On 02/11/2014 09:00 AM, seppo.jaakola@codership.com 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 :

...

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 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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Thanks Sergei, that sounds great! I'll keep an eye on that issue Honza On 02/12/2014 05:37 PM, Sergei Golubchik wrote:

Hi, Honza!

On Feb 11, Honza Horak 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?

Yes, possible. Yes, we are considering this. MDEV-5665

The main part of this task is to ensure that this will have no effect of the server whatsoever when galera is disabled.

Regards, Sergei