Flashback operations allow recovering data from earlier points in time using undo and redo information. The Flash Recovery Area (FRA) stores files needed for flashback and recovery operations. Configuring the FRA involves specifying its size and location using parameters like DB_RECOVERY_FILE_DEST_SIZE and DB_RECOVERY_FILE_DEST. Flashback features like Flashback Query, Flashback Versions Query, and Flashback Database use information in the FRA to access earlier states of data.
Oracle Flashback technology provides several fast recovery options including Flashback Query, Flashback Version, Flashback Transaction, Flashback Table, and Flashback Drop. These features allow recovering data to a prior state by undoing changes or retrieving dropped objects without fully restoring backups. Flashback options can recover from corruptions, errors, disasters, and restore lost data through interfaces like easy-to-use Flashback commands.
Oracle Database 12c includes many new features across SQL, PL/SQL, database management, partitioning, patching, compression, Data Guard, and pluggable databases. Key features include increased datatype size limits, identity columns, implicit result sets in PL/SQL, adaptive plans, row pattern matching, pluggable databases that can be plugged into and unplugged from container databases, and many enhancements to compression, partitioning, Data Guard, and patching functionality.
This document summarizes new features in Oracle Database 12c Release 2. It outlines features for developers, administrators, SQL*Plus, conversion functions, and more. Key points include increased identifier length, new SQL*Plus features like history and prefetch settings, conversion functions, multi-tenant container database improvements, and performance enhancements like adaptive statistics and optimization.
Flashback technologies in Oracle allow users to view and recover data from the past. Flashback query allows querying past data by specifying a timestamp. Flashback table recovers an entire table to a time in the past without rolling back transactions. Flashback database recovers the entire database to a past time point using undo data and requires enabling flashback mode and setting up a flash recovery area.
OOW16 - Oracle Database 12c - The Best Oracle Database 12c New Features for D...Alex Zaballa
This document provides an overview of new features in Oracle Database 12c for developers and DBAs. It begins with an introduction by Alex Zaballa and then covers several new features including native support for JSON, data redaction, row limits and offsets for SQL queries, PL/SQL functions callable from SQL, session level sequences, and temporary undo. The document includes demonstrations of many of these new features.
This document provides an overview of Oracle performance tuning. It discusses Oracle architecture including processes, wait events, dynamic views, and tools for performance analysis like Statspack, AWR, Enterprise Manager, SQL tracing and tuning. Key aspects of performance tuning covered include statistics, hints, query rewrite, indexing, and application-level tuning for OLTP workloads.
Oracle Architecture document discusses:
1. The cost of an Oracle Enterprise Edition license is $47,500 per processor.
2. It provides an overview of key Oracle components like the instance, database, listener and cost based optimizer.
3. It demonstrates how to start an Oracle instance, check active processes, mount and open a database, and query it locally and remotely after starting the listener.
New Features for Database Administrator of Oracle 12c Database. Here are some of excellent Oracle 12c new features with examples for learning purpose. SQL,Backup and recovery, Database management, Oracle RAC, Oracle ASM included.
Oracle Flashback Query allows users to recover data to a previous point in time using the System Change Number (SCN) or timestamp. Setting up Flashback Query involves determining the undo retention period, creating an undo tablespace, and granting privileges to users. The DBMS_FLASHBACK package implements Flashback Query procedures like ENABLE_AT_TIME and DISABLE. DBMS_RESUMABLE allows long-running operations to suspend and resume if errors occur. The AFTER SUSPEND trigger notifies DBAs of suspended operations. Export/Import now supports Flashback Query parameters and resuming space allocation operations.
The document discusses Oracle database architecture including the relationship between Oracle software, operating system resources like CPUs, memory and disks, Oracle processes like background processes and server processes, and database structures like the system global area (SGA), program global area (PGA), control files, redo logs and data files. It also covers Oracle memory management, instance startup/shutdown, and basic database administration tasks.
The document provides an overview of Oracle Database locking mechanisms. It discusses the different types of locks used in Oracle including row-level locks, table-level locks, and different lock modes. It describes how Oracle uses row-level locking to allow non-blocking queries and read consistency. The document also covers advanced locking scenarios like deadlocks and blocked inserts. It concludes with demonstrating how to monitor locks using Oracle dictionary views and tools to identify blocked sessions.
OTN TOUR 2016 - DBA Commands and Concepts That Every Developer Should KnowAlex Zaballa
This document contains a summary of an Oracle DBA presentation on DBA commands and concepts that every developer should know. The presentation covered topics such as parallel queries, row chaining, explain plans, flashback queries, pending statistics, bulk processing, virtual private databases, extended data types, identity columns, and online table redefinition. It provided examples and demonstrations of many of these commands and concepts.
