- 12.1 Data Definition Statements
- 12.1.1 ALTER DATABASE Syntax
- 12.1.2 ALTER EVENT Syntax
- 12.1.3 ALTER LOGFILE GROUP Syntax
- 12.1.4 ALTER FUNCTION Syntax
- 12.1.5 ALTER PROCEDURE Syntax
- 12.1.6 ALTER SERVER Syntax
- 12.1.7 ALTER TABLE Syntax
- 12.1.8 ALTER TABLESPACE Syntax
- 12.1.9 ALTER VIEW Syntax
- 12.1.10 CREATE DATABASE Syntax
- 12.1.11 CREATE EVENT Syntax
- 12.1.12 CREATE FUNCTION Syntax
- 12.1.13 CREATE INDEX Syntax
- 12.1.14 CREATE LOGFILE GROUP Syntax
- 12.1.15 CREATE PROCEDURE and CREATE FUNCTION Syntax
- 12.1.16 CREATE SERVER Syntax
- 12.1.17 CREATE TABLE Syntax
- 12.1.18 CREATE TABLESPACE Syntax
- 12.1.19 CREATE TRIGGER Syntax
- 12.1.20 CREATE VIEW Syntax
- 12.1.21 DROP DATABASE Syntax
- 12.1.22 DROP EVENT Syntax
- 12.1.23 DROP FUNCTION Syntax
- 12.1.24 DROP INDEX Syntax
- 12.1.25 DROP LOGFILE GROUP Syntax
- 12.1.26 DROP PROCEDURE and DROP FUNCTION Syntax
- 12.1.27 DROP SERVER Syntax
- 12.1.28 DROP TABLE Syntax
- 12.1.29 DROP TABLESPACE Syntax
- 12.1.30 DROP TRIGGER Syntax
- 12.1.31 DROP VIEW Syntax
- 12.1.32 RENAME DATABASE Syntax
- 12.1.33 RENAME TABLE Syntax
- 12.1.34 TRUNCATE TABLE Syntax
ALTER LOGFILE GROUPlogfile_groupADD UNDOFILE 'file_name' [INITIAL_SIZE [=]size] [WAIT] ENGINE [=]engine_name
This statement adds an UNDO file named
'file_name' to an existing log file
group logfile_group. An
ALTER LOGFILE GROUP statement has
one and only one ADD UNDOFILE clause. No
DROP UNDOFILE clause is currently supported.
All MySQL Cluster Disk Data objects share the same namespace. This means that each Disk Data object must be uniquely named (and not merely each Disk Data object of a given type). For example, you cannot have a tablespace and an undo log file with the same name, or an undo log file and a data file with the same name.
Prior to MySQL Cluster NDB 6.2.17, 6.3.23, and 6.4.3, path and file names for undo log files could not be longer than 128 characters. (Bug #31769)
The optional INITIAL_SIZE parameter sets the
UNDO file's initial size in bytes; if not
specified, the initial size default to 128M
(128 megabytes). You may optionally follow
size with a one-letter abbreviation for
an order of magnitude, similar to those used in
my.cnf. Generally, this is one of the letters
M (for megabytes) or G (for
gigabytes).
On 32-bit systems, the maximum supported value for
INITIAL_SIZE is 4G. (Bug
#29186)
Beginning with MySQL Cluster NDB 6.2.18, 6.3.24, and 7.0.4, the
minimum permitted value for INITIAL_SIZE is
1M. (Bug #29574)
WAIT is parsed but otherwise ignored. This
keyword has no effect in MySQL 5.1, MySQL Cluster NDB 6.x, or
MySQL Cluster NDB 7.x, and is intended for future expansion.
The ENGINE parameter (required) determines the
storage engine which is used by this log file group, with
engine_name being the name of the
storage engine. In MySQL 5.1, MySQL Cluster NDB 6.x, and MySQL
Cluster NDB 7.x, the only accepted values for
engine_name are
“NDBCLUSTER” and
“NDB”. The two values
are equivalent.
Here is an example, which assumes that the log file group
lg_3 has already been created using
CREATE LOGFILE GROUP (see
Section 12.1.14, “CREATE LOGFILE GROUP Syntax”):
ALTER LOGFILE GROUP lg_3
ADD UNDOFILE 'undo_10.dat'
INITIAL_SIZE=32M
ENGINE=NDBCLUSTER;
When ALTER LOGFILE GROUP is used
with ENGINE = NDBCLUSTER (alternatively,
ENGINE = NDB), an UNDO log
file is created on each MySQL Cluster data node. You can verify
that the UNDO files were created and obtain
information about them by querying the
INFORMATION_SCHEMA.FILES table. For
example:
mysql>SELECT FILE_NAME, LOGFILE_GROUP_NUMBER, EXTRA->FROM INFORMATION_SCHEMA.FILES->WHERE LOGFILE_GROUP_NAME = 'lg_3';+-------------+----------------------+----------------+ | FILE_NAME | LOGFILE_GROUP_NUMBER | EXTRA | +-------------+----------------------+----------------+ | newdata.dat | 0 | CLUSTER_NODE=3 | | newdata.dat | 0 | CLUSTER_NODE=4 | | undo_10.dat | 11 | CLUSTER_NODE=3 | | undo_10.dat | 11 | CLUSTER_NODE=4 | +-------------+----------------------+----------------+ 4 rows in set (0.01 sec)
(See Section 19.8, “The INFORMATION_SCHEMA FILES Table”.)
Memory used for UNDO_BUFFER_SIZE comes from the
global pool whose size is determined by the value of the
SharedGlobalMemory data
node configuration parameter. This includes any default value
implied for this option by the setting of the
InitialLogFileGroup data
node configuration parameter.
ALTER LOGFILE GROUP was added in
MySQL 5.1.6. It is useful only with Disk Data storage for MySQL
Cluster. For more information, see
Section 16.5.11, “MySQL Cluster Disk Data Tables”.
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