2. Data, Space and Transaction Processing
Session id: 40170
The Self-managing Database: Proactive Space and Schema Object Management
Amit Ganesh Director,
Data, Space and Transaction Processing
Oracle Corporation

3. Agenda Proactive Space Management Proactive Undo Management Alerts
Size estimation and growth trending
Segment Advisor and Shrink
Proactive Undo Management
Auto-sizing
Auto-tuning

4. Automatic Space Management
Oracle9i
No external space fragmentations
Locally Managed Tablespace
No space allocation contention
Automatic Segment Space Management
No Rollback Segments
Automatic Undo Management
Application & SQL
Management
Storage
Management
System Resource
Management
Backup & Recovery
Management
Space
Management
Database Management
Intelligent Infrastructure

5. Oracle Database 10g – Self-Managing Database
Application & SQL
Management
Storage
Management
System Resource
Management
Space
Management
Backup & Recovery
Management
Database Management
Database Control
Intelligent Infrastructure

6. 10g: Always working for you
Collects continuously
Records periodically to disk
Learns from historical data
Adapts to changing workload
Alerts DBA when problems occur
Advises proactively on problems
Integrated with the Enterprise Manager

7. Proactive Space Management

8. Proactive Space Management in 10g$$
Operations
Size Estimation
Growth Trending
Planning
Segment
Advisor
Actions
Tablespace
Alerts
Shrink
Add file
Re-org/ rebuild
Resumable

9. Object Size Estimation

10. Tablespace Alerts Database Generated Warning, Critical Out of the box
Tablespaces can be provisioned with more disk space before out-of-space conditions occur

11. Tablespace Thresholds
97% Critical
85% Warning
97% Critical
85% Warning
Locally Managed Tablespace
Alert
Add Files
Add files
Resolve Space
Problem
Free up space
Freeing up space

12. In-Memory Calculation
Alert Computation
MMON
85% Warning
97% Critical
Check every 10 mns
Alert
Cleared
In-Memory Calculation
Read only/Offline tablespaces: Do not setup alerts
Temporary tablespace: Threshold corresponds to space currently used by sessions.
Undo tablespace: Threshold corresponds to space used by active and unexpired extents.
AUTOEXTENSIBLE files: Threshold is based on the maximum file size.

13. Threshold Alert Tracking
SCNt2
10MB
50MB
SCNt1
60MB
100MB
File1
File2
Filen …
File Size
Allocated Space
Change SCN
Instance1
Instance2
MMON
Data aggregated
through GV$
Tablespace Size:
150M Allocated: 70M
Tablespace

14. Setting Thresholds Using EM
Changing database default thresholds
Changing a particular tablespace thresholds
Directly in the context of the tablespace
From the Edit Metric Thresholds page

15. Tablespace Threshold Page

16. Receiving Alerts in EM

17. Growth Trend Report Based on Automatic Workload Repository Data
Indicates past growth trend and predicts future growth pattern

18. Growth Trend Report

19. Segment Advisor
Determines whether an object is a good candidate for a shrink operation
Based on unused space that can be released
Considers estimated future space requirements
EM allows you to apply the recommended shrink
Can be invoked at the segment or tablespace level

20. Segment Shrink Reclaimed Space Shrink Online and In-place Operation
Unused Space
Unused Space
Data
HWM
Shrink
Operation
Online and In-place
Shrink Operation
Reclaimed Space
HWM

21. Better space utilization
Benefits
Online & In-place
Faster access
Shrunk Segment
Better space utilization

22. Auto Segment Space Managed Tablespace
Candidate Segments
Auto Segment Space Managed Tablespace
Tables
LOBs
Row Movement Enabled
IOTs
Materialized Views
Indexes

23. Dependency Maintenance
Indexes are maintained
Index
DBA
Table
Shrink
Shrink
Trigger
Triggers are not fired

24. How Can I Shrink Segments?
ALTER … SHRINK SPACE [CASCADE]
TABLE
INDEX
MATERIALIZED VIEW
MATERIALIZED VIEW LOG
MODIFY PARTITION
MODIFY LOB
MODIFY SUBPARTITION
ALTER TABLE employees SHRINK SPACE CASCADE;
ALTER TABLE employees ENABLE ROW MOVEMENT; 1 2

25. How Does it Work? 1 2 ALTER TABLE employees SHRINK SPACE COMPACT;
HWM
HWM
ALTER TABLE employees SHRINK SPACE; 2
HWM

26. EM Interface

27. Space Management : Before and Now
Scenario: Reclaim Wasted Space
Oracle10G
Launch Segment Advisor to advise on which object(s) to shrink
Accept the recommendations to shrink the objects online and in-place
Before
Check to see which objects in the tablespace have pockets of wasted space due to deletion:
Create a script that looks at DBA_TABLES view to compare the total space allocated for each object (BLOCKS * DB_BLOCK_SIZE) in a tablespace to the estimated space used by the object (AVG_ROW_LEN * NUM_ROWS)
(assumes objects have been analyzed)
Review script output and identify target objects for reorganization
Identify/Create “scratch” tablespace
For each object to be reorganized, use the Enterprise Manager Reorg wizard to recreate each object along with its dependencies

28. Proactive Undo Management

29. Oracle Database 10g Auto-sizing Undo Tablespace
Auto-tuning Undo Retention
Proactive Monitoring
Undo Advisor

30. Auto-sizing Undo Tablespace
A self-learning system
Create Undo tablespace with autoextensible files
Run your workload
Done!
(undo tablespace size adapts to the application)

31. Auto-tuning Undo Retention
Before
Oracle 10g: Auto-tuning
OLTP
DSS
Large RBS/
UR = 5 hrs
Small RBS/
UR = 15 min

32. Proactive Monitoring: Alerts
Out of Undo Space Alert
Long query warning Alert
Out of space Warning
Out of space Critical
ORA-1555 Failure …
7:00am
7:10
7:20
7:30
7:40

33. Undo Advisor Automatically analyzes the undo usage to advice optimal:
Undo tablespace size to support your longest running query
Undo tablespace size for a given undo retention period to support Undo based Flashback toolset

34. Undo Home: Automatic Advice

35. Undo Advisor: What if?

36. Summary
Self-management engineered into the core of Oracle Database 10g
Self-management through:
Auto-sizing and size estimation
Built-in statistics gathering
Server-driven Alerts
Automatic Advisers
Auto-tuning to adapt to changing workload
Integration with the Enterprise Manager

37. Next Steps…. Recommended sessions
The Self-Managing Database : Automatic Health Monitoring (Thursday, Sept. 11, 11 AM)
Enterprise Manager : Scalable Oracle Management (Thursday, Sept. 11, 1 PM)
Recommended demos and/or hands-on labs
Oracle Database 10g : Manage the Oracle Environment Hands-On Lab
Campground Demo : “The Self-Managing Database: Space Management”
Relevant web sites to visit for more information

38. Reminder: Please complete the OracleWorld online session survey Session # 40170 Thank you.

39. Q
&
Q U E S T I O N S
A N S W E R S A