Archive for June 19, 2012

MySQL Connect & Oracle OpenWorld 2012

Oracle OpenWorld 2012

Oracle OpenWorld 2012

I’m lucky enough to be involved in a number of sessions across Oracle OpenWorld as well as the (new for this year) MySQL Connect session that precedes it. MySQL Connect runs on Saturday 29th and Sunday 30th September and the Oracle OpenWorld on through Thursday October 4th.

The sessions I’ll be involved with are:

  • MySQL Cluster – From Zero to One Billion in Five Easy Steps: Of course it takes more than five steps to scale to more than one billion queries per minute, but the new configuration features of MySQL Cluster make it much simpler to provision and deploy MySQL Cluster on-premises or in the cloud, automatically optimized for your target use case. This BoF session is designed to give you a demo of the new features, showing how you can use them to quickly build your own proof of concept and then take that into production. The MySQL Cluster Engineering team will be on hand to answer your questions and also listen to the requirements you have for current or future MySQL Cluster projects. This is Birds-of-a-Feather session and is part of the MySQL Connect conference.
  • Developing High-Throughput Services with NoSQL APIs to InnoDB and MySQL Cluster: Ever-increasing performance demands of Web-based services have generated significant interest in providing NoSQL access methods to MySQL (MySQL Cluster from Oracle and the InnoDB storage engine of MySQL), enabling users to maintain all the advantages of their existing relational databases while providing blazing-fast performance for simple queries. Get the best of both worlds: persistence; consistency; rich SQL queries; high availability; scalability; and simple, flexible APIs and schemas for agile development. This session describes the memcached connectors and examines some use cases for how MySQL and memcached fit together in application architectures. It does the same for the newest MySQL Cluster native connector, an easy-to-use, fully asynchronous connector for Node.js. This is a conference session and is part of the MySQL Connect conference.
  • Introduction to MySQL High-Availability Solutions: Databases are the center of today’s Web and enterprise applications, storing and protecting an organization’s most valuable assets and supporting business-critical applications. Just minutes of downtime can result in dissatisfied customers and significant loss of revenue. Ensuring database high availability is therefore a top priority for any organization. Attend this session to learn more about delivering high availability for MySQL-based services. It covers

    • The cause, effect, and impact of downtime
    • A methodology for mapping applications to the right high-availability solution
    • An overview of MySQL high availability, from replication to virtualization, clustering, and multisite redundancy
    • Operational best practices to ensure business continuity

    This is a conference session and is part of Oracle OpenWorld.

Early bird pricing is available for the MySQL Connect until 13th July – same date for Oracle OpenWorld.





MySQL Cluster running on Raspberry Pi

MySQL Cluster running on Raspberry Pi

MySQL Cluster running on Raspberry Pi

I start a long weekend tonight and it’s the kids’ last day of school before their school holidays and so last night felt like the right time to play a bit. This week I received my Raspberry Pi – if you haven’t heard of it then you should take a look at the Raspberry Pi FAQ – basically it’s a ridiculously cheap ($25 or $35 if you want the top of the range model) ARM based PC that’s the size of a credit card.

A knew I had to have one to play with but what to do with it? Why not start by porting MySQL Cluster onto it? We always claim that Cluster runs on commodity hardware – surely this would be the ultimate test of that claim.

I chose the customised version of Debian – you have to copy it onto the SD memory card that acts as the storage for the Pi. Once up and running on the Pi, the first step was to increase the size of the main storage partition – it starts at about 2 Gbytes – using gparted. I then had to compile MySQL Cluster – ARM isn’t a supported platform and so there are no pre-built binaries. I needed to install a couple of packages before I could get very far:

sudo apt-get update
sudo apt-get install cmake
sudo apt-get install libncurses5-dev

Compilation initially got about 80% through before failing and so if you try this yourself then save yourself some time by applying the patch from this bug report before starting. The build scripts wouldn’t work but I was able to just run make…

make
sudo make install

As I knew that memory was tight I tried to come up with a config.ini file that cut down on how much memory would be needed (note that 192.168.1.122 is the Raspberry Pi while 192.168.1.118 is an 8GByte Linux x86-64 PC – doesn’t seem a very fair match!):

[ndb_mgmd]
hostname=192.168.1.122
NodeId=1

[ndbd default]
noofreplicas=2
DataMemory=2M
IndexMemory=1M
DiskPageBufferMemory=4M
StringMemory=5
MaxNoOfConcurrentOperations=1K
MaxNoOfConcurrentTransactions=500
SharedGlobalMemory=500K
LongMessageBuffer=512K
MaxParallelScansPerFragment=16
MaxNoOfAttributes=100
MaxNoOfTables=20
MaxNoOfOrderedIndexes=20

