[Buildbot-devel] About consistency in mysql cluster

Damon Wang damon.devops at gmail.com
Wed Jul 9 13:45:28 UTC 2014

Hi all,

@Dustin has raised a problem about data-ordering problem:

"The issue is a race condition between message passing and database
> replication. Imagine you have a large Buildbot installation with several
> replicated MySQL servers and a redundant RabbitMQ cluster. One buildbot
> master writes changes to a build to the database (an UPDATE operation),
> then sends a message describing the change. On another master, some service
> gets the message and queries a different MySQL server to see the build's
> new status. If the message arrives before the database replication occurs,
> then this master will see stale data. That will lead to a lot of subtle,
> rare bugs. "

The problem in this scene seems a consistency problem in mysql cluster? If
mysql database on every node is strong
consistency, this problem wont appear, right?

But this is more involved with mysql cluster, does anybody know aboout
this? Any helpful materials is welcomed.

I will try to solve it through mq, if you have any idea, please leave a
commit, thanks!

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