Data Guard SQL ApplyBack to the Future!

Larry M. CarpenterSenior Principal Consultant

Server Technologies

Oracle Corporation

Session id: 40144

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

• Maintains a ‘Physical’ block for block copy of the Primary Database

Physical Standby DatabaseAsynchronous/Synchronous

Redo Shipping

PrimaryDatabase

Network

DIGITAL DATA STORAGE

DIGITAL DATA STORAGE

Backup

Redo Apply

MRP

SQL Apply Architecture

Logical Standby Database

ContinuouslyOpen for Reports

SQLApply

TransformRedo to

SQLAdditional

Indexes and Materialized

Views

Asynchronous/Synchronous

Redo Shipping

NetworkNetwork

PrimaryDatabase

• Maintains a ‘Logical’ transactional copy of the Primary Database

SQL Apply Engine Architecture

Logical Standby Database

Remote Archived Logs

MiningGroup

ApplyingGroup

SQL

LSP

PX PX

RFS

PX PX

Log Transport Services

Redo

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

Users access only the standby outside the firewall.

Web Developers access only the Production DB.

Physical Standby provides extra Disaster Recovery

FireWall

Logical Standby

Physical StandbyProduction Database

Web Developers

Internet Users

Logical Standby

FireWall

Bank #1 – Online Banking

Users access the Production DB outside the firewall.

Query Users access only the Logical Standby

Physical Standby outside firewall provides Disaster Recovery

FireWall

Production Database

Physical Standby

Logical Standby

Reporting and Query

Users

Internet Users

Bank #2 – Branch Banking

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

Production Database

Physical Standby

Logical Standby

Reporting and Query

Users

Branch 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

On-LineBackup

Primary Database

Physical/Logical Standby Database

Create and Copy Logical Standby

Control File

Transport Service

Restore

1

2

3

4

Zero Down Time Instantiation

Recovery Activation

Change DBNAME and DBID

Logical Standby Database!

Start SQL Apply Services

5 6

7

8

Support for more Data

Primarydatabase

Logical standbydatabase

Index Organized

Tables

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;

An up-to-date Logical or Physical

StandbyDatabase

StandbyRedo Logs

Real Time Apply

Archived Redo Logs

Archived Redo Logs

PrimaryDatabase

Transactions

Online Redo Logs

Oracle N

etReal Time

Apply!

RFSLGWR

ARCH ARCH

LSPMRP

Existing Site Recovery Tradeoffs

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

Primary Database Standby DatabaseRedo

Shipment

DelayedApply

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

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

Real Time Apply

No Delay!

Real TimeReporting

Flashback Log

Flashback Log

Primary: No reinstantiation after failover!

RedoShipment

Primary Database Standby Database

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 ATTRIBUTES------------ ---------------------COUNTRIES Index Organized TableDEPARTMENTS Table CompressionEMPLOYEES Table CompressionJOBS Table CompressionJOB_HISTORY Table CompressionLOCATIONS Table CompressionREGIONS 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 ENABLE GUARD;

SQL> ALTER SESSION DISABLE 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

ALTER DATABASE START STANDBY APPLY SKIP FAILED TRANSACTION;

Logical StandbyDatabase

Redo from

primary Restart SQL

ApplySkip 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 DatabaseVersion X

Logical Standby

Version X

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

Node One Node Two

Upgrade the Logical Standby

Production DatabaseVersion X

Logical Standby

Version X+1

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.

Node One Node Two

Run In Mixed Environment

Production DatabaseVersion X

Logical Standby

Version X+1

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

Node One Node Two

Switch Over Applications

Logical Standby

Version X

Production Database

Version X+1

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.

Node One Node Two

Upgrade Node One

Logical Standby

Version X+1

Production Database

Version X+1

Upgrade the Logical Standby database on Node One.

Applications still running on Node Two, the Upgraded Production Database.

Node One Node Two

Re-Enable Redo Shipping

Logical Standby

Version X+1

Production Database

Version X+1

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

Node One Node Two

Switch Back to Original Setup

Production Database

Version X+1

Logical Standby

Version X+1

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

Node One Node Two

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 StepsHigh Availability Sessions from Oracle

11:00 AM

How Oracle Database 10g Revolutionizes Availability and

Enables the Grid

3:30 PM

Oracle Recovery Manager (RMAN) 10g: Reloaded

5:00 PM

Proven Techniques for Maximizing Availability

8:30 AM

Oracle Database 10g - RMAN and ATA Storage in Action

 

11:00 AM

Oracle Data Guard: Maximum Data Protection at Minimum Cost

 

1:00 PM

Oracle Database 10g Time Navigation: Human-Error Correction

 

4:30 PM

Data Guard SQL Apply: Back to the Future

Wednesday in Moscone Room 304Tuesday in Moscone Room 304

For More Info On Oracle HA Go To http://otn.oracle.com/deploy/availability/

Next StepsHigh Availability Sessions from Oracle

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

Thursday

For More Info On Oracle HA Go To http://otn.oracle.com/deploy/availability/

Real Application Clusters

Data Guard

Database Backup & Recovery

Flashback Recovery

LogMiner, Online Redefinition, and Cross Platform Transportable

Tablespaces

Database HA Demos All Four DaysIn The Oracle Demo Campground

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