Remote DBA Experts 11g Features

Oracle 11G New Features Prepared by: Brian Hays and Jeff Kondas

11G New Features
Flashback data archive
Database replay
SQL performance advisor
SQL plan management
Proactive health checking
Automatic diagnostic repository
Online patching
Patching advisor
Memory management
SQL Cache
SQL Access advisor (Partition)
Virtual columns
Invisible indexes
Transparent tablespace encryption
Create and rebuild indexes online

Flashback Data Archive
Flashback feature introduced in 9i
Allows viewing of data at a point in time in the past
System managed undo required
Undo data could be overwritten preventing flashback operations from occurring
10G introduced flashback database
Flash entire database back in time using flashback recovery logs

Flashback Data Archive
11G introduces Flashback Data Archive
Flashback operations now available over an extended period of time.
Able to specify retention during flashback tablespace creation.
Use Flashback Data Archive to Generate Reports, for Trending, to Recover Data, etc.
SELECT product_number, product_name, count FROM inventory AS OF TIMESTAMP TO_TIMESTAMP ('2007-01-01 00:00:00', 'YYYY-MM-DD HH24:MI:SS');
Use log miner GUI to search for specific changes.

Database Replay
Capture all database activity “like database DVR”.
Enables user to perform real-world testing
Capture actual database workload on production system and replay it for testing.
Test parameter, new release changes
Measure performance impact using diagnostic tools.

Database Replay Analyze this!

SQL Performance Analyzer
Compare performance of SQL statements before and after a system change.
Common Usage Scenarios:
Upgrade
Parameter Changes
Schema Changes (Indexes)
Optimizer Statistics
Produce report identifying changes in execution plans or performance of SQL statements.
Measures overall response time of every individual SQL statement in the workload.
Reveals regressed SQL statements (allowing time to remedy the problem.)
Offers significant advantage for database tuning.
I KNEW I shouldn’t have reduced the SGA...

SQL Performance Analyzer Observe how system change will affect each SQL statement in tuning set Observe overall affect from system change

SQL Plan Management
Preventative tool to track SQL statements access paths.
Stored in SQL Plan Baseline.
If access path changes, new plan is stored.
Database evaluates performance of new plans and integrates plans with better performance into SQL Plan Baselines to be accepted or removed.
Prevents bad access paths from being implemented.
Provide administrators time to evaluate the access path change.
Interface available to view history of plans.

SQL Plan Management Baselines Review captured access paths Analyze each path

Proactive Health Checking
Redo integrity
Undo integrity
Transaction integrity
Dictionary integrity
Validate database
Recovery Advisor Automatic Monitors

Proactive Health Checking
“ Checkers” results recorded in repository called Automatic Diagnostic Repository.
Redo Integrity Check - scans contents of redo and archive logs for accessibility and corruption
Undo Segment Integrity Check - finds logical undo corruptions
Transaction Integrity Check - similar to Undo Segment Check except that it checks only one specific transaction
Dictionary Integrity Check - examines the integrity of core dictionary objects
DB Structure Integrity Check - verifies integrity of database files and reports failures if files are inaccessible, corrupt, inconsistent
Data Block Integrity Check - detects disk image block corruptions

Identify and Resolve Critical Database Issues
When “checkers” find a problem, information is reported and then fed to recovery advisors.
New Incident Packaging Service creates a bundle of all issues and supporting files for easy reporting to Oracle Support.
Reduce time to problem resolution.

Proactive Health Checking Data Recover Advisor – Auto Recovery Script Generation

Automatic Diagnostic Repository
Combine incidents into " envelope "
All relevant trace files associated with error are identified and added to the package and sent to Oracle Support.
Reduce time to problem resolution.

Online Patching
In Oracle Database 11 g , most patches, specifically diagnostic patches, can now be applied online without taking any downtime.
Reduce planned as well as unplanned downtime.

Patch Advisor
Setup Metalink credentials in Enterprise Manager and all patches will be automatically downloaded during a patching session.
Gathers information on available patches based on the features you are using and downloads recommended patches.

Patch Advisor Determine if there are patches available only for features you are using. See available CPU patches.

Memory Management
Oracle 9i introduces automatic memory management
MAX_SGA_SIZE , swaps memory between shared pool and data buffer cache
Oracle 10g simplifies memory management
SGA_TARGET , allocates specified value for the overall SGA memory area.
Memory area PGA is entirely outside the SGA, so is not touched by the Automatic SGA Management feature
Oracle 11g SGA & PGA one setting
MEMORY_TARGET , boundary between PGA and SGA are fluid and the memory allowed to flow freely between them
Avoids wasted memory due to incorrect memory pool settings.

Memory Management MEMORY_TARGET One setting Memory Advisor

SQL Access Advisor
SQL Access Advisor has been enhanced
Helps achieve performance goals by recommending proper set of materialized views, partitions, indexes ,etc.
Analysis includes considering cost of creation and maintaining access structures.
Using these structures is essential when optimizing SQL and can result in significant performance improvements.
Recommendations on improving schema design
Partitioning , indexing, and creating materialized views based on actual frequency and type of usage.

SQL Access Advisor Considers cost of creation and maintaining access structures Advise on complex structures

SQL Result Cache
Cache in SGA, like buffer cache or PGA
Accessing memory is far quicker than accessing hard drives
When queries and functions are executed repeatedly, results are retrieved directly from cache memory
Results in faster response time
Execute with hint result_cache
Stores results of SQL queries and PL/SQL functions in area called Result Cache Memory
Allows lookup, rather than recalculation.
A change in the underlying table invalidates the cache, resulting in dynamic refresh next time it is queried.

Virtual Columns
Enable application developers to define computations and transformations as column definition of tables without space consumption
Offers the flexibility to add columns that convey business sense without adding any complexity to code or performance impact.
SQL> create table sales
2 (
3 sales_id number,
4 cust_id number,
5 sales_amt number,
6 sale_category varchar2(6)
7 generated always as
8 (
9 case
10 when sales_amt <= 10000 then 'LOW'
11 when sales_amt > 10000 and sales_amt <= 100000 then 'MEDIUM'
12 when sales_amt > 100000 and sales_amt <= 1000000 then 'HIGH'
13 else 'ULTRA'
14 end
15 ) virtual

Invisible Indexes
Is this index really beneficial?
Oracle 11g offers option to make indexes invisible to optimizer.
alter index employee invisible;
Analyze impact index is having on system without affecting performance.
Great for testing.

Transparent Tablespace Encryption
Transparent Data Encryption (10g R2)
Performance is an issue with this feature. Index range scan cannot be applied to encrypted columns.
Transparent Tablespace Encryption (11g)
All data in the tablespace is encrypted.
Index scanning occurs in memory where the data is unencrypted, causing no performance impact.

Create and Rebuild Index Online
The online clause rebuilds the index without affecting the DML.
In 10g the operation required an exclusive lock at the end of the process and DMLs had to wait. Caused concurrency waits.
In Oracle Database 11 g , the online rebuild is truly online, does not hold exclusive lock and DMLs are not affected.
Maintain indexes without affecting system performance.

References
The Top New Features for DBAs and Developers ; Arup Nanda ; Oracle Press
www.oracle.com , technet.oracle.com
All companies and product names are trademarks or registered trademarks of the respective owners.
All Oracle11g Documentation

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Remote DBA Experts 11g Features

by Remote DBA Experts on Aug 03, 2009

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Remote DBA Experts 11g Features — Presentation Transcript