XA Transactions and Galera

[Marc Schöchlin]

Hi,

i run a 3 node maraiadb galera cluster (version 10.0.19) and i am wondering why i can set "innodb_support_xa=1".

From my point of view XA transactions are not supported (see https://mariadb.com/kb/en/mariadb/mariadb-galera-cluster-known-limitations/) on galera. 
So what is the reason that i can enable XA transactions?

Is XA partially supported if i interact always with the same node?


Regards
Marc

[Teemu Ollakka]

Hi,

On Monday, June 15, 2015 at 7:37:44 PM UTC+3, Marc Schöchlin wrote:

Hi,

i run a 3 node maraiadb galera cluster (version 10.0.19) and i am wondering why i can set "innodb_support_xa=1".

From my point of view XA transactions are not supported (see https://mariadb.com/kb/en/mariadb/mariadb-galera-cluster-known-limitations/) on galera. 
So what is the reason that i can enable XA transactions?

Parameter innodb_support_xa is used to enable server internal XA (http://dev.mysql.com/doc/refman/5.0/en/innodb-parameters.html#sysvar_innodb_support_xa) and should be enabled if galera is used. 

 

Is XA partially supported if i interact always with the same node?

I would not count on it. Unfortunately the wsrep patch in mysql overrides XA XID and this might break 'external' XA processing.

- Teemu

[Marc Schöchlin]

Hi,

Thanks for your response.

I discovered the following information:
https://dev.mysql.com/doc/refman/5.6/en/xa-restrictions.html
https://www.percona.com/blog/2011/03/02/what-is-innodb_support_xa/


Can you describe the difference between external and internal XA more in detail?
If my XA transaction coordinator is running on a glassfish application server and i want to use XA transactions to handle message queues in combination with database operations this is not possible, right?

Regards
Marc