Extract(Read) > Transform(Test&Apply) > Load(Learn) Blog

December 27, 2006

The Storage Hierarchy Summary in an Oracle Database

Filed under: Oracle Concepts and Architecture — H.Tonguç Yılmaz @ 6:44 pm

In summary, the hierarchy of storage in Oracle is as follows:

* A database is made up of one or more tablespaces.
* A tablespace is made up of one or more data files. These files might be cooked files in a file system, raw partitions, ASM managed database files, or a file on a clustered file system. A tablespace contains segments.
* A segment (TABLE, INDEX, and so on) is made up of one or more extents. A segment exists in a tablespace, but may have data in many data files within that tablespace.
* An extent is a logically contiguous set of blocks on disk. An extent is in a single tablespace and, furthermore, is always in a single file within that tablespace.
* A block is the smallest unit of allocation in the database. A block is the smallest unit of I/O used by a database.

References used : Oracle® Database Concepts 10g Release 2 (10.2)

Leave a Comment »

No comments yet.

RSS feed for comments on this post. TrackBack URI

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Blog at WordPress.com.

%d bloggers like this: