You can find lots of problems just with sysbench. The issue is limited to simple queries - anything with a short response time. There is work in progress to fix some of this in 5.6 and 5.7. But I have not revisited the bugs lately. Regardless, I think this is an opportunity where MariaDB can distinguish itself. Alas, given my narrow perspective I have no idea whether that is a big deal to others.

* http://mysqlha.blogspot.com/2013/09/mysql-41-forever.html

* http://mysqlha.blogspot.com/2013/09/single-threaded-connect-performance.html
* http://mysqlha.blogspot.com/2013/09/mysql-572-single-threaded-performance.html

* http://mysqlha.blogspot.com/2013/05/mysql-56-single-threaded-performance.html

* http://mysqlha.blogspot.com/2013/05/mysql-56-versus-40-for-read-only.html

* http://mysqlha.blogspot.com/2013/04/mysql-56-single-thread-update-only.html

* http://mysqlha.blogspot.com/2013/03/mysql-56-single-threaded-read-only.html

On Fri, Nov 22, 2013 at 12:46 PM, Kristian Nielsen <knielsen@knielsen-hq.org> wrote:

MARK CALLAGHAN <mdcallag@gmail.com> writes:

> Resources are finite, but it would be great if MariaDB also did something
> about single-thread performance regressions. MySQL has not done/said much

Do you have some pointers about where to start with this? I am thinking about
which types of queries / benchmarks to check and improve on. I know you did
some work on investigating these regressions already, which is sure to be
useful.

- Kristian.

--
Mark Callaghan
mdcallag@gmail.com