In this chapter you will learn how to use Enterprise Manager
to explore the structure of your database. In addition, you will learn how to
make a number of changes to your database storage structure.
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You can use Enterprise Manager to manage the storage structures
in your database. In this section you'll access the pages for different storage
structures to become familiar with their contents. In later sections you'll
use the pages to manage the storage structure in your database.
Follow the steps below to use Enterprise Manager to explore
the storage structure of your database:
1.
Click Administration on the Database Home
page to access the Administration property page.
2.
Click Control Files in the Storage section
to access the Control Files page.
The control files and their status is displayed on the Control Files General page. There are two other property pages, in addition to the
General page, for viewing control file information. Click Advanced
to view additional information about the control file.
The Advanced page details information about the
database stored in the control file. Click Record Section to view
information stored in the control file.
The Record Section page displays detailed information
about the control file record section. Return to the Administration
page by clicking the database link at the top of the page.
3.
Click Tablespaces on the Administration page
to access the Tablespaces property page. The Tablespaces
page provides high-level information about tablespace structure and space
usage. You can see how much space is allocated for the tablespace and
what portion of it is used.
Select the Example tablespace and click View
to display more information about the tablespace.
You see more information about the tablespace. Return
to the Administration page by clicking the database link at the
top of the page.
4.
Click Datafiles on the Administration page
to access the Datafiles property page. The Datafiles page
provides a list of the datafiles that comprise your database.
Select the example01.dbf
datafile and click View.
You see more information about the datafile. Return
to the Administration page by clicking the database link at the
top of the page.
5.
Click Redo Log Groups on the Administration page to access the Redo Log Groups property page. The Redo Log Groups page shows the attributes of the redo log groups for your
database.
Return to the Administration page by clicking
the database link at the top of the page.
6.
Click Archive Logs on the Administration page
to access the Archive Logs property page. The Archive Logs
page shows the attributes of the archived redo log files for your database.
Return to the Administration page by clicking
the database link at the top of the page.
In this section you will learn how to create a new tablespace
for your database.
Perform the steps listed below to create the FSDATA
tablespace. This tablespace will be used to store the tables of your database.
Repeat these steps to create the FSINDEX
tablespace which will be used for storage of the indexes in your database.
1.
Click Tablespaces on the Administration page
to access the Tablespaces property page.
Click Create.
2.
The Create Tablespace page appears. Enter FSDATA
in the Name field. Select Locally Managed under the Extent
Management heading. Select Permanent under the Type
heading. Select Read Write under the Status heading. Click
Add in the Datafiles region of the page.
3.
The Add Datafile page appears.
Enter a file name in the File Name field on the Add Datafiles
page. Accept the defaults for the File Directory and File Size
or enter new values. Select Automatically extend datafile when full
(AUTOEXTEND) and specify an amount in the Increment field by which
you want to extend the datafile each time it fills. Click Continue.
4.
You are returned to the Create Tablespace General page. Click the Storage tab.
5.
The Storage page appears. Accept all of the defaults
on the Storage page. Click OK to create your tablespace.
6.
You are returned to the Tablespaces page where
you receive a confirmation of the creation of the tablespace. You can
view your new tablespace in the Results region.
7.
Repeat steps 2 through 6 to create the FSINDEX
tablespace. This tablespace will be used to store the indexes in your
database.
You can modify a tablespace using Enterprise Manager. You
can add additional space to the tablespace by adding datafiles or extending
the existing datafiles. In addition you can enable automatic extension so that
the tablespace will automatically extend when full. There are a number of other
changes you can make including changing space thresholds and changing the tablespace
status to offline.
In this example you will change the automatic extension increment for the UNDOTBS1
tablespace and specify an upper limit for the datafile belonging to the tablespace.
Follow the steps below to modify the UNDOTBS1
tablespace:
1.
Click Tablespaces on the Administration page
to access the Tablespaces property page. Select UNDOTBS1
and click Edit.
2.
The Edit Tablespace page appears. Select the
datafile associated with the tablespace and click Edit.
3.
The Edit Datafile page appears. Select Automatically
extend datafile when full (AUTOEXTEND). Specify 1
MB for the increment value and 60
MB for the maximum file size. Click Continue.
4.
The Edit Tablespace page appears. Click Apply.
5.
An update message is displayed confirming your change. Click the database link to return to the Administration page.
You can multiplex your redo log by adding additional members
to each redo log group.
Follow the steps below to add a new member to each of your
redo log groups:
1.
Click Redo Log Groups in the Storage subsection
on the Administration page to access the Redo Log Groups property
page.
2.
Select group 1 and click Edit, or click the group
number link. The Edit Redo Log Group page appears.
3.
Click Add in the Redo Log Members section. The
Add Redo Log Member page appears.
4.
Enter redo01a.log
for the Name and enter the file directory. Click Continue. Note: You can create your new member in the same directory, but
it is recommended that you store
members on separate drives. If there is a drive failure, you will still
have one member for the log writer to use.
5.
The Edit Redo Log Group page is again displayed.
Verify your entry and click Apply to add your new member.
6.
You receive a confirmation of the addition of a new
member to your log group.
7.
Return to the Redo Log Groups property page and
repeat steps 3 through 7 for each of your log groups using the file naming
convention: redo<group number>a.log.
Undo management entails storing the changes of database transactions
long enough to accommodate rollback, read consistency, and flashback features.
Auto-tuning of the undo retention period is enabled when you create your database.
In this section, you will perform the following tasks:
You can use the Undo Management page to view undo configuration,
including the auto-tuned undo retention period, its low threshold retention
period, and the name and size of the undo tablespace. Auto-tuning of undo retention
cannot be disabled.
You can access the Undo Management page as follows:
1.
Click Administration on the Database Home
page to access the Administration property page.
2.
Click Undo Management in the Database Configuration region to access the Undo Management page.
3.
The Undo Management page is displayed. Click the database link to return to the Administration page.
The undo tablespace is set to auto-extend by default when
you use DBCA to configure your database. If your undo tablespace is not auto-extensible,
you may need to extend the tablespace. You can use the undo advisor to obtain
advise on the undo tablespace size.
You can access the undo advisor as follows:
1.
Click Administration on the Database Home
page to access the Administration property page.
2.
Click Undo Management in the Database Configuration
region to access the Undo Management page.
3.
The Undo Management page is displayed. Click Undo Advisor.
4.
The Undo Advisor page is displayed. On the top
of the page you can see the current auto-tuned undo retention time and
undo tablespace size.
5.
Assume that you have determined the duration of your
longest running query is 60 minutes. Enter 60 in the New Undo
Retention field and choose a time period for analysis from the
Analysis Time Period drop-down menu. The page is refreshed based on your input.
6.
The tablespace size required to meet your specifications is displayed in the Analysis section.
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