NDB Cluster Disk Data Tables •For more information about the  CREATE TABLESPACE  and  ALTER TABLESPACE  statements, see Section 13.1.21, “CREATE TABLESPACE Statement” , and Section 13.1.10, “ALTER TABLESPACE Statement” . 3.  Now it is possible to create a table whose unindexed columns are stored on disk using files in tablespace  ts_1 : TABLESPACE ts_1 STORAGE DISK  tells the  NDB  storage engine to use tablespace  ts_1  for data storage on disk. Once table  ts_1  has been created as shown, you can perform  INSERT ,  SELECT ,  UPDATE , and DELETE  statements on it just as you would with any other MySQL table. It is also possible to specify whether an individual column is stored on disk or in memory by using a STORAGE  clause as part of the column’s definition in a  CREATE TABLE  or  ALTER TABLE  statement. STORAGE DISK  causes the column to be stored on disk, and  STORAGE MEMORY  causes in-memory storage to be used. See Section 13.1.20, “CREATE TABLE Statement” , for more information. You can obtain information about the  NDB  disk data files and undo log files just created by querying the FILES  table in the  INFORMATION_SCHEMA  database, as shown here: For more information and examples, see Section 26.3.15, “The INFORMATION_SCHEMA FILES Table” . Indexing of columns implicitly stored on disk.   For table  dt_1  as defined in the example just shown, only the  dob  and  joined  columns are stored on disk. This is because there are indexes on the  id , last_name , and  first_name  columns, and so data belonging to these columns is stored in RAM. Only nonindexed columns can be held on disk; indexes and indexed column data continue to be stored in memory. This tradeoff between the use of indexes and conservation of RAM is something you must keep in mind as you design Disk Data tables. You cannot add an index to a column that has been explicitly declared  STORAGE DISK , without first changing its storage type to  MEMORY ; any attempt to do so fails with an error. A column which  implicitly 4501 CREATE TABLE dt_1 ( member_id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, last_name VARCHAR(50) NOT NULL, first_name VARCHAR(50) NOT NULL, dob DATE NOT NULL, joined DATE NOT NULL, INDEX(last_name, first_name) ) TABLESPACE ts_1 STORAGE DISK ENGINE NDBCLUSTER; mysql>  SELECT FILE_NAME AS File, FILE_TYPE AS Type, TABLESPACE_NAME AS Tablespace, TABLE_NAME AS Name, LOGFILE_GROUP_NAME AS ’File group’, FREE_EXTENTS AS Free, TOTAL_EXTENTS AS Total FROM INFORMATION_SCHEMA.FILES WHERE ENGINE=’ndbcluster’; 4 rows in set (0.00 sec) +--------------+----------+------------+------+------------+------+---------+ | File | Type | Tablespace | Name | File group | Free | Total | +--------------+----------+------------+------+------------+------+---------+ | ./undo_1.log | UNDO LOG | lg_1 | NULL | lg_1 | 0 | 4194304 | | ./undo_2.log | UNDO LOG | lg_1 | NULL | lg_1 | 0 | 3145728 | | ./data_1.dat | DATAFILE | ts_1 | NULL | lg_1 | 32 | 32 | | ./data_2.dat | DATAFILE | ts_1 | NULL | lg_1 | 48 | 48 | +--------------+----------+------------+------+------------+------+---------+