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Re: Codership's Galera patch part of standard MariaDB


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.

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.


Quoting Justin Swanhart <greenlion@xxxxxxxxx>:


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


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