MySQL Cluster 8.0 tutorial

MySQL Cluster Engineering
January 31, 2020
Frazer Clement
MySQL Ndb 8.0 Cluster tutorial

2 © 2020 Oracle
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Safe harbor statement

3 © 2020 Oracle
You can follow the steps on your own machine, using a VirtualBox VM for simplicity
You will need to install VirtualBox and the NdbVM virtual machine.
●
There are USB sticks available with :
●
[VirtualBox install binaries for Windows, Mac OS X, Linux generic]
●
VM appliance (NdbVM.ova) for importing NdbVM into VirtualBox
●
~4GB RAM, ~ x GB disk space
Steps :
1) Copy files from USB stick onto your machine
2) Install VirtualBox
3) Import VM appliance into VirtualBox to create a VM (wait...)
4) Start the VM
How to follow the tutorial on your machine

4 © 2020 Oracle
Introduction
MySQL Ndb Cluster 8.0
Installation
Configuration
Starting a cluster
Exploring the cluster
High Availability
Backup and Restore
Joins, Foreign Keys, JSON
NdbInfo views
Synchronized Privileges
Addnode and Rebalance data
MySQL Ndb Cluster 8.0 tutorial
MGMD
NDBD
NDBD
NDBD
NDBD
NDBD
NDBD
MY MY MY
Some (sub)sections are optional and
can be skipped as necessary

5 © 2020 Oracle
●
Learn about MySQL Ndb Cluster 8.0
●
See MySQL Cluster 8.0 setup and running
●
See some of the features of MySQL Cluster
●
Setup and use your own MySQL Cluster
Introduction : Goals

6 © 2020 Oracle
●
Discussion, Slides, Demonstration
●
Follow along on your own machine in a virtual machine
●
VM contains a text file with instructions :
/home/ndb/cluster_tutorial.txt
●
Instructions can be followed, commands pasted in, example output
compared with your own
●
Some sections can be skipped
Introduction : Tutorial format

7 © 2020 Oracle
5.1   Kill one data node
========================
For this tutorial, all data node processes are running in the same
VM, but we can identify them by their nodeid= suffix.
We can use this suffix to kill both the Angel and Worker processes
around the same time using the pkill command.
Shell >

ps ef | grep ndbmtd
pkill f nodeid=1
ps ef | grep ndbmtd

    Example output :
      ndb@ndbVirtualBox:~$ ps ef | grep ndbmtd
      ndb       3033     1  0 18:41 ?        00:00:01 ndbmtd –ndbnodeid=1
      ...
Introduction : /home/ndb/cluster_tutorial.txt

8 © 2020 Oracle
MySQL Ndb Cluster
MySQL (Ndb) Cluster is used in critical applications where the highest availability and
highest write scalability with low stable latency and efficiency are required :
- Telecoms core networks
- Massive online games
- Stock exchange trade analysis
- Web site session stores
- Single sign-on and authentication use cases
- …
MySQL Cluster is backed by Oracle, with Oracle Support contracts available
MySQL Cluster is mature, proven and dependable.
MySQL Cluster is fully documented open source.
https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster.html

9 © 2020 Oracle
MySQL Ndb Cluster
MySQL (Ndb) Cluster is a distributed, highly available and scalable version of MySQL
MySQL Cluster allows MySQL Server instances to access and operate on data stored in a
separate set of servers known as Data nodes.
Data nodes provide a highly available and scalable transactional query and data service to a
number of MySQL Servers, or other clients.
NDBD
NDBD
MY
NDBD
NDBD
MY
NDBD
NDBD
MY
NDBD
NDBD
MY
NDBD
NDBD
MY
NDBD
NDBD
MY
NDBD
NDBD
MY
NDBD
NDBD
MYSQL
DATA

10 © 2020 Oracle
MySQL Ndb Cluster concepts : Distributed system
- MySQL Cluster is a shared nothing system - processes on different machines communicate
with each other to form a cluster of nodes
- Data nodes collaborate to store tables and indexes, and
implement constraints, transactions, joins, backup, checkpointing
and other high availability features
- Data and indexes are automatically partitioned (sharded) across
Nodegroups
- All data is query-able, modifiable and consistent at all times
- Row locking and two phase commit is used within and between
Nodegroups
- Data nodes have a native (NoSQL) interface called NdbApi, accessible
from C++, Java, ...
- MySQLD nodes provide a SQL interface and the MySQL async replication interface
(Binlogs), implemented using NdbApi, alongside all the usual MySQL functionality
NDBD
NDBD
MY
NDBD
NDBD
MY

