11g high availability

8/3/2019 11g High Availability

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Flashback Archive

Data Guard

Streams Online Maintenance

Data Recovery Advisor

High Availability


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Flashback Data Archive


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Data History and Retention

Data retention and change control requirementsare growing

Regulatory oversight and Compliance

Sarbanes-Oxley, HIPAA, Basel-II, Internal Audit

Business needs

Extract temporal dimension of data

Understand past behavior and manage customerrelationships profitably

Failure to maintain appropriate history & retentionis expensive

Legal risks

Loss of Reputation Current approaches to manage historical data are

inefficient and often ineffective


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Data History and Retention - Requirements

Historical data needs to be secure and tamper proof

Unauthorized users should not be able to accesshistorical data

No one should be able to update historical data

Easily accessible from existing applications

Seamless access Should not require special interfaces or application

changes

Minimal performance overhead

Optimal Storage footprint

Historical data volume can easily grow into hundreds ofterabytes

Easy to set up historical data capture and configureretention policies


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Managing Data History CurrentApproaches

Application or mid-tier level

Combines business logic and archive policies

Increases complexity

No centralized management

Data integrity issues if underlying data is updated directly

Database level Enabled using Triggers

Significant performance and maintenance overhead

External or Third-party

Mine redo logs

History stored in separate database Cannot seamlessly query OLTP and history data

None of the above approaches meet all customer requirements

Customers are therefore forced to make significant compromises


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Introducing Flashback Data Archive

Transparently tracks historical changes to all Oracledata in a highly secure and efficient manner

Historical data is stored in the database and can be retained foras long as you want

Special kernel optimizations to minimize performance

overhead of capturing historical data

Historical data is stored in compressed form to minimizestorage requirements

Automatically prevents end users from changing historical data

Seamless access to archived historical data Using AS OF SQL construct

select * from product_information AS OF TIMESTAMP

'02-MAY-05 12.00 AM where product_id = 3060


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Introducing Flashback Data Archive

Extremely easy to set up

enable history capture inminutes!

Completely transparent toapplications

Centralized and automaticmanagement

policy-based

multiple tables can share sameRetention and Purge policies

automatic purge of aged history

AutomaticallyPurge Databased onRetention policy

Retention Period


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How Does Flashback Data Archive Work?

Primary source for history is the undodata

History is stored in automaticallycreated history tables inside thearchive

Transactions and its undo records ontracked tables marked for archival

undo records not recycled until history isarchived

History is captured asynchronouslyby new background process (fbda)

default capture interval is 5 minutes capture interval is self-tuned based on

system activities

process tries to maximize undo data readsfrom buffer cache for better performance

INSERTs do not generate history records


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Flashback Data Archive And DDLs

Possible to add columns to tracked tables Automatically disallows any other DDL that

invalidates history Dropping and truncating a tables

Dropping or modifying a column Must disable archiving before performing any major

changes Disabling archiving discards already collected history

Flashback Data Archive guarantees historical data

capture and maintenance Any operations that invalidates history or prevents historical

capture will be disallowed


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Creating Flashback Data Archive &Enable History Tracking

1. Create tablespace (Automatic Segment SpaceManagement is required)

2. Create a flashback data archive

Set the retention period

3. Enable archiving on desired tables

CREATE FLASHBACK ARCHIVE fda1

TABLESPACE tbs1

RETENTION 5 YEAR;

ALTER TABLE EMPLOYEES FLASHBACK ARCHIVE fda1;


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Managing Flashback Data Archive

SYS_FBA_HIST_* - Internal History Table

replica of tracked table with additional timestamp columns

partitioned for faster performance

no modifications allowed to internal partitions

compression reduces disk space required

no out-of-box indexes

support for copying primary key indexes from tracked table in laterreleases (TBD)

Applications dont need to access internal tables directly

use AS OF to seamlessly query history

Alerts generated when flashback data archive is 90% full

Automatically purges historical data after expiration ofspecified retention period

supports ad-hoc purge by administrators (privileged operation


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Summary

Managing historical data should no longer be aonerous task

Flashback Data Archive provides a secure, efficient,easy to use and applicant transparent solution

Easy to implement

Centralized, Integrated and query-able

Highly storage and performance efficient

Automatic, Policy-based management

Reduce costs of compliance

Can be used for variety of other purposes

Auditing, Human error correction, etc.


