Tablespace
lastmod 2021-03-03created 2021-02-251 edits
A tablespace is the space where the actual data in database objects is stored. It is a physical part of the database, and it allocates storage (segments) for all DBMS-managed segments.
A database segment is one of the database objects and occupies physical space, like a table or an index. Once a tablespace is created, it is referenced by name when database segments are created.
A tablespace only specifies the location of database storage; it does not specify the logical database structure or schema. For example, different objects in the same schema can be placed in different tablespaces. Likewise, a single tablespace can serve multiple segments.
Tablespaces let administrators control disk layout. A common use in databases is to optimize performance. For example, a frequently used index can be placed on a fast SCSI disk. Conversely, rarely used database tables can be stored on cheap, slow IDE disks.
While tablespaces usually store data on a file system, some DBMSs are configured with O/S devices called raw devices, eliminating the overhead of the operating system's file system and providing faster performance.