From
the Server tab on the home page, click the Tablespaces link. You will be presented with a list of
existing tablespaces; click the Create button. In Figure 7-1, we??™re creating a new undo tablespace
named UNDO_BATCH. Specify Undo Retention Guarantee as well. I??™ll explain how that works
later in this chapter.
At the bottom of the screen, click Add and specify the name of the datafile to use for the undo
tablespace, as indicated in Figure 7-2. In this example, you use the ASM disk group DATA for the
datafile with a size of 500MB and 100MB more each time it extends. Click Continue to return to
the page in Figure 7-1.
Clicking Storage allows us to specify extent allocation, although for an undo tablespace it
must be automatic. If we are supporting multiple block sizes, we can specify the block size for
the undo tablespace. Figure 7-3 shows that we are specifying automatic extent allocation and a
block size of 8192, the default and only block size defined for the database.
212 Oracle Database 11g DBA Handbook
FIGURE 7-1 Using EM Database Control to create an undo tablespace
FIGURE 7-2 Specifying a datafile for a new undo tablespace
Chapter 7: Managing Transactions with Undo Tablespaces 213
As with most every EM Database Control maintenance screen, we can view the actual SQL
commands that will be executed when we are ready to create the tablespace. In Figure 7-4, we
clicked the Show SQL button to preview the SQL commands used to create the tablespace.
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