maria-developers team mailing list archive

[Kristian Nielsen <knielsen@xxxxxxxxxxxxxxx>]

"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.

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

 - Kristian.