Database Reference
In-Depth Information
Figure 9-1: Availability of tablespace to the users can be controlled
using ALTER TABLESPACE statement. SYSTEM tablespace can
never be placed in the OFFLINE mode as Oracle utilizes the tables
relating to data dictionary views and dynamic performance view in its
normal operation.
You can control the availability of tablespaces using the ALTER
TABLESPACE statement e.g. you can make them READ ONLY
or ONLINE/OFFLINE. Once you put the tablespace READ
ONLY then no operation besides SELECT statement is allowed
on that tablespace. By default once you start the Oracle database,
all the tablespaces would be online unless you take a tablespace
offline using the OFFLINE clause in the ALTER
TABLESPACE command. The application of each of these will
come in the backup and recovery chapter then their purpose will
get clearer. Let's discuss each of these statements in the
following lines one by one.
ALTER TABLESPACE users OFFLINE NORMAL;
With NORMAL clause, Oracle writes all the dirty buffer blocks
to the data files associated with that tablespace before taking it
offline. All the data files associated with the tablespace needs to
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