11 © 2020 Oracle
MySQL Ndb Cluster concepts : Replicas and Scaling
- Up to 4 data nodes (NDBD) replicate their data synchronously within a NodeGroup for high
availability and read scaling.
- A cluster can scale out online by adding nodegroups, increasing the total resources
available and scaling write throughput
- A cluster can scale out SQL capacity and redundancy online by adding MySQLD or other
clients
NDBD
NDBD
NDBD
NDBD
1-4 replicas
NDBD
NDBD
NDBD
NDBD
NDBD
NDBD
NDBD
NDBD
MY MY MY
Scale out Nodegroups Scale out MySQL Servers

12 © 2020 Oracle
MySQL Ndb Cluster concepts : Online operations
MySQL Cluster supports online operations for high availability - queries and writing
transactions experience minimal disturbance during :
- Schema changes
- Add column
- Add index / Drop index
- Operations
- Backup
- Software upgrade
- Hardware upgrade
- Scale out nodegroups
- Scale out MySQLDs
- Incidents
- Node failure
- Node recovery
99.9999%

13 © 2020 Oracle
MySQL Ndb Cluster concepts : MySQL Server
Ndb storage engine implementation
Handler / Storage Engine Api
SQL parsing, optimisation, execution
Client threads
NdbApi
Network communication with data nodes
MySQL clients MySQL clients MySQL clients
Generic
MySQL
Server code
Generic NdbApi
code
Glue
SQL
Handler Api calls
NdbApi calls
'Protocol 6'

14 © 2020 Oracle
MySQL Ndb Cluster concepts : Data node
Replication thread
Main thread
LDM threads
TC threads
Send threads
Request
processing
threads
TC and LDM threads
do most work, must
be well fed by Send +
Receive threads
Receive threads IO threads
Connect threads Watchdog

15 © 2020 Oracle
MySQL Ndb Cluster 8.0
MySQL Cluster is a distributed, highly available, scalable version of MySQL
MySQL Cluster 8.0 combines the latest version of MySQL Server 8.0 with an enhanced
MySQL Cluster storage engine
MySQL Cluster storage engine enhancements in 8.0 :
- Row sizes up to 30kB
- Improved automatic configuration and resource sharing
- Enhanced backup parallelism
- Enhanced join pushdown parallelism
- Enhanced disk I/O
- Up to 144 data nodes in a cluster
- 2, 3 or 4 way synchronous replication within a NodeGroup
MySQL Cluster 8.0.19 Generally Available January 13, 2020
MySQL Cluster 8.0 continues to evolve...
8.0.19

16 © 2020 Oracle
Introduction √
MySQL Ndb Cluster 8.0 √
Installation
Configuration
Starting a cluster
High Availability
Backup and Restore
NdbInfo views
Installation
- MySQL Cluster installation options
- Tutorial installation steps

17 © 2020 Oracle
Installation
MySQL Cluster 8.0 can be deployed on Linux, Solaris (x86 + SPARC), Mac OS and Windows
There are multiple ways to install MySQL Cluster 8.0 including :
- Using packages from Oracle for your OS
- Using packages from your OS distributor
- Using Docker container images from Oracle
- Using generic binaries from Oracle
- Manually
- Compiling from source
Other options, for different scenarios :
- Using MySQL Cluster Manager (MCM), or Mysql Cluster Installer
- Using dbDeployer or other tools
https://dev.mysql.com/doc/refman/8.0/en/mysql-cluster-installation.html

18 © 2020 Oracle
Tutorial installation
For this tutorial we will run MySQL Cluster 8.0 in an VirtualBox VM containing :
- A ‘minimal’ Ubuntu 18.04 ‘Desktop’ installation
- MySQL Cluster 8.0.19 (Community GPL) installed from Debian packages
Using a VM like this allows the tutorial to be followed on various operating systems in an
isolated and repeatable way without OS specific distractions or interactions with existing
installed software.
The VM is available as a VirtualBox ‘appliance’ file (NdbVM.ova) which can be imported into
VirtualBox to create a VM on your machine.
First step : Copy all the files from the USB stick onto your machine

19 © 2020 Oracle
Tutorial Installation : Install VirtualBox
The USB stick contains install binaries for VirtualBox
6.1.2 for Windows, Mac OSX and generic Linux and
a short README about installation (and removal) in
tutorial/VirtualBox/README.
Alternatively VirtualBox can be downloaded from :
https://www.virtualbox.org/wiki/Downloads
Full documentation on how to install is available here :
https://www.virtualbox.org/manual/UserManual.html
Second step : Install VirtualBox onto your machine (if you do not already have it)

