NAME
ndb_desc - describe NDB tables
SYNOPSIS
ndb_desc options
DESCRIPTION
ndb_desc provides a detailed description of one or more NDB tables.
Usage:
ndb_desc -c connect_string tbl_name -d db_name [-p]
Sample Output:
MySQL table creation and population statements:
USE test;
CREATE TABLE fish (
id INT(11) NOT NULL AUTO_INCREMENT,
name VARCHAR(20) NOT NULL,
length_mm INT(11) NOT NULL,
weight_gm INT(11) NOT NULL,
PRIMARY KEY pk (id),
UNIQUE KEY uk (name)
) ENGINE=NDB;
INSERT INTO fish VALUES
(´´,´guppy´, 35, 2), (´´,´tuna´, 2500, 150000),
(´´,´shark´, 3000, 110000), (´´,´manta ray´, 1500, 50000),
(´´,´grouper´, 900, 125000), (´´,´puffer´, 250, 2500);
Output from ndb_desc:
shell> ./ndb_desc -c localhost fish -d test -p
-- fish --
Version: 2
Fragment type: 9
K Value: 6
Min load factor: 78
Max load factor: 80
Temporary table: no
Number of attributes: 4
Number of primary keys: 1
Length of frm data: 311
Row Checksum: 1
Row GCI: 1
SingleUserMode: 0
ForceVarPart: 1
FragmentCount: 2
TableStatus: Retrieved
-- Attributes --
id Int PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY AUTO_INCR
name Varchar(20;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORY
length_mm Int NOT NULL AT=FIXED ST=MEMORY
weight_gm Int NOT NULL AT=FIXED ST=MEMORY
-- Indexes --
PRIMARY KEY(id) - UniqueHashIndex
PRIMARY(id) - OrderedIndex
uk$unique(name) - UniqueHashIndex
uk(name) - OrderedIndex
-- Per partition info --
Partition Row count Commit count Frag fixed memory Frag varsized memory Extent_space Free extent_space
0 2 2 32768 32768 0 0
1 4 4 32768 32768 0 0
NDBT_ProgramExit: 0 - OK
The Extent_space and Free extent_space columns were added in MySQL
Cluster NDB 6.3.27 and MySQL Cluster NDB 7.0.8. They are applicable
only to NDB tables having columns on disk; for tables having only
in-memory columns, these columns always contain the value 0.
To illustrate their use, we modify the previous example. First, we must
create the necessary Disk Data objects, as shown here:
CREATE LOGFILE GROUP lg_1
ADD UNDOFILE ´undo_1.log´
INITIAL_SIZE 16M
UNDO_BUFFER_SIZE 2M
ENGINE NDB;
ALTER LOGFILE GROUP lg_1
ADD UNDOFILE ´undo_2.log´
INITIAL_SIZE 12M
ENGINE NDB;
CREATE TABLESPACE ts_1
ADD DATAFILE ´data_1.dat´
USE LOGFILE GROUP lg_1
INITIAL_SIZE 32M
ENGINE NDB;
ALTER TABLESPACE ts_1
ADD DATAFILE ´data_2.dat´
INITIAL_SIZE 48M
ENGINE NDB;
(For more information on the statements just shown and the objects
created by them, see Section 17.5.9.1, “MySQL Cluster Disk Data
Objects”, as well as Section 12.1.14, “CREATE LOGFILE GROUP Syntax”,
and Section 12.1.18, “CREATE TABLESPACE Syntax”.)
Now we can create and populate a version of the fish table that stores
2 of its columns on disk (deleting the previous version of the table
first, if it already exists):
CREATE TABLE fish (
id INT(11) NOT NULL AUTO_INCREMENT,
name VARCHAR(20) NOT NULL,
length_mm INT(11) NOT NULL,
weight_gm INT(11) NOT NULL,
PRIMARY KEY pk (id),
UNIQUE KEY uk (name)
) TABLESPACE ts_1 STORAGE DISK
ENGINE=NDB;
INSERT INTO fish VALUES
(´´,´guppy´, 35, 2), (´´,´tuna´, 2500, 150000),
(´´,´shark´, 3000, 110000), (´´,´manta ray´, 1500, 50000),
(´´,´grouper´, 900, 125000), (´´,´puffer´, 250, 2500);
When run against this version of the table, ndb_desc displays the
following output:
shell> ./ndb_desc -c localhost fish -d test -p
-- fish --
Version: 3
Fragment type: 9
K Value: 6
Min load factor: 78
Max load factor: 80
Temporary table: no
Number of attributes: 4
Number of primary keys: 1
Length of frm data: 321
Row Checksum: 1
Row GCI: 1
SingleUserMode: 0
ForceVarPart: 1
FragmentCount: 2
TableStatus: Retrieved
-- Attributes --
id Int PRIMARY KEY DISTRIBUTION KEY AT=FIXED ST=MEMORY AUTO_INCR
name Varchar(20;latin1_swedish_ci) NOT NULL AT=SHORT_VAR ST=MEMORY
length_mm Int NOT NULL AT=FIXED ST=DISK
weight_gm Int NOT NULL AT=FIXED ST=DISK
-- Indexes --
PRIMARY KEY(id) - UniqueHashIndex
PRIMARY(id) - OrderedIndex
uk$unique(name) - UniqueHashIndex
uk(name) - OrderedIndex
-- Per partition info --
Partition Row count Commit count Frag fixed memory Frag varsized memory Extent_space Free extent_space
0 2 2 32768 32768 1048576 1044440
1 4 4 32768 32768 1048576 1044400
NDBT_ProgramExit: 0 - OK
This means that 1048576 bytes are allocated from the tablespace for
this table on each partition, of which 1044440 bytes remain free for
additional storage. In other words, 1048576 - 1044440 = 4136 bytes per
partition is currently being used to store the data from this table´s
disk-based columns. The number of bytes shown as Free extent_space is
available for storing on-disk column data from the fish table only; for
this reason, it is not visible when selecting from the
INFORMATION_SCHEMA.FILES table.
Additional Options:
· --extra-partition-info, -p
Prints additional information about the table´s partitions.
· Information about multiple tables can be obtained in a single
invocation of ndb_desc by using their names, separated by spaces.
All of the tables must be in the same database.
COPYRIGHT
Copyright 2007-2008 MySQL AB, 2009 Sun Microsystems, Inc.
This documentation is free software; you can redistribute it and/or
modify it only under the terms of the GNU General Public License as
published by the Free Software Foundation; version 2 of the License.
This documentation is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License along
with the program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see
http://www.gnu.org/licenses/.
SEE ALSO
For more information, please refer to the MySQL Reference Manual, which
may already be installed locally and which is also available online at
http://dev.mysql.com/doc/.
AUTHOR
Sun Microsystems, Inc. (http://www.mysql.com/).