maria-developers team mailing list archive

[Elena Stepanova <elenst@xxxxxxxxxxxxxxxx>]

Hi,

On 5/9/2013 1:06 PM, Kristian Nielsen wrote:
> "nanyi607rao" <nanyi607rao@xxxxxxxxx> writes:
>
> >   In
> >   http://bazaar.launchpad.net/~maria-captains/maria/10.0-mdev452/revision/3434
> >   you make some change to the class TC_LOG_MMAP,and I want to debug those
> >   codes to see how it works.but i don't understand in what conditions will
> >   MySQL use the TC_LOG_MMAP.it only use TC_LOG_DUMMY or MYSQL_BIN_LOG depends
> >   on the value of opt_bin_log.so how will it use the TC_LOG_MMAP in MySQL.
>
> TC_LOG_MMAP is only used when you have two transactional storage engines (that
> support XA) enabled in the server _and_ the binlog is disabled.
>
> So you need some other transactional engine beside InnoDB. The possibilities I
> know of are TokuDB and PBXT.
>
> If you compile the server with at least two of InnoDB, PBXT, and TokuDB and
> start it with binlog disabled, TC_LOG_MMAP will be used. You then also need to
> do a transaction involving at least two of the engines at the same time.

According to my records, if you choose PBXT as your second engine, 
you'll also need --pbxt-support-xa to hit the code (apparently it's OFF 
by default).

Good luck,
Elena

> As you can imagine, this is not the best tested part of the server ;-). Let us
> know if you discover any problems.
>
>   - Kristian.