20 © 2020 Oracle
Tutorial Installation : Import NdbVM.ova appliance
Third step : Import the NdbVM.ova appliance to create the NdbVM virtual machine
1. Open the VirtualBox VM Manager
2. Select the File → Import Appliance menu option
3. Select the NdbVM.ova file you copied
4. On the Appliance Settings dialog, ensure that the appliance is configured with 4GB of
(virtual) RAM
5. Click Import and Wait for it to complete
…

21 © 2020 Oracle
Tutorial Installation : Start the NdbVM VM
Once the Import has completed, select the
NdbVM instance and click the Start icon.
The VM will boot, and eventually auto-login to a
desktop.
The VM is created with a user called ndb, with
password ndbcluster and home directory
/home/ndb
The desktop contains a link to the
cluster_tutorial.txt file

22 © 2020 Oracle
Tutorial Installation : Using the NdbVM VM
The terminal icon can be used to open a terminal
running the bash shell.
The bash shell prompt shows the current directory.
The terminal supports multiple tabs (File→New Tab).
There are a number of editors installed including :
- nano
- vi ( Exit vi with ESC :!q or ESC :!wq )
- gedit
You can see that MySQL Cluster 8.0.19 is installed
by running > mysql --version

23 © 2020 Oracle
Tutorial Installation : Reading the tutorial instructions
The tutorial instructions are available in a text
file in /home/ndb, also linked from the desktop.
Double clicking on the icon opens the instructions
in gedit, from where they can easily be read,
copied + pasted etc.
The terminal and editor icons on the left of the
Desktop (or ALT - TAB) can be used to swap
between applications.

24 © 2020 Oracle
Tutorial Installation
In this tutorial we discuss a number of binaries installed as part of MySQL Cluster 8.0
ndb_mgmd Management Server
ndbmtd Data node
mysqld MySQL Server
ndb_mgm Management client shell
mysql MySQL client shell
mysqlbinlog MySQL binlog file tool
mysqladmin MySQL Server admin tool
ndb_restore Backup restoration tool
ndb_desc NdbApi table description tool
ndb_select_all NdbApi table SELECT * tool
ndb_select_count NdbApi table SELECT COUNT(1) tool
ndb_error_reporter Error report gathering tool
ndbinfo_select_all NdbInfo tool
ndb_waiter State change handling tool

25 © 2020 Oracle
Introduction √
Installation √
Configuration
Starting a cluster
High Availability
Backup and Restore
NdbInfo views
Configuration
- Create directories for each cluster process
- Create a cluster configuration file
- Create MySQLD configuration files
- Initialise MySQLD data directories

26 © 2020 Oracle
Configuration
Configuration summary
- Four Data nodes (1,2,3,4), two per
NodeGroup {1,2}, {3,4}
- One Management server (10)
- Three MySQLDs :
- MySQLD1 Binlogging (11)
- MySQLD2 Binlogging (12)
- MySQLD3 (13)
Full instructions in section 2 of cluster_tutorial.txt
MGMD
NDBD
NDBD
NDBD
NDBD
MY MY MY11 12 13
1
2 4
3
10

27 © 2020 Oracle
Introduction √
Installation √
Configuration √
Starting a cluster
High Availability
Backup and Restore
NdbInfo views
Starting a cluster
- Starting the Management Server (MGMD)
- Starting the Data nodes (NDBD)
- Starting the MySQL Servers (MySQLD)
- Connecting to the MySQL Servers

28 © 2020 Oracle
Starting a cluster
Start the management node (MGMD)
MGMD 10

2
29 © 2020 Oracle
Starting a cluster
Start the data nodes (NDBD)
MGMD 10
NDBD
NDBD
NDBD
NDBD1
4
3

2
30 © 2020 Oracle
Starting a cluster
Start the MySQLD nodes
MGMD 10
NDBD NDBD1
4
3
MY MY MY11 12 13
NDBD NDBD

2
31 © 2020 Oracle
Starting a cluster
Start the MySQLD nodes
User mysql clients to connect to
MySQLDs
Full instructions in section 3 of cluster_tutorial.txt MGMD 10
NDBD NDBD1
4
3
MY MY MY11 12 13
NDBD NDBD
mysql1 mysql2 mysql3

