MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0
In this section we provide a detailed example illustrating how to add new NDB Cluster data nodes online, starting with an NDB Cluster having 2 data nodes in a single node group and concluding with a cluster having 4 data nodes in 2 node groups.
Starting configuration.
For purposes of illustration, we assume a minimal
configuration, and that the cluster uses a
config.ini file containing only the
following information:
[ndbd default] DataMemory = 100M IndexMemory = 100M NoOfReplicas = 2 DataDir = /usr/local/mysql/var/mysql-cluster [ndbd] Id = 1 HostName = 198.51.100.1 [ndbd] Id = 2 HostName = 198.51.100.2 [mgm] HostName = 198.51.100.10 Id = 10 [api] Id=20 HostName = 198.51.100.20 [api] Id=21 HostName = 198.51.100.21
We have left a gap in the sequence between data node IDs and other nodes. This make it easier later to assign node IDs that are not already in use to data nodes which are newly added.
We also assume that you have already started the cluster using
the appropriate command line or my.cnf
options, and that running
SHOW in the management
client produces output similar to what is shown here:
-- NDB Cluster -- Management Client --
ndb_mgm> SHOW
Connected to Management Server at: 198.51.100.10:1186
Cluster Configuration
---------------------
[ndbd(NDB)] 2 node(s)
id=1 @198.51.100.1 (8.0.24-ndb-8.0.24, Nodegroup: 0, *)
id=2 @198.51.100.2 (8.0.24-ndb-8.0.24, Nodegroup: 0)
[ndb_mgmd(MGM)] 1 node(s)
id=10 @198.51.100.10 (8.0.24-ndb-8.0.24)
[mysqld(API)] 2 node(s)
id=20 @198.51.100.20 (8.0.24-ndb-8.0.24)
id=21 @198.51.100.21 (8.0.24-ndb-8.0.24)
Finally, we assume that the cluster contains a single
NDBCLUSTER table created as shown
here:
USE n;
CREATE TABLE ips (
id BIGINT NOT NULL AUTO_INCREMENT PRIMARY KEY,
country_code CHAR(2) NOT NULL,
type CHAR(4) NOT NULL,
ip_address VARCHAR(15) NOT NULL,
addresses BIGINT UNSIGNED DEFAULT NULL,
date BIGINT UNSIGNED DEFAULT NULL
) ENGINE NDBCLUSTER;
The memory usage and related information shown later in this section was generated after inserting approximately 50000 rows into this table.
In this example, we show the single-threaded ndbd being used for the data node processes. You can also apply this example, if you are using the multithreaded ndbmtd by substituting ndbmtd for ndbd wherever it appears in the steps that follow.
Step 1: Update configuration file.
Open the cluster global configuration file in a text editor
and add [ndbd] sections corresponding to
the 2 new data nodes. (We give these data nodes IDs 3 and 4,
and assume that they are to be run on host machines at
addresses 198.51.100.3 and 198.51.100.4, respectively.) After
you have added the new sections, the contents of the
config.ini file should look like what is
shown here, where the additions to the file are shown in bold
type:
[ndbd default]
DataMemory = 100M
IndexMemory = 100M
NoOfReplicas = 2
DataDir = /usr/local/mysql/var/mysql-cluster
[ndbd]
Id = 1
HostName = 198.51.100.1
[ndbd]
Id = 2
HostName = 198.51.100.2
[ndbd]
Id = 3
HostName = 198.51.100.3
[ndbd]
Id = 4
HostName = 198.51.100.4
[mgm]
HostName = 198.51.100.10
Id = 10
[api]
Id=20
HostName = 198.51.100.20
[api]
Id=21
HostName = 198.51.100.21
Once you have made the necessary changes, save the file.
Step 2: Restart the management server. Restarting the cluster management server requires that you issue separate commands to stop the management server and then to start it again, as follows:
Stop the management server using the management client
STOP command, as shown
here:
ndb_mgm> 10 STOP
Node 10 has shut down.
