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Session id: 40144
Data Guard SQL Apply
Back to the Future!
Larry M. Carpenter
Senior Principal Consultant
Server Technologies
Oracle Corporation
A Quick Review
 What’s in the Oracle Data Guard ‘Stack’?
 A High Level Overview
–
–
Redo Apply
SQL Apply
 How does SQL Apply do it today?
 A Couple of Customer Case Studies
–
–
–
How they use Oracle Data Guard Today.
What Business Problems they solved.
What can we do to make it better?
At the Highest Level
 Data Guard comprises of two parts
–
REDO APPLY
 Maintains a physical, block for block copy of the
Production (also called Primary) database.
–
SQL APPLY
 Maintains a logical, transaction for transaction
copy of the Production database.
REDO Apply Architecture
Primary
Database
Asynchronous/
Synchronous
Redo Shipping
Physical Standby Database
MRP
Redo
Apply
Network
Backup
DIGITAL DATA STORAGE
DIGITAL DATA STORAGE
• Maintains a ‘Physical’ block for block copy of the Primary Database
SQL Apply Architecture
Primary
Database
Network
Logical Standby Database
Continuously
Open for Reports
Asynchronous/
Synchronous
Redo Shipping
SQL
Apply
Transform
Redo to
SQL
Additional
Indexes and
Materialized
Views
• Maintains a ‘Logical’ transactional copy of the Primary Database
SQL Apply Engine Architecture
Mining
Group
PX
PX
Redo
LSP
Applying
Group
PX
PX
SQL
RFS
Log
Transport
Services
Remote Archived Logs
Logical Standby
Database
Customer Case Studies
 How are customers using SQL Apply today?
–
–
A look at two European Banks and their setup
What Problems were they able to solve?
 What are we doing to make life easier and
better?
–
–
–
For the Business
For the User
For the DBA!
Bank #1 –Web Site
Internet Users
FireWall
Logical
Standby
Logical
Standby
FireWall



Users access only
the standby
outside the
firewall.
Web Developers
access only the
Production DB.
Physical Standby
provides extra
Disaster
Recovery
Web
Developers
Production Database
Physical Standby
Bank #1 – Online Banking
Internet Users
Production
Database
Physical
Standby
FireWall



Users access the
Production DB
outside the firewall.
Query Users access
only the Logical
Standby
Physical Standby
outside firewall
provides Disaster
Recovery
Reporting
and Query
Users
Logical Standby
Bank #2 – Branch Banking
Branch Users
Production
Database




Branch Users access
the Production DB.
Query Users access
only the Logical
Standby
Physical Standby
Disaster Recovery
Production Database
and Logical standby on
the same server
Logical
Standby
Physical
Standby
Reporting
and Query
Users
Oracle Database 10g
Solving Those Problems!
 Zero Downtime Logical Standby Database
Creation
–
Faster, Easier, Bulletproof
 Support for more Data Types
–




Wider range of applications and functionality
supported by SQL Apply
Real Time Apply
Integration with Flash Back Database
Improved Ease of Use
Rolling Database Upgrades – Going Forward
Zero Downtime Instantiation
 Logical standby databases easy to create
–
–
–
–
Using an On-line backup!
No shut down and no quiesce of the Primary
No shutdown = no downtime of production system
No quiesce = no wait on quiesce
 And no dependence on Resource Manager
Zero Down Time Instantiation
1
3
On-Line
Backup
2
Primary
Database
Restore
Create and Copy
Logical Standby
Control File
4
Transport Service
Physical/Logical
Standby Database
Zero Down Time Instantiation
5
6
Recovery
Activation
7
Change DBNAME and DBID
8
Start SQL Apply Services
Logical Standby
Database!
Support for more Data
Index
Organized
Tables
Primary
database
Logical standby
database
More
datatypes
Data Types
 New Support for:
–
–
–
–
–
–
LONG
LONG_RAW
Multi-byte CLOB
NCLOB
BINARY_FLOAT (New in Oracle Database 10g)
BINARY_DOUBLE (New in Oracle Database 10g)
Index Only Tables
 IOT Support in a Logical standby database
–
–
No LOB columns in the IOT
No IOT with Overflow
Real Time Apply
 Redo data is applied to the standby database as
it is received from the primary database.
–
Apply services on the standby do not wait until the
current standby redo log file is archived.
 Invoked through SQL:
–
For SQL Apply:
 ALTER DATABASE START LOGICAL STANDBY APPLY
IMMEDIATE;
–
For Redo Apply:
 ALTER DATABASE RECOVER MANAGED STANDBY DATABASE
USING CURRENT LOGFILE;
Real Time Apply
Oracle Net
Transactions
LGWR
ARCH
LSP
MRP
RFS
Online
Redo Logs
Primary
Database
Archived
Redo Logs
An up-to-date
Logical or Physical
Standby
Database
Standby
Redo
Logs
ARCH
Real
Time
Apply!
Archived
Redo Logs
Existing Site Recovery Tradeoffs
Primary Database
Standby Database
Redo
Shipment
Delayed
Apply
 Log apply may be delayed to protect from user errors but:
– Switchover/Failover gets delayed
– Reports run on old data
 After failing over to standby, production DB must be rebuilt
Reporting on
delayed data
Flashback Database
 A new strategy for point in time recovery
 Eliminate the need to restore a whole
database backup
 Integrated seamlessly with RMAN
–
–
Think of it as a continuous backup
Restores just changed blocks
 It’s fast - recover in minutes, not hours
 It’s easy - single command restore
RMAN> FLASHBACK DATABASE
TIMESTAMP to_timestamp
('2003-08-15 16:00:00',
'YYYY-MM-DD HH24:MI:SS');
Enhanced DR with Flashback Database
Primary Database
Redo
Shipment
Real Time
Apply
Standby Database
Real Time
Reporting
No Delay!
Flashback
Log
Flashback
Log
Primary: No reinstantiation
after failover!



