ASA Database Administration Guide
Working with Database Files
This section describes how to use additional database files, known as dbspaces.
Typically needed for large databasesFor most databases, a single database file is sufficient. However, for users of large databases, additional database files are often necessary. Additional database files are also convenient tools for clustering related information in separate files. |
When you initialize a database, it contains one database file. This first database file is called the main file. All database objects and all data are placed, by default, in the main file.
Each database file has a maximum allowable size of 256M database pages. For example, a database file created with a database page size of 4 kb can grow to a maximum size of one terabyte (256M*4 kb). However, in practice, the maximum file size allowed by the physical file system in which the file is created affects the maximum allowable size significantly.
While many commonly-employed file systems restrict file size to a maximum of 2 Gb, some, such as the Windows NT/2000/XP file system, allow you to exploit the full database file size. In scenarios where the amount of data placed in the database exceeds the maximum file size, it is necessary to divide the data into more than one database file. As well, you may wish to create multiple dbspaces for reasons other than size limitations, for example to cluster related objects.
If you wish to split existing database objects among several dbspaces, you need to unload your database and modify the generated command file for rebuilding the database. To do so, add IN clauses to specify the dbspace for each table you do not wish to place in the main file.
For more information, see UNLOAD TABLE statement and Setting properties for database objects.
Creating a dbspace
Deleting a dbspace
Pre-allocating space for database files