[Buildroot] [PATCH 7/7 v2] mysql: add mariadb galera cluster variant

[Yann E. MORIN <yann.morin.1998@free.fr>]

Thomas, All,

On 2015-08-09 10:46 +0200, Thomas Petazzoni spake thusly:
> On Sun, 9 Aug 2015 01:22:42 +0200, Yann E. MORIN wrote:
> > Well, I never much liked the way the jpeg package has been done.
> > 
> > I do understand that it makes it just work great for users. However,
> > that was not the way virtual packages were supposed to work; it's
> > just a (bad) hack (which in fact predates the actual virtual package
> > infra, IIRC).
> > 
> > And it's a hack that prevents a br2-external from providing its own
> > jpeg implementation (e.g. one optimised to make use of a specific SoC
> > hardware, for example).
> > 
> > Now, the mariadb vs. mysql case might not be so problematic. We don't
> > much expect a myriad of alternate implementations to just pop-up over
> > the night, and even less hardware-specific implementations. But who
> > knows? That's probably what we originally thought about the jpeg case,
> > and now I see at least one reason why we should not have done it that
> > way... Maybe some vendors have specially-crafted mysql /forks/ tailored
> > to specific use-cases (but do we care?)...
> 
> Well, if you take this as an argument, then *all* packages should be
> virtual packages.

Well, certainly not what I said.

> I know a customer that has custom versions of dbus
> and directfb, for example. Should they be virtual packages because of
> that?

"Custom versions" does not count (at least if I understand it has "with
local changes when compared to upstream", in which case they would just
have to use OVERRIDE_SRCDIR for those packages, and manage populating
those overrides externally to Buildroot).

What I am talking about is "alternate implementations", as clearly
illustrated by the GL case. GL is the most prominent example of such
alternate implementations; jpeg should also fall into this category.

Remember we had a case for adding an accelerated jpeg implementation,
specific to the freescale iMX CPUs a while back, for example.

> > So, I'd rather that we just handle virtual packages like is done for the
> > GL case rather than the jpeg case (which I consider broken...)
> 
> Well, for MySQL, I'm still not sure. The main drawback of going all the
> way to the standard virtual package mechanism is that you can no longer
> "select" MySQL from any other package. You can only use a "depends on"
> dependency.

Yes, I agree we have to draw a line somewhere.

I think the mysql vs. mariadb case would fall in the category "we do not
expect alternate implementations to pop up", and thus we can handle it
like is currently done for jpeg.

Regards,
Yann E. MORIN.

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