From: Sergei Golubchik
Date: October 11 2012 7:54pm
Subject: Re: XA problems in mysql-5.6.7-rc
List-Archive: http://lists.mysql.com/internals/38608
Message-Id: <20121011195457.GB22057@meddwl.fritz.box>
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Hi, Rich!

On Oct 11, Rich Prohaska wrote:
> Hello All,
> 
> TokuDB supports XA and runs in both MariaDB and MySQL.  It works in
> MariaDB without any patches.  Unfortunately, there are several XA bugs
> related to multiple XA storage engines in MySQL 5.6.7.  It would be
> great if these bugs were fixed in MySQL.  One way to test these
> changes is to include another example storage engine that supports XA.
>  This storage engine does not even need to work; it just needs to
> export the prepare method in the handlerton interface.
> 
> There is a block of code in handler.cc surrounded by
> WILL_BE_DELETED_LATER.  If I disable the debug assert, what else do I
> need to worry about?

There is a possible deadlock in the MySQL XA code. I don't know how
probable it is to get it in practice, we've found it with our mutex
deadlock detector (MariaDB only). I had to rework XA code in MariaDB
quite a bit to get rid of the deadlock.

Regards,
Sergei