32 © 2020 Oracle
Introduction √
Installation √
Configuration √
Starting a cluster √
High Availability
Backup and Restore
NdbInfo views
- Using ndb_mgm
- Looking at logs (optional)
- Work with data
- Look at binary logs (optional)

33 © 2020 Oracle
Exploring the cluster : Using ndb_mgm
ndb_mgm> show
Connected to Management Server at: localhost:1186
Cluster Configuration

[ndbd(NDB)] 4 node(s)
id=1 @127.0.0.1  (mysql8.0.19 ndb8.0.19, Nodegroup: 0, *)
id=2 @127.0.0.1  (mysql8.0.19 ndb8.0.19, Nodegroup: 0)
[ndb_mgmd(MGM)] 1 node(s)
id=10 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
[mysqld(API)] 7 node(s)
id=11 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=12 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=13 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=14 (not connected, accepting connect from any host)
2
MGMD 10
NDBD NDBD1
4
3
MY MY MY11 12 13
NDBD NDBD
ndb_mgmSHOW

34 © 2020 Oracle
Exploring the cluster : Inserting data
mysql1> create database tutorial;
Query OK, 1 row affected (0.14 sec)

mysql1> use tutorial;
Database changed
mysql1> # Note the 'engine=ndb' suffix
mysql1> create table attendees(person_id int primary key,
name varchar(30)) engine=ndb;
Query OK, 0 rows affected (0.53 sec)
mysql1>
mysql1> insert into attendees values (1, "P Calculus");
mysql1> insert into attendees values (2, "B Castafiore");
mysql1> insert into attendees values (3, "Snowy Dog");
…
mysql1> insert into attendees values (9, "R Rackham");
2
MGMD 10
NDBD NDBD1
4
3
MY MY MY11 12 13
NDBD NDBD
ndb_mgm
tutorial.attendees
INSERT

35 © 2020 Oracle
Exploring the cluster : Reading data
mysql1> select * from attendees;
+++
| person_id | name          |
+++
|         9 | R Rackham     |
|         7 | Alcazar       |
|         3 | Snowy Dog     |
|         6 | Dr Muller     |
|         2 | B Castafiore  |
|         4 | Nestor        |
|         5 | Rastapopoulos |
|         1 | P Calculus    |
|         8 | Ottokar       |
+++
9 rows in set (0.00 sec)
…
…
Shell > ndb_select_all dtutorial attendees
2
MGMD 10
NDBD NDBD1
4
3
MY MY MY11 12 13
NDBD NDBD
ndb_mgm
tutorial.attendees
SELECT
ndb_select_all
Full instructions in section 4 of
cluster_tutorial.txt

36 © 2020 Oracle
Introduction √
Installation √
Configuration √
Exploring the cluster √
High Availability
Backup and Restore
NdbInfo views
High Availability
- Kill one data node process
- Suspend another data node process (optional)
- Restart one data node process and kill another
- Kill one binlogging MySQLD process
- Kill all MySQLD processes (optional)
- Restart all MySQLD processes (optional)
- Kill all data nodes
- Restart all data nodes

37 © 2020 Oracle
High Availability : Kill one data node process
2
MGMD 10
NDBD
4
3
MY MY MY11 12 13
NDBD NDBD
ndb_mgm
tutorial.attendees
SELECT SELECT
ndb_mgm> show

id=1 (not connected, accepting connect from localhost)
id=10 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=11 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=12 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=13 @127.0.0.1  (mysql8.0.19 ndb8.0.19)

38 © 2020 Oracle
High Availability : Suspend another data node process (opt)
tutorial.attendees
ndb_mgm> show

id=10 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=11 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=12 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=13 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
2
MGMD 10
NDBD
4
3
MY MY MY11 12 13
NDBD NDBD
ndb_mgm
SELECT SELECT
SUSPEND

39 © 2020 Oracle
High Availability : Restart one data node + kill another
tutorial.attendees
ndb_mgm> show

id=10 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=11 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=12 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=13 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
MGMD 10
NDBD NDBD1 3
MY MY MY11 12 13
ndb_mgm
SELECT SELECT
ndb_select_all

40 © 2020 Oracle
High Availability : Kill one Binlogging MySQLD process
tutorial.attendees
ndb_mgm> show

id=10 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=12 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=13 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
MGMD 10
NDBD NDBD1 3
MY MY12 13
mysql2 mysql3
ndb_mgm