Disconnecting to allow Management Server to shutdown
shell>
Because shutting down the management server causes the
management client to terminate, you must start the
management server from the system shell. For simplicity, we
assume that config.ini is in the same
directory as the management server binary, but in practice,
you must supply the correct path to the configuration file.
You must also supply the
--reload or
--initial option so that
the management server reads the new configuration from the
file rather than its configuration cache. If your
shell's current directory is also the same as the
directory where the management server binary is located,
then you can invoke the management server as shown here:
shell> ndb_mgmd -f config.ini --reload
2008-12-08 17:29:23 [MgmSrvr] INFO -- NDB Cluster Management Server. 8.0.24-ndb-8.0.24
2008-12-08 17:29:23 [MgmSrvr] INFO -- Reading cluster configuration from 'config.ini'
If you check the output of
SHOW in the management
client after restarting the ndb_mgm process,
you should now see something like this:
-- NDB Cluster -- Management Client --
ndb_mgm> SHOW
Connected to Management Server at: 198.51.100.10:1186
Cluster Configuration
---------------------
[ndbd(NDB)] 2 node(s)
id=1 @198.51.100.1 (8.0.24-ndb-8.0.24, Nodegroup: 0, *)
id=2 @198.51.100.2 (8.0.24-ndb-8.0.24, Nodegroup: 0)
id=3 (not connected, accepting connect from 198.51.100.3)
id=4 (not connected, accepting connect from 198.51.100.4)
[ndb_mgmd(MGM)] 1 node(s)
id=10 @198.51.100.10 (8.0.24-ndb-8.0.24)
[mysqld(API)] 2 node(s)
id=20 @198.51.100.20 (8.0.24-ndb-8.0.24)
id=21 @198.51.100.21 (8.0.24-ndb-8.0.24)
Step 3: Perform a rolling restart of the existing data nodes.
This step can be accomplished entirely within the cluster
management client using the
RESTART command, as shown
here:
ndb_mgm>1 RESTARTNode 1: Node shutdown initiated Node 1: Node shutdown completed, restarting, no start. Node 1 is being restarted ndb_mgm> Node 1: Start initiated (version 8.0.24) Node 1: Started (version 8.0.24) ndb_mgm>2 RESTARTNode 2: Node shutdown initiated Node 2: Node shutdown completed, restarting, no start. Node 2 is being restarted ndb_mgm> Node 2: Start initiated (version 8.0.24) ndb_mgm> Node 2: Started (version 8.0.24)
After issuing each X
RESTARTNode before proceeding
any further.
X: Started
(version ...)
You can verify that all existing data nodes were restarted using
the updated configuration by checking the
ndbinfo.nodes table in the
mysql client.
Step 4: Perform a rolling restart of all cluster API nodes.
Shut down and restart each MySQL server acting as an SQL node
in the cluster using mysqladmin shutdown
followed by mysqld_safe (or another startup
script). This should be similar to what is shown here, where
password is the MySQL
root password for a given MySQL server
instance:
shell>mysqladmin -uroot -p081208 20:19:56 mysqld_safe mysqld from pid file /usr/local/mysql/var/tonfisk.pid ended shell>passwordshutdownmysqld_safe --ndbcluster --ndb-connectstring=198.51.100.10 &081208 20:20:06 mysqld_safe Logging to '/usr/local/mysql/var/tonfisk.err'. 081208 20:20:06 mysqld_safe Starting mysqld daemon with databases from /usr/local/mysql/var
Of course, the exact input and output depend on how and where
MySQL is installed on the system, as well as which options you
choose to start it (and whether or not some or all of these
options are specified in a my.cnf file).
Step 5: Perform an initial start of the new data nodes.
From a system shell on each of the hosts for the new data
nodes, start the data nodes as shown here, using the
--initial option:
shell> ndbd -c 198.51.100.10 --initial
Unlike the case with restarting the existing data nodes, you can start the new data nodes concurrently; you do not need to wait for one to finish starting before starting the other.
