After we click OK in Figure 7-3, the new undo tablespace is created successfully in Figure 7-5.
Note that EM Database Control, although a big timesaver for the DBA, does not cover every
possible scenario, nor does it prevent the DBA from trying to create an undo tablespace with the
wrong parameters. Earlier in Figure 7-3, we could have specified Uniform extent allocation, but
if you try to create the tablespace, it will fail with an error message. As mentioned earlier in this
chapter, undo tablespaces must have automatically allocated extents.
FIGURE 7-3 Specifying storage characteristics for an undo tablespace
FIGURE 7-4 Previewing SQL commands to create an undo tablespace
214 Oracle Database 11g DBA Handbook
Dropping Undo Tablespaces
Dropping an undo tablespace is similar to dropping any other tablespace; the only restriction is
that the undo tablespace being dropped must not be the active undo tablespace or still have undo
data for an uncommitted transaction. You may, however, drop an undo tablespace that has unexpired
undo information, which may cause a long-running query to fail. To drop the tablespace we created
in the previous section, we use the drop tablespace command:
SQL> drop tablespace undo_batch;
Tablespace dropped.
SQL>
The clause including contents is implied when dropping an undo tablespace. However,
to remove the operating system data files when the tablespace is dropped, you must specify
including contents and datafiles.
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