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Re: Codership's Galera patch part of standard MariaDB

 

On 02/11/2014 09:00 AM, seppo.jaakola@xxxxxxxxxxxxx wrote:
Hi, I'll add $.02 more to this discussion.

Galera does not use the MySQL Pluggable Storage Engine Aarchitecture
(PSEA), because Galera needs, as pointed out by Justin, more interaction
with other storage engines (InnoDB currently, TokuDB in future) and
MySQL server, than what is provided by PSEA.

So the patches in the server code add a new API that offers more than PSEA offers, right?

But nevertheless, Galera is still a plugin. MySQL wsrep patch implements
a different plugin framework, which allows replication plugins, like
Galera, to be loaded and taken is use in MySQL server. Galera plugin can
be enabled and disabled by configuration (wsrep_provider=
<pointer-to-plugin-library> | none). When disabled, the server should
work as vanilla MySQL | MariaDB server, with no feature nor performance
impact.

Really? I actually understood that it was not possible to disable it this way, so this really makes me confused now. Maybe the Galera/wresp plugin/patch is too ambiguous, so just to confirm I understand it correctly now: It is totally OK to use the MariaDB server with necessary enhancements (patches in the code) but without wresp/Galera plugin installed and use it without any feature nor performance impact, right?

Thanks for the respond,
Honza


-seppo

Quoting Justin Swanhart <greenlion@xxxxxxxxx>:

Hi,

As I understand it, Galera doesn't work through the pluggable storage
engine API, so adding it via the engine interface is not an option.  It
intercepts the binary log capture process, implements a global
transaction
identifier and wire transaction state prototocol (wsrep), and is tightly
integrated with InnoDB so as to trigger deadlocks on incoming replication
write conflicts.  It is not possible to use Galera with TokuDB or MyISAM
for this reason (though MyISAM is technically supported, it is not a good
idea).  Because it only works with InnoDB and MyISAM (barely), it makes
sense (at least to me) to make it a separate package.

Just my $.02


On Mon, Feb 10, 2014 at 11:11 PM, Honza Horak <hhorak@xxxxxxxxxx> wrote:

Hi guys,

my Google-foo is poor today and I can't find any discussion about
"inclusion of Codership's Galera patch to standard code-source of
MariaDB".
I'd like to see that one could just use the wresp plugin and have a
working
Galera cluster (even if that would mean to introduce new engine) without
having another instance of the package.

Is that technically possible at all and if so, are there any thoughts
like
this?

Thanks,
Honza

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http://www.codership.com  seppo.jaakola@xxxxxxxxxxxxx
tel: +358 40 510 5938 skype: seppo_jaakola



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