Flashback DB removes the need to delay application of logs
Flashback DB removes the need to reinstantiate primary after failover
Real-time apply enables real-time reporting on standby
Ease of Use
 New and Improved Data Guard Manager!
 Monitoring SQL Apply
–
–
Unsupported Storage Attributes
Applied Logs and Apply Progress
 Managing the Logical Standby
–
–
–
Bypassing the Guard
Skipping Table Redo
Skipping Failed (and subsequently fixed)
Transactions
Enterprise Manager New Features
 Streamlined browser-based interface that
enables complete standby database lifecycle
management
 Focus on:
–
–
–
Ease of use
Management based on best practices
Pre-built integration with other HA features
Viewing Unsupported Objects
SQL> SELECT DISTINCT table_name, attributes
2> FROM dba_logstdby_unsupported
3> WHERE owner = 'HR';
TABLE_NAME
-----------COUNTRIES
DEPARTMENTS
EMPLOYEES
JOBS
JOB_HISTORY
LOCATIONS
REGIONS
ATTRIBUTES
--------------------Index Organized Table
Table Compression
Table Compression
Table Compression
Table Compression
Table Compression
Table Compression
7 rows selected.
Checking for Applied Logs
SQL> SELECT thread#, sequence#, applied FROM
2> dba_logstdby_log order by sequence#;
THREAD# SEQUENCE# APPLIED
---------- ---------- ------1
48 YES
1
49 CURRENT
1
50 CURRENT
1
51 CURRENT
1
52 CURRENT
1
53 CURRENT
6 rows selected.
Viewing the Progress of SQL
Apply
SQL> SELECT applied_scn, applied_thread#, newest_scn,
2> newest_thread#
3> FROM dba_logstdby_progress;
APPLIED_SCN APPLIED_THREAD# NEWEST_SCN NEWEST_THREAD#
----------- --------------- ---------- -------------961263
1
961263
1
New Guard Bypass Syntax
SQL> ALTER SESSION DISABLE GUARD;
SQL> ALTER SESSION ENABLE GUARD;
Using Wildcards to Skip
Tables
DBMS_LOGSTDBY.SKIP(stmt, schema_name, table_name,
proc_name, use_like, esc);
 In Oracle9i Database all names are wildcard
matched.
–
TEST_T% for table_name skips all tables starting with TEST
and with anything in the place of the ‘_’.
 No way to indicate that you only wanted table TEST_TABLE
and not TEST1TABLE.
 Set use_like to False to use the escape character.
 Set esc to a \ for example to allow better matching
–
Now TEST\_T% will only skip TEST_TABLE.
Automatically Skipping the
Last Failed Transaction
Logical
Standby
Database
Redo
from
primary
Skip Failed
transaction
Restart
SQL
Apply
ALTER DATABASE START STANDBY APPLY
SKIP FAILED TRANSACTION;
Remember Those Banks?
 Logical Standby Creation simple, fast and online!
 Logical standbys no longer have to lag an archive
log behind the Primary!
 More Data types = More Applications!
 Better View of the Logical Standby Status!
 Easier to Manage!
Rolling Database Upgrades
 In Oracle Database 10g, SQL Apply provides
the starting point for performing rolling
upgrades of the Oracle RDBMS software and
database with minimal interruption of service.
 By utilizing a Logical standby database
customers can upgrade one database while
running on the original production database
and then run in a mixed version environment
before returning to the original, but upgraded,
configuration!
Those Banks (Again)?
Production
Database
Version X
Logical
Standby
Version X
Node One
Node Two