41 © 2020 Oracle
High Availability : Kill all MySQLD processes (opt)
tutorial.attendees
ndb_mgm> show

id=10 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
MGMD 10
NDBD NDBD1 3
ndb_mgm
ndb_select_all

42 © 2020 Oracle
High Availability : Restart all MySQLD processes (opt)
tutorial.attendees
ndb_mgm> show

id=10 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=11 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=12 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=13 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
MGMD 10
NDBD NDBD1 3
MY MY MY11 12 13
ndb_mgm
SELECT SELECT

43 © 2020 Oracle
High Availability : Kill all data node processes
ndb_mgm> show

id=10 @127.0.0.1 (mysql8.0.19 ndb8.0.19)
MGMD 10
MY MY MY11 12 13
ndb_mgm
SELECT SELECT

44 © 2020 Oracle
High Availability : Restart all data node processes
ndb_mgm> show

id=10 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=11 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=12 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
id=13 @127.0.0.1  (mysql8.0.19 ndb8.0.19)
2
MGMD 10
NDBD NDBD1
4
3
MY MY MY11 12 13
NDBD NDBD
ndb_mgm
SELECT SELECT SELECT
ndb_select_all
tutorial.attendees

45 © 2020 Oracle
Introduction √
Installation √
Configuration √
High Availability √
Backup and Restore
NdbInfo views
Backup and Restore
- Taking a backup
- Looking at backup filesets (optional)
- Restoring a backup (optional)

46 © 2020 Oracle
Backup and Restore : Taking a backup
2
MGMD 10
NDBD NDBD1
4NDBD NDBD
ndb_mgm
3
START BACKUP
1-1
1-2
1-3
1-4
1-1 1-2 1-3 1-4
ndb@ndbVirtualBox:~/cluster1/ndbd1/BACKUP/BACKUP1$ ls lh
total 60K
rwrwr 1 ndb ndb  14K Jan 23 16:36 BACKUP10.1.Data
rwrwr 1 ndb ndb  29K Jan 23 16:36 BACKUP1.1.ctl
rwrwr 1 ndb ndb   52 Jan 23 16:36 BACKUP1.1.log
total 60K
total 60K
...

47 © 2020 Oracle
Backup and Restore : Restoring a backup (optional)
2
MGMD 10
NDBD NDBD1
4NDBD NDBD
ndb_mgm
3
ndb_restore –restoremeta b1 n1 1-1
1-1 1-2 1-3 1-4
ndb_restore –restoredata b1 n1 1-1
Data restore can be very parallel.
In 8.0, ndb_restore is thread-parallel
Backup is logical, target cluster
topology can be different
Metadata/schema can also be
restored or altered via MySQLD

48 © 2020 Oracle
Introduction √
Installation √
Configuration √
Backup and Restore √
NdbInfo views
Joins, Foreign keys and JSON
MySQL Cluster is a relational database, supporting
cross-table joins, foreign key constraints and other
useful features.
We can see some of these features in use by adding
some more data to the tutorial database.

49 © 2020 Oracle
Joins, Foreign keys and JSON : Joins
Add two new tables, with a common
primary key
Execute a join across them.
NDBD 1 NDBD 2
NDBD 3 NDBD 4
MYSQLD1
mysql1
1
2
3 3
3
4
4 4
4
5 5
55
6

51 © 2020 Oracle
Joins, Foreign keys and JSON : JSON
Store invites as JSON documents.
Then add foreign key constraints on
the JSON content.

52 © 2020 Oracle
Introduction √
Installation √
Configuration √
Joins, Foreign Keys, JSON √
NdbInfo views
NdbInfo views
The NdbInfo database contains views on
dynamically generated NdbInfo tables.
These tables are dynamically generated by the data
nodes to give visibility into all kinds of internal state
of the cluster.
In this section we look at some of the view
definitions.

54 © 2020 Oracle
NdbInfo views
mysql1> select * from transporters where remote_node_id=11;
+++++++
+++++
| node_id | remote_node_id | status    | remote_address | bytes_sent | bytes_received | connect_count |
overloaded | overload_count | slowdown | slowdown_count |
+++++++
+++++
|       1 |             11 | CONNECTED | 127.0.0.1      |   34078060 |       29591428 |             1 |
    0 |              0 |        0 |              0 |
|       2 |             11 | CONNECTED | 127.0.0.1      |   34001980 |       29545264 |             1 |
    0 |              0 |        0 |              0 |
|       3 |             11 | CONNECTED | 127.0.0.1      |   34091396 |       29551204 |             1 |
    0 |              0 |        0 |              0 |
|       4 |             11 | CONNECTED | 127.0.0.1      |   34006516 |       29548688 |             1 |
    0 |              0 |        0 |              0 |
+++++++
+++++

55 © 2020 Oracle
Introduction √
Installation √
Configuration √
NdbInfo views √
In MySQL Cluster 8.0, the Synchronized Privileges
feature allows user accounts and privileges to be
synchronized across all MySQLDs attached to a
cluster.

