->make_lex_string(),
indeed.
> They are over-complicated considering its frequent use. I could
> justify such function if it was used rarely, but when you have 8 calls
> of it subsequently -- it is ugly. And it takes time to check the
> signature because it is not clear what is NULL and what is TRUE. I
> mean you periodically have to check it and this is multiplied by
> infinite future, so yes, it takes time.
Yes, it could've been better, I agree. But see above.
> Now, to the THD::make_clex_string() and THD::make_lex_string(). These
> methods should not be in THD at all. Its monolithic design with
> million of different methods looks to me as a huge mess accumulated
> across long time. There was no need to create proxies when there
> would not be such a large class in the first place.
They could be methods of a MEM_ROOT. One shouldn't need a complete THD
to allocate memory from a memroot.
I believe, that's not much better than THD method. THD, MEM_ROOT are generic classes, they should know nothing about classes they provide services for.
Regards,
Sergei
VP of MariaDB Server Engineering
and security@mariadb.org