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Data Guard


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Data Guard Enhancements

Better standby resource utilization

Enhanced HA / DR functionality

Improved performance

Data Guard becomes an integral part of IT operations


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Physical Standby withReal-Time Query

Physical StandbyDatabase

PrimaryDatabase

Continuous RedoShipment and Apply

ConcurrentReal-Time Query

Read-only queries on physical standby concurrent with redo apply Supports RAC on primary and/or standby Queries see transactionally consistent results

Handles all data types, but not as flexible as logical standby


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Real-time Query Benefits

Immediate appeal to a large installed customer base forphysical standby

Allows leveraging existing physical standby assets for excellentbusiness use

Satisfies several customers with specific requirements

Telecom service schedules for technicians Medical access patient medical reports

Finance provide management-level reports

Transportation provide responses to package tracking queries

Web-business scale-out read access for catalog browsing Significant differentiator compared to storage mirroring

Mirror volumes are offline during mirroring


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Updates

PrimaryDatabase

Queries


Snapshot StandbyLeverage Standby Database for Testing

Snapshot StandbyDatabase

UpdatesQueries


Preserves zero data loss, although no real time query or fast failover

Truly leverages DR hardware for multiple purposes

Similar to storage snapshots, but provides DR at the same time andusessingle copy of storage


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11.1

Standby

> alter database convert tosnapshot standby;

PERFORM TESTING, ARCHIVE LOGS CONTINUE TO BESHIPPED

> alter database convert to

physical standby;

Snapshot StandbyEasier than manual steps in 10.2

10.2Standby

> alter database recover managed standby database

cancel;

> create restore point before_lt guarantee flashback

database;

Primary

> alter system archive log current;

> alter system set log_archive_dest_state_2=defer;

Standby

> alter database activate standby database;

> startup mount force;

> alter database set standby database to maximize

performance;

> alter system set log_archive_dest_state_2=defer;

> alter database open;

PERFORM TESTING, ARCHIVE LOGS NOT SHIPPED


> flashback database to restore point before_lt;

> alter database convert to physical standby;


> alter database recover managed standby database

disconnect from session;

Primary

> Alter system set log_archive_dest_state_2=enable


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db_lost_write_protect

Use Physical Standby toDetect Lost Writes

Use new initialization parameter

Compare versions of blocks on the standby with that

in the incoming redo stream Version discrepancy implies lost writes

Can use the standby to failover and restore dataconsistency


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Enhanced SQL Apply

Support

XMLType data type (CLOB)

Transparent Data Encryption (TDE)

DBMS_FGA (Fine Grained Auditing)

DBMS_RLS (Virtual Private Database) Role-specific DBMS_SCHEDULER jobs

(PRIMARY, LOGICAL STANDBY, BOTH)

Dynamic SQL Apply parameter changes

Support for Parallel DDL execution on the standby database


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Enhanced Fast-Start Failover

Supports Maximum Performance (ASYNC) Mode

Automatic failover for long distance standby Data loss exposure limited using Broker property (default=30 seconds, min=6 seconds)

Immediate fast-start failover for user-configurable health conditions

Condition examples:

Datafile Offline

Corrupted Controlfile

Corrupted Dictionary

Inaccessible Logfile

Stuck Archiver Any explicit ORA-xyz error

Apps can request fast-start failover using api

ENABLE FAST_START FAILOVER [CONDITION ];

FastStartFailoverLagLimit

DBMS_DG.INITIATE_FS_FAILOVER


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Data GuardPerformance Improvements

Faster Failover Failover in seconds with Fast-Start Failover

Faster Redo Transport

Optimized async transport for Maximum Performance Mode

Redo Transport Compression for gap fetching: new compressionattribute for log_archive_dest_n

Faster Redo Apply

Parallel media recovery optimization

Faster SQL Apply

Internal optimizations

Fast incremental backup on physical standby database

Support for block change tracking


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Rolling Database UpgradesUsing Transient Logical Standby

Start rolling database upgrades withphysical standbys

Temporarily convert physical standby tological to perform the upgrade

Data type restrictions are limited to short upgradewindow

No need for separate logical standby forupgrade

Also possible in 10.2 (more manual steps)

Physical

Logical

Upgrade

Physical

Leverage your physical standbys!