Wait until both of the new data nodes have started
before proceeding with the next step. Once the new
data nodes have started, you can see in the output of the
management client SHOW
command that they do not yet belong to any node group (as
indicated with bold type here):
ndb_mgm> SHOW
Connected to Management Server at: 198.51.100.10:1186
Cluster Configuration
---------------------
[ndbd(NDB)] 2 node(s)
id=1 @198.51.100.1 (8.0.24-ndb-8.0.24, Nodegroup: 0, *)
id=2 @198.51.100.2 (8.0.24-ndb-8.0.24, Nodegroup: 0)
id=3 @198.51.100.3 (8.0.24-ndb-8.0.24, no nodegroup)
id=4 @198.51.100.4 (8.0.24-ndb-8.0.24, no nodegroup)
[ndb_mgmd(MGM)] 1 node(s)
id=10 @198.51.100.10 (8.0.24-ndb-8.0.24)
[mysqld(API)] 2 node(s)
id=20 @198.51.100.20 (8.0.24-ndb-8.0.24)
id=21 @198.51.100.21 (8.0.24-ndb-8.0.24)
Step 6: Create a new node group.
You can do this by issuing a CREATE
NODEGROUP command in the cluster management client.
This command takes as its argument a comma-separated list of
the node IDs of the data nodes to be included in the new node
group, as shown here:
ndb_mgm> CREATE NODEGROUP 3,4
Nodegroup 1 created
By issuing SHOW again, you
can verify that data nodes 3 and 4 have joined the new node
group (again indicated in bold type):
ndb_mgm> SHOW
Connected to Management Server at: 198.51.100.10:1186
Cluster Configuration
---------------------
[ndbd(NDB)] 2 node(s)
id=1 @198.51.100.1 (8.0.24-ndb-8.0.24, Nodegroup: 0, *)
id=2 @198.51.100.2 (8.0.24-ndb-8.0.24, Nodegroup: 0)
id=3 @198.51.100.3 (8.0.24-ndb-8.0.24, Nodegroup: 1)
id=4 @198.51.100.4 (8.0.24-ndb-8.0.24, Nodegroup: 1)
[ndb_mgmd(MGM)] 1 node(s)
id=10 @198.51.100.10 (8.0.24-ndb-8.0.24)
[mysqld(API)] 2 node(s)
id=20 @198.51.100.20 (8.0.24-ndb-8.0.24)
id=21 @198.51.100.21 (8.0.24-ndb-8.0.24)
Step 7: Redistribute cluster data.
When a node group is created, existing data and indexes are
not automatically distributed to the new node group's
data nodes, as you can see by issuing the appropriate
REPORT command in the
management client:
ndb_mgm> ALL REPORT MEMORY
Node 1: Data usage is 5%(177 32K pages of total 3200)
Node 1: Index usage is 0%(108 8K pages of total 12832)
Node 2: Data usage is 5%(177 32K pages of total 3200)
Node 2: Index usage is 0%(108 8K pages of total 12832)
Node 3: Data usage is 0%(0 32K pages of total 3200)
Node 3: Index usage is 0%(0 8K pages of total 12832)
Node 4: Data usage is 0%(0 32K pages of total 3200)
Node 4: Index usage is 0%(0 8K pages of total 12832)
By using ndb_desc with the
-p option, which causes the output to include
partitioning information, you can see that the table still uses
only 2 partitions (in the Per partition info
section of the output, shown here in bold text):
shell> ndb_desc -c 198.51.100.10 -d n ips -p
-- ips --
Version: 1
Fragment type: 9
K Value: 6
Min load factor: 78
Max load factor: 80
Temporary table: no
Number of attributes: 6
Number of primary keys: 1
Length of frm data: 340
Row Checksum: 1
Row GCI: 1
SingleUserMode: 0
ForceVarPart: 1
FragmentCount: 2
TableStatus: Retrieved
-- Attributes --
id Bigint PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY AUTO_INCR
country_code Char(2;latin1_swedish_ci) NOT NULL AT=FIXED ST=MEMORY
type Char(4;latin1_swedish_ci) NOT NULL AT=FIXED ST=MEMORY
ip_address Varchar(15;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORY
addresses Bigunsigned NULL AT=FIXED ST=MEMORY
date Bigunsigned NULL AT=FIXED ST=MEMORY
-- Indexes --
PRIMARY KEY(id) - UniqueHashIndex
PRIMARY(id) - OrderedIndex
-- Per partition info --
Partition Row count Commit count Frag fixed memory Frag varsized memory
0 26086 26086 1572864 557056
1 26329 26329 1605632 557056
NDBT_ProgramExit: 0 - OK
You can cause the data to be redistributed among all of the data
nodes by performing, for each NDB
table, an ALTER
TABLE ... ALGORITHM=INPLACE, REORGANIZE PARTITION
statement in the mysql client.
