Galera MySql Triggers problem

[Karoly Guba]

Hi Everyone!

I work for a company who's data is stored in the mysql database. The company has many apps which connected to the standalone mysql db in the past, and since the number of apps is growing, the mysql db couldn't properly handle the huge load, that is why we decided to use Galera Cluster. 

We have been using Galera for two weeks now and I am glad to have it. It works good, the load is balanced now to tree mysql nodes. 

The only thing what worries me is the database triggers. One part of the app relies on the database triggers. 

My trigger:

CREATE DEFINER=`root`@`%` TRIGGER order_UPDATE_trigger

AFTER UPDATE ON order

FOR EACH ROW

BEGIN

DECLARE id CHAR(20);

DECLARE event varchar(255);

IF (NEW.enabled > 0 OR OLD.enabled > 0)  THEN

SET id=NEW.id;

SET event = concat("DB:","order :", "update :",  id);

INSERT IGNORE INTO order_events set event = event;

END IF;

END

It should trigger an event (put a record into the order_event table whenever the order table has changed).

My experience:

Sometimes (there is no rule when), when I change order table (and enabled field is greater than 0), no event is triggered, then suddenly triggers starts to work properly. 

Is there any specific configuration in Galera to database triggers? Is there any limitations/known issues about triggers in Galera-mysql cluster?

Thanks in advance,

Karoly

[Philip Stoev]

Hello,

Are you using Galera in single-master or multi-master mode?

Philip Stoev

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[Karoly Guba]

Hi Philip!

Thanks for the prompt answer!

To answer your question I use Galera in multi-master mode.

[Philip Stoev]

Hello,

We suspect that what you are observing may be an issue that was discovered
recently and will be fixed in the next Galera Cluster release.

To confirm that this is the case, can you please try to modify your trigger
to not use IGNORE in the INSERT statement? Once you remove the IGNORE
modifier, your application may begin to experience additional deadlock
errors. Those are genuine transaction conflicts that were previously not
reported because of a bug in the handling of the IGNORE modifier.

Thank you.

[Ioannis Venizelos]

Hello,
The bug you named in the handling of the IGNORE modifier, affect the
Server version: 5.5.41 , wsrep version 25.12 ?