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Streams


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Apply1Capture

Apply2

Streams Overview

RedoLogs

Non-OracleDatabase

All sites active and updateable

Automatic conflict detection & optional resolution Supports data transformations

Flexible configurations n-way, hub & spoke,

Database platform / release / schema structure can differ

Provides HA for applications where update conflicts can be avoided or managed

TransparentGateway

Propagate

Target

Database

Source

Database


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Streams Enhancements inOracle Database 11g

Additional Data Type Support

Table data comparison

Synchronous capture

Manageability & Diagnosibility improvements Performance improvements

Streams AQ Enhancements


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Newly Supported Datatypes

XMLType

Storage CLOB

Transparent Data Encryption (TDE)

Default: Capture TDE=> Apply TDE PRESERVE_ENCRYPTION apply parameter controls behaviour

when destination columns are not encrypted


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Table Data Comparison

Compare data between live sources

Compare 11.1 with 10.1, 10.2 or 11.1

Recheck

In-flight data

Rows that are different

Converge feature

Identify truth database (local or remote)

for row diffs

Compare

DBMS_COMPARISON


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Synchronous Capture

Available in all editions of Oracle Database 11g Efficient internal mechanism to immediately capture

change

Changes captured as part of the user transaction

DML only LCRs enqueued persistently to disk

When to use:

Replicate a few low activity tables of highly active sourcedatabase

Capture from redo logs cannot be implemented

DBMS_CAPTURE_ADM.CREATE_SYNC_CAPTURE


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Streams Performance Advisor

Auto-discovery of streams topology on

multiple databases Automatic performance analysis

across all databases

Per-Stream Analysis:

Time-based analysis of each component(waits, CPU, etc.) using ASH

Bottleneck components Top wait events of bottleneck

Per-Component Analysis:

Throughput and latency

Aborted or Enabled

Integrated with ADDM

Stream errors are integrated withServer-generated Alerts

Change Apply

101100001110101

Capture Changes


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Split and Merge of Streams

Challenge With hub&spoke configurations, when one destination is

unavailable, all destinations are hit with a performance impactbecause capture queue spills to disk after 5 minutes

Solution Split the queue between live and down destinations

Merge queues after recovery

Maintains high performance for all replicas Automated, fast catch-up for unavailable replica


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Streams: Hub with 3 Spokes

DestinationDatabase A

ApplyProcess

Queue

DequeueLCRs

Destination

Database B

ApplyProcess

Queue

DequeueLCRs

ApplyProcess

DestinationDatabase C

Queue

DequeueLCRs

Queue

EnqueueLCRs

CaptureProcess

Propagation B

Propagation A

Propagation C

Source Database


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Apply

Process

Queue

DequeueLCRs

DestinationDatabase B

ApplyProcess

Queue

DequeueLCRs


Queue

DequeueLCRs

Queue

EnqueueLCRs

CaptureProcess

Propagation B

CLONEDPropagation A

Propagation C

Source Database

XQueue

CLONED CaptureProcess (Disabled)

Split Streams: Site A Unavailable

ApplyProcess


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Split Streams: Site A Available

ApplyProcess


Apply

Process

Queue

DequeueLCRs

DestinationDatabase B

ApplyProcess

Queue

DequeueLCRs


Queue

DequeueLCRs

Queue

EnqueueLCRs

CaptureProcess

Propagation B

CLONEDPropagation A

Propagation C

Source Database

Queue

CLONED CaptureProcess (Enabled)

EnqueueLCRs


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St


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Streams. more manageability improvements

Automated Alerts

abort of capture, propagation, or apply

1st error in DBA_APPLY_ERROR

Propagation uses scheduler

Improved error messages

ORA-1403 -> ORA-26786 or ORA-26787 customer DML Handlers need to handle these new exceptions

more detail added to many error messages

Cross-database LCR tracking trace Streams messages from start to finish

DBMS_CAPTURE_ADM.SET_MESSAGE_TRACKING(mylabel)