ALTER TABLE ... ALGORITHM=INPLACE, REORGANIZE
PARTITION does not work on tables that were created
with the MAX_ROWS option. Instead, use
ALTER TABLE ... ALGORITHM=INPLACE,
MAX_ROWS=... to reorganize such tables.
Keep in mind that using MAX_ROWS to set the
number of partitions per table is deprecated, and you should
use PARTITION_BALANCE instead; see
Section 13.1.20.11, “Setting NDB_TABLE Options”, for
more information.
After issuing the statement ALTER TABLE ips
ALGORITHM=INPLACE, REORGANIZE PARTITION, you can see
using ndb_desc that the data for this table
is now stored using 4 partitions, as shown here (with the
relevant portions of the output in bold type):
shell> ndb_desc -c 198.51.100.10 -d n ips -p
-- ips --
Version: 16777217
Fragment type: 9
K Value: 6
Min load factor: 78
Max load factor: 80
Temporary table: no
Number of attributes: 6
Number of primary keys: 1
Length of frm data: 341
Row Checksum: 1
Row GCI: 1
SingleUserMode: 0
ForceVarPart: 1
FragmentCount: 4
TableStatus: Retrieved
-- Attributes --
id Bigint PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY AUTO_INCR
country_code Char(2;latin1_swedish_ci) NOT NULL AT=FIXED ST=MEMORY
type Char(4;latin1_swedish_ci) NOT NULL AT=FIXED ST=MEMORY
ip_address Varchar(15;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORY
addresses Bigunsigned NULL AT=FIXED ST=MEMORY
date Bigunsigned NULL AT=FIXED ST=MEMORY
-- Indexes --
PRIMARY KEY(id) - UniqueHashIndex
PRIMARY(id) - OrderedIndex
-- Per partition info --
Partition Row count Commit count Frag fixed memory Frag varsized memory
0 12981 52296 1572864 557056
1 13236 52515 1605632 557056
2 13105 13105 819200 294912
3 13093 13093 819200 294912
NDBT_ProgramExit: 0 - OK
Normally, ALTER
TABLE is used
with a list of partition identifiers and a set of partition
definitions to create a new partitioning scheme for a table
that has already been explicitly partitioned. Its use here to
redistribute data onto a new NDB Cluster node group is an
exception in this regard; when used in this way, no other
keywords or identifiers follow table_name
[ALGORITHM=INPLACE,] REORGANIZE PARTITIONREORGANIZE
PARTITION.
For more information, see Section 13.1.9, “ALTER TABLE Statement”.
In addition, for each table, the
ALTER
TABLE statement should be followed by an
OPTIMIZE TABLE to reclaim wasted
space. You can obtain a list of all
NDBCLUSTER tables using the
following query against the
INFORMATION_SCHEMA.TABLES table:
SELECT TABLE_SCHEMA, TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES
WHERE ENGINE = 'NDBCLUSTER';
The INFORMATION_SCHEMA.TABLES.ENGINE value
for an NDB Cluster table is always
NDBCLUSTER, regardless of whether
the CREATE TABLE statement used to create
the table (or ALTER TABLE
statement used to convert an existing table from a different
storage engine) used NDB or
NDBCLUSTER in its
ENGINE option.
