Thursday, October 02, 2008

dbt2-0.37.37 uploaded and various other stuff

There was a small bug in the dbt2-0.37.36 version I uploaded which
I have now fixed in the new dbt2-0.37.37 version.

There has also been some interesting benchmark tests done where
we have run DBT2 on a T5220 box (Niagara II chips). We can show
the scalable performance benefits here as well. We've been able
to run with 20 data nodes on 1 box (these boxes can run up to
64 threads at a time) with scalable performance increase from
4 nodes.

We had a developer meeting a few weeks ago and there were lots of
activities. Personally I had most fun seeing the demo of
Parallel ALTER TABLE. We loaded a table with 10 million 70-80 byte
rows. We had access to a machine with 64 GB of memory and
16 cores. It was very interesting to run one SQL command and
see the load in top of mysqld go to 1600%. Altering a 10 million
row table in 2.5 seconds I thought was pretty good.

Another cool demo was to see the online add node in MySQL Cluster.
This is an interesting feature which I started thinking about
in 1999, had a first design then, changed to a second variant
in 2001 and changed again around 2005 and the final version that
was implemented was the fourth version of the design. The nice
thing is that the fourth version actually contains some nice
innovations that neither of the earlier designs had. So cooking
an idea for a long time can be really beneficial some times.
For a very brief description of this work see Jonas Oreland's

Jonas and Pekka is also working on another cool optimisation
of MySQL Cluster where the data node will become multithreaded.
There will be up to 6 threads in the first released version of
this. Jonas measured in a test today that one could do 370.000
inserts per second on 1 8-core box with this feature (and this
is still a fairly unstable version where there are still some
performance issues remaining). We're getting close to measuring
computer speed in MDO (MegaDatabaseOperations per second)
instead of in MHz.

Jonas and myself is also working on removing from MySQL Cluster
"the single transporter mutex" which will improve the scalability
of MySQL Servers using MySQL Cluster. We're working on this in
parallel using the same basic design but with small variations
on the details. Will be interesting to see which variant that
works best.

Finally Frazer has optimised the handling of large records in
the data node to the extent that inserts of 5k records gets
twice the speed. The interesting thing is that the benchmark
for this hits the limit of Gigabit Ethernet already with 1
CPU working at 80% which is quite interesting.

So as you can see there is a lot of interesting things cooking
at MySQL and then I haven't even mentioned the work we're
doing together with other Sun folks on optimising MySQL. More
on that later.

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