[ndbd]
hostname=192.168.1.122
datadir=/home/pi/mysql/ndb_data
NodeId=3

[ndbd]
hostname=192.168.1.118
datadir=/home/billy/my_cluster/ndbd_data
NodeId=4

[mysqld]
NodeId=50

[mysqld]
NodeId=51

[mysqld]
NodeId=52

[mysqld]
NodeId=53

[mysqld]
NodeId=54

Running the management node worked pretty easily but then I had problems starting the data nodes – checking how much memory I had available gave me a hint as to why!

pi@raspberrypi:~$ free -m
             total       used       free     shared    buffers     cached
Mem:           186         29        157          0          1         11
-/+ buffers/cache:         16        169
Swap:            0          0          0

OK – so 157 Mbytes of memory available and no swap space, not ideal and so the next step was to use gparted again to create swap partitions on the SD card as well a massive 1Gbyte on my MySQL branded USB stick (need to persuade marketing to be a bit more generous with those). A quick edit of /etc/fstab and a restart and things were looking in better shape:

pi@raspberrypi:~$ free -m
             total       used       free     shared    buffers     cached
Mem:           186         29        157          0          1         11
-/+ buffers/cache:         16        169
Swap:         1981          0       1981

Next to start up the management node and 1 data node on the Pi as well as a second data node on the Linux server “ws2” (I want High Availability after all – OK so running the management node on the same host as a data node is a single point of failure)…

pi@raspberrypi:~/mysql$ ndb_mgmd -f conf/config.ini --configdir=/home/pi/mysql/conf/ --initial
pi@raspberrypi:~/mysql$ ndbd
billy@ws2:~$ ndbd -c 192.168.1.122:1186

I could then confirm that everything was up and running:

pi@raspberrypi:~$ ndb_mgm -e show
Connected to Management Server at: localhost:1186
Cluster Configuration
---------------------
[ndbd(NDB)]     2 node(s)
id=3    @192.168.1.122  (mysql-5.5.22 ndb-7.2.6, Nodegroup: 0, Master)
id=4    @192.168.1.118  (mysql-5.5.22 ndb-7.2.6, Nodegroup: 0)

[ndb_mgmd(MGM)] 1 node(s)
id=1    @192.168.1.122  (mysql-5.5.22 ndb-7.2.6)

[mysqld(API)]   5 node(s)
id=50 (not connected, accepting connect from any host)
id=51 (not connected, accepting connect from any host)
id=52 (not connected, accepting connect from any host)
id=53 (not connected, accepting connect from any host)
id=54 (not connected, accepting connect from any host)

Cool!

Next step is to run a MySQL Server so that I can actually test the Cluster – if I tried running that on the Pi then it caused problems (157 Mbytes of RAM doesn’t stretch as far as it used to) – on ws2:

billy@ws2:~/my_cluster$ cat conf/my.cnf
[mysqld]
ndbcluster
datadir=/home/billy/my_cluster/mysqld_data
ndb-connectstring=192.168.1.122:1186

billy@ws2:~/my_cluster$ mysqld --defaults-file=conf/my.cnf&

Check that it really has connected to the Cluster:

pi@raspberrypi:~/mysql$ ndb_mgm -e show
Connected to Management Server at: localhost:1186
Cluster Configuration
---------------------
[ndbd(NDB)]     2 node(s)
id=3    @192.168.1.122  (mysql-5.5.22 ndb-7.2.6, Nodegroup: 0, Master)
id=4    @192.168.1.118  (mysql-5.5.22 ndb-7.2.6, Nodegroup: 0)

[ndb_mgmd(MGM)] 1 node(s)
id=1    @192.168.1.122  (mysql-5.5.22 ndb-7.2.6)

[mysqld(API)]   5 node(s)
id=50   @192.168.1.118  (mysql-5.5.22 ndb-7.2.6)
id=51 (not connected, accepting connect from any host)
id=52 (not connected, accepting connect from any host)
id=53 (not connected, accepting connect from any host)
id=54 (not connected, accepting connect from any host)

Finally, just need to check that I can read and write data…

billy@ws2:~/my_cluster$ mysql -h 127.0.0.1 -P3306 -u root
mysql> CREATE DATABASE clusterdb;USE clusterdb;
Query OK, 1 row affected (0.24 sec)

Database changed
mysql> CREATE TABLE simples (id INT NOT NULL PRIMARY KEY) engine=ndb;
120601 13:30:20 [Note] NDB Binlog: CREATE TABLE Event: REPL$clusterdb/simples
Query OK, 0 rows affected (10.13 sec)

mysql> INSERT INTO simples VALUES (1),(2),(3),(4);
Query OK, 4 rows affected (0.04 sec)
Records: 4  Duplicates: 0  Warnings: 0

mysql> SELECT * FROM simples;
+----+
| id |
+----+
|  1 |
|  2 |
|  4 |
|  3 |
+----+
4 rows in set (0.09 sec)

OK – so is there any real application to this? Well, probably not other than providing a cheap development environment – imagine scaling out to 48 data nodes, that would cost $1,680 (+ the cost of some SD cards)! More practically might be management nodes – we know that they need very few resources. As a reminder – this is not a supported platform!