You can see after performing these statements in the output of
ALL REPORT MEMORY that the
data and indexes are now redistributed between all cluster data
nodes, as shown here:
ndb_mgm> ALL REPORT MEMORY
Node 1: Data usage is 5%(176 32K pages of total 3200)
Node 1: Index usage is 0%(76 8K pages of total 12832)
Node 2: Data usage is 5%(176 32K pages of total 3200)
Node 2: Index usage is 0%(76 8K pages of total 12832)
Node 3: Data usage is 2%(80 32K pages of total 3200)
Node 3: Index usage is 0%(51 8K pages of total 12832)
Node 4: Data usage is 2%(80 32K pages of total 3200)
Node 4: Index usage is 0%(50 8K pages of total 12832)
Since only one DDL operation on
NDBCLUSTER tables can be executed
at a time, you must wait for each
ALTER TABLE ...
REORGANIZE PARTITION statement to finish before
issuing the next one.
It is not necessary to issue
ALTER TABLE ...
REORGANIZE PARTITION statements for
NDBCLUSTER tables created
after the new data nodes have been added;
data added to such tables is distributed among all data nodes
automatically. However, in
NDBCLUSTER tables that existed
prior to the addition of the new nodes,
neither existing nor new data is distributed using the new nodes
until these tables have been reorganized using
ALTER TABLE ...
REORGANIZE PARTITION.
Alternative procedure, without rolling restart. It is possible to avoid the need for a rolling restart by configuring the extra data nodes, but not starting them, when first starting the cluster. We assume, as before, that you wish to start with two data nodes—nodes 1 and 2—in one node group and later to expand the cluster to four data nodes, by adding a second node group consisting of nodes 3 and 4:
[ndbd default] DataMemory = 100M IndexMemory = 100M NoOfReplicas = 2 DataDir = /usr/local/mysql/var/mysql-cluster [ndbd] Id = 1 HostName = 198.51.100.1 [ndbd] Id = 2 HostName = 198.51.100.2 [ndbd] Id = 3 HostName = 198.51.100.3 Nodegroup = 65536 [ndbd] Id = 4 HostName = 198.51.100.4 Nodegroup = 65536 [mgm] HostName = 198.51.100.10 Id = 10 [api] Id=20 HostName = 198.51.100.20 [api] Id=21 HostName = 198.51.100.21
The data nodes to be brought online at a later time (nodes 3 and
4) can be configured with
NodeGroup = 65536, in
which case nodes 1 and 2 can each be started as shown here:
shell> ndbd -c 198.51.100.10 --initial
The data nodes configured with
NodeGroup = 65536 are
treated by the management server as though you had started nodes
1 and 2 using --nowait-nodes=3,4
after waiting for a period of time determined by the setting for
the
StartNoNodeGroupTimeout
data node configuration parameter. By default, this is 15
seconds (15000 milliseconds).
StartNoNodegroupTimeout
must be the same for all data nodes in the cluster; for this
reason, you should always set it in the [ndbd
default] section of the
config.ini file, rather than for
individual data nodes.
When you are ready to add the second node group, you need only perform the following additional steps:
Start data nodes 3 and 4, invoking the data node process once for each new node:
shell> ndbd -c 198.51.100.10 --initial
Issue the appropriate CREATE
NODEGROUP command in the management client:
ndb_mgm> CREATE NODEGROUP 3,4
In the mysql client, issue
ALTER TABLE ...
REORGANIZE PARTITION and
OPTIMIZE TABLE statements for
each existing NDBCLUSTER table.
(As noted elsewhere in this section, existing NDB Cluster
tables cannot use the new nodes for data distribution until
this has been done.)