Initial Data Guard Setup with all
databases at Version X
Applications running on Node One,
the Production Database.
Reporting and Query Applications
running on the Logical standby
Upgrade the Logical Standby
Production
Database
Version X
Logical
Standby
Version X+1
Node One
Node Two





Stop Redo shipping to the Logical Standby
on Node Two.
Archive logs stack up on Node One.
Upgrade Logical Standby
Test General reporting and queries on the
upgraded logical standby
Applications still running on Node One, the
Production Database.
Run In Mixed Environment
Production
Database
Version X
Logical
Standby
Version X+1
Node One
Node Two




Re-enable Redo Shipping to the Logical
Standby on Node Two
Stacked Archive logs automatically sent to
resynchronize the Logical Standby (Bring it
up to date)
Applications still running on Node One, the
Production Database.
Reporting and Query Applications running
on upgraded Logical standby
Switch Over Applications
Logical
Standby
Version X
Production
Database
Version X+1
Node One
Node Two





Switch over databases from Node One to
Node Two.
Original Production Database is now a
Logical Standby.
Redo Shipping to Node One is stopped.
Archive logs stack up on Node Two.
Applications running on Node Two, the
Upgraded Production Database.
Upgrade Node One
Logical
Standby
Version X+1
Production
Database
Version X+1
Node One
Node Two


Upgrade the Logical Standby database on
Node One.
Applications still running on Node Two, the
Upgraded Production Database.
Re-Enable Redo Shipping
Logical
Standby
Version X+1
Production
Database
Version X+1
Node One
Node Two




Re-enable Redo Shipping to the
Logical Standby on Node One
Stacked Archive logs automatically
sent to resynchronize the Logical
Standby (Bring it up to date)
Applications still running on Node
Two, the Production Database.
Reporting and Query Applications
running on upgraded Logical
standby
Switch Back to Original Setup
Production
Database
Version X+1
Logical
Standby
Version X+1
Node One
Node Two



Initial Data Guard Setup with all
databases at Version X+1
Applications running on Node One,
the Production Database.
Reporting and Query Applications
running on the Logical standby
SQL Apply and
Oracle Database 10g
 Improving upon a great foundation!
–
–
–
–
Creating Logical Standby databases is a snap!
Querying up-to-date data with Real-Time Apply!
Supporting more and more Applications!
Moving forward to Rolling Upgrades!
Resources
 Maximum Availability Architecture white papers:
http://otn.oracle.com/deploy/availability/htdocs/maa.html
–
New SQL Apply Best Practices Paper now available!
 HA Portal on OTN: http://otn.oracle.com/deploy/availability
 Data Guard home page on OTN:
http://otn.oracle.com/deploy/availability/htdocs/odg_overview.html
 Oracle Consulting Services: http://otn.oracle.com/consulting
Next Steps
High Availability Sessions from Oracle
Tuesday in Moscone Room 304
Wednesday in Moscone Room 304
11:00 AM
8:30 AM
How Oracle Database 10g
Revolutionizes Availability and
Enables the Grid
Oracle Database 10g - RMAN and ATA
Storage in Action
11:00 AM
3:30 PM
Oracle Recovery Manager (RMAN)
10g: Reloaded
Oracle Data Guard: Maximum Data
Protection at Minimum Cost
1:00 PM
5:00 PM
Proven Techniques for Maximizing
Availability
Oracle Database 10g Time Navigation:
Human-Error Correction
4:30 PM
Data Guard SQL Apply: Back to the
Future
For More Info On Oracle HA Go To http://otn.oracle.com/deploy/availability/
Next Steps
High Availability Sessions from Oracle
Thursday
Database HA Demos All Four Days
In The Oracle Demo Campground
8:30 AM in Moscone Room 304
Oracle Database 10g Data
Warehouse Backup and Recovery:
Automatic, Simple, Reliable
8:30 AM in Moscone Room 104
Building RAC Clusters over
InfiniBand
Real Application Clusters
Data Guard
Database Backup & Recovery
Flashback Recovery
LogMiner, Online Redefinition, and
Cross Platform Transportable
Tablespaces
For More Info On Oracle HA Go To http://otn.oracle.com/deploy/availability/
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