V$STREAMS_MESSAGE_TRACKING


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Streams performance

CERN reporting >5000 txns/s in 10.2.03

OpenLAB presentation

http://openlab-mu-internal.web.cern.ch/openlab-mu-internal/Documents/3_Presentations/Slides/2007/DW_openlab_qr1_2007.pdf

11g performance improvements

common case 10.2 -> 11.1 almost double


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Streams Advanced Queuing (AQ)New Features

JMS/AQ performance improvements

Direct Streams AQ support in JDBC

Scalable event notification

Grouping notification by time

Multiple processes notification for scalability

Improved Manageability

Scheduler support

Performance views


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Flashback Transaction


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Flashback Transaction

Automatically finds and backs out a transaction and allits dependent transactions

Utilizes undo, archived redo logs, supplemental logging

Finalize changes with commit, or roll back

Dependent transactions include Write after write

Primary Key insert after delete

Faster, Easier than laborious manual approach

DBMS_FLASHBACK.TRANSACTION_BACKOUT


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Flashback TransactionEnterprise Manager Support


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D R Ad i


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Time to Repair

Data Recovery AdvisorThe Motivation

Oracle provides robust tools for datarepair:

RMAN physical media loss or corruptions

Flashback logical errors

Data Guard physical or logical problems

However, problem diagnosis andchoosing the right solution can be errorprone and time consuming

Errors more likely during emergencies

Recovery

Investigation& Planning


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Oracle Database tool that automatically diagnoses data failures,

presents repair options, and executes repairs at the user's request Determines failures based on symptoms

E.g. an open failed because datafiles f045.dbf and f003.dbf are missing

Failure Information recorded in diagnostic repository (ADR)

Flags problems before user discovers them, via automated health

monitoring Intelligently determines recovery strategies

Aggregates failures for efficient recovery

Presents only feasible recovery options

Indicates any data loss for each option

Can automatically perform selected recovery steps

Reduces downtime by eliminating confusion

D t R Ad i


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Data Recovery AdvisorEnterprise Manager Support

D R Ad i


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Data Recovery AdvisorRMAN Command Line Interface

lists all previously detected failures

presents recommended recovery options

repair database failures (defaults to first repair option from most recent

ADVISE FAILURE)

change failure priority (with exception of critical priority failures, e.g.

missing control file)

RMAN> list failure

RMAN> advise failure

RMAN> repair failure

RMAN> change failure 5 priority low


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Recovery Manager, UltraSafe Mode and Online

Operations


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RMAN Enhancements

Better performance

Intra-file parallel backup and restore of single data files (multi-sectionbackup)

Faster backup compression (ZLIB, ~40% faster)

Better security Virtual private catalog allows a consolidation of RMAN repositories and

maintains a separation of responsibilities.

Lower space consumption

Duplicate database or create standby database over the network, avoidingintermediate staging areas

Integration with Windows Volume Shadow Copy Services (VSS)API

Allows database to participate in snapshots coordinated by VSS-compliantbackup management tools and storage products

Database is automatically recovered upon snapshot restore via RMAN


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Ultra-Safe Mode

The DB_ULTRA_SAFE parameter provides an easy way toturn on the safest mode. It affects the default values of thefollowing parameters DB_BLOCK_CHECKING, which initiates checking of database blocks.

This check can often prevent memory and data corruption.

DB_BLOCK_CHECKSUM, which initiates the calculation and storage ofa checksum in the cache header of every data block when writing it todisk. Checksums assist in detecting corruption caused by underlyingdisks, storage systems or I/O systems.

DB_LOST_WRITE_PROTECT, which initiates checking for "lost writes".

Data block lost writes occur on a physical standby database, whenthe I/O subsystem signals the completion of a block write, which hasnot yet been completely written in persistent storage. Of course, thewrite operation has been completed on the primary database.

O li O i &


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Online Operations &Redefinition Improvements

Fast add column with default value

Invisible indexes speed application migration andtesting

Online index build with NO pause to DML

No recompilation of dependent objects when OnlineRedefinition does not logically affect objects

More resilient execution of table DDL operations

Support Online Redefinition for tables withMaterialized View Logs


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AQ&

Hi h A il bilit


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Flashback Archive

Data Guard

Streams Online Maintenance


High Availability


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