56 © 2020 Oracle
2
MGMD 10
NDBD NDBD1
4
3
MY MY MY11 12 13
NDBD NDBD
ndb_mgm
root root root
audrey
hercule hercule hercule ndb_stored_user privilege
MySQLD - local users

57 © 2020 Oracle
Introduction √
Installation √
Configuration √
NdbInfo views √
Synchronized Privileges √
MySQL Cluster allows a cluster to be scaled without
any downtime, by adding MySQLD nodes, or data
nodes.
Next we will try out this functionality by adding a
new nodegroup (two data nodes) to our cluster, and
then rebalancing some of our tables across the
larger cluster.

58 © 2020 Oracle
Addnode and Rebalance data : Initial state
First we will add some more rows to the beer_pref table to better show balance
    insert into beer_pref select person_id+9, beer from beer_pref;
    …
    insert into beer_pref select person_id+288, beer from beer_pref;
Then we look at the balance across the four existing data nodes using a query on the
memory_per_fragment NdbInfo view :
      +++
      | node_id | sum(fixed_elem_count) |
      +++
      |       1 |                   293 |
      |       2 |                   293 |
      |       3 |                   283 |
      |       4 |                   283 |
      +++

59 © 2020 Oracle
Addnode and Rebalance data : Change configuration
Next we modify the cluster configuration file to add two new data nodes, numbers 5 and 6

     +[ndbd]
     +NodeId = 5
     +HostName = localhost
     +DataDir = /home/ndb/cluster1/ndbd5
     +
     +[ndbd]
     +NodeId = 6
     +HostName = localhost
     +DataDir = /home/ndb/cluster1/ndbd6
     +

60 © 2020 Oracle
Addnode and Rebalance data : Rolling restart
Next we perform a rolling restart of all
the nodes so that they pick up the
new configuration.
MGMD
NDBD 1
NDBD 2
NDBD 3
NDBD 4
MySQLD1
MySQLD2
MySQLD3
2
MGMD 10
NDBD NDBD1
4
3
MY MY MY11 12 13
NDBD NDBD

61 © 2020 Oracle
Addnode and Rebalance data : Start new datanodes
Next we create directories for the new
datanodes, and start them up.
They are not usable for data until a
nodegroup is created for them.
2
MGMD 10
NDBD NDBD1
4
3
MY MY MY11 12 13
NDBD NDBD
NDBD
6
5
NDBD

62 © 2020 Oracle
Addnode and Rebalance data : Create nodegroup
Next we create a new nodegroup containing
the new nodes.
Now the new nodes will be used to store
partitions of any newly created tables.
Existing tables continue to only use the original
nodegroups until they are reorganized.
2
MGMD 10
NDBD NDBD1
4
3
MY MY MY11 12 13
NDBD NDBD
NDBD
6
5
NDBD

63 © 2020 Oracle
Addnode and Rebalance data : Rebalance data
Finally we will rebalance the beer_pref table using an ALTER TABLE command :
            ALTER TABLE REORGANIZE PARTITION beer_pref;
Then we look at the balance across the six data nodes using a query on the
memory_per_fragment NdbInfo view :
      +++
      | node_id | rowcount |
      +++
      |       1 |      198 |
      |       2 |      198 |
      |       3 |      188 |
      |       4 |      188 |
      |       5 |      190 |
      |       6 |      190 |
      +++

64 © 2020 Oracle
Introduction √
Installation √
Configuration √
NdbInfo views √
Synchronized Privileges √
Addnode and Rebalance data √
MySQL Ndb 8.0 Cluster tutorial summary
There are many other features not described in this
tutorial including :
- Asynchronous replication
- Index statistics
- Main memory vs Disk column storage
- Online index build
- Online upgrade
- Optimisation
The full set of features are described in the manual
which can be found at :
https://dev.mysql.com/doc/refman/8.0/en/mysql-
cluster.html
MySQL Cluster development continues alongside
the development of the MySQL Server version 8.0

MySQL Cluster 8.0 tutorial

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