The document provides an overview of Oracle 10g database architecture including its physical and logical structures as well as processes. Physically, a database consists of datafiles, redo logs, and control files. Logically, it is divided into tablespaces containing schemas, segments, and other objects. The Oracle instance comprises the system global area (SGA) shared memory and background processes that manage tasks like writing redo logs and checkpointing data blocks. User processes connect to the database through sessions allocated in the program global area.
This presentation explains all of the new features that are relevant for developers in Oracle 12c. It's been out for a couple of years, but many companies haven't updated to 12c. So, if you're looking to update soon, or are just interested in what the new features are, look at this presentation.
The full post is available at http://www.completeitprofessional.com/oracle-12c-new-features-for-developers
Geek Sync I Need for Speed: In-Memory Databases in Oracle and SQL ServerIDERA Software
You can watch the replay for this Geek Sync webcast in the IDERA Resource Center: http://ow.ly/S6MG50A5ok5
Microsoft introduced IN-MEMORY OLTP, widely referred to as “Hekaton” in SQL Server 2014. Hekaton allows for the creation of fully transactionally consistent memory-resident tables designed for high concurrency and no blocking. With SQL 2016, many of the original restrictions and limitations of this feature have been reduced. IDERA’s Vicky Harp will give an overview of this feature, including how to compile T-SQL code into machine code for an even greater performance boost.
There’s also been a lot of buzz about Oracle 12c’s new IN-MEMORY COLUMN STORE. Oracle ACE Bert Scalzo will cover this new feature, how it works, it’s benefits, scripts to measure/monitor it and more. He will also touch on performance observations from benchmarking this new feature against more traditional SGA memory allocations plus Oracle 11g R2’s Database Smart Flash Cache. All findings, scripts and conclusions from this exercise will be shared. In addition, two very popular database benchmarking tools will be highlighted.
The document provides an overview of performance management tools in Oracle 12c, including the Cost Based Optimizer, SQL profiles, Oracle SQL Plan Management (SPM), and Oracle Real Time Monitoring. It discusses how to set up and use these tools to capture and evolve SQL execution plans to stabilize performance. Key topics include creating SQL profiles using the SQL Tuning Advisor or custom scripts, configuring SPM for plan capture and evolution, and managing plan retention and SQL Management Base space.
1) Oracle 10g introduces flashback query which allows users to query past states of data within a specified time period by accessing the undo logs.
2) Flashback table allows users to recover accidentally dropped tables from the recycle bin.
3) Rollback monitoring provides estimated time to complete long running transactions such as rollbacks.
Francisco Munoz Alvarez will present on advanced RMAN backup and recovery techniques. Key topics include point-in-time recovery using RMAN, RMAN and Oracle Flashback technologies, performance tuning RMAN operations, and database duplication. The presentation will provide examples of using RMAN for incomplete database recovery at a specific point in time, system change number, or log sequence number.
This document provides an overview of SQL tuning concepts and tools in Oracle Database. It discusses the differences between database tuning and SQL tuning. It also covers diagnostic tools like SQL Trace, ASH, EXPLAIN PLAN, AUTOTRACE, and SQL Developer. Active monitoring tools like AWR, SQL Monitor and reactive tools like SQL Diagnostic Tool and SQLD360 are also mentioned. Additional topics include full table scans, adaptive features, statistics, hints, pending statistics, restoring statistics history, and invisible indexes.
LVOUG meetup #4 - Case Study 10g to 11gMaris Elsins
My presentation on a case study of 10g to 11g upgrade at LVOUG meetup #4 in 2012. Includes preserving execution plans by exporting them from 10g and importing as SQL Plan Baselines in 11gR2
Oracle SQL Tuning 101 provides an overview of SQL tuning concepts and tools in Oracle Database. It discusses database tuning versus SQL tuning, proactive versus reactive tuning approaches, tools for SQL tracing and monitoring like SQL Trace, ASH, Autotrace, and SQL Monitor. The document also covers topics like full table scans, adaptive optimization features, pending statistics, and restoring or exporting statistics.
- The document discusses various Oracle Database backup and flashback technologies including native backups to object storage, flashback query, flashback version query, flashback transaction query, DBMS_FLASHBACK package, flashback data archive, flashback table, flashback drop, and flashback database.
- It provides an overview of the requirements and examples for using each technology. It also includes a table comparing the availability of different flashback features across various Oracle Database editions.
- The document concludes with some best practices for backups and flashback as well as distinguishing flashback from database point-in-time recovery (DBPITR).
Time is of the essence - The Fourth Dimension in Oracle Database 12c (on Flas...Lucas Jellema
Time has always been an important dimension for data in any database with topics like when was data created, when are records valid, how did records evolve over time, can we compare with yesteryear or even travel through time and data. The Oracle Database 12c release added a number of features in this area of time and history. The powerful Flashback mechanism is enhanced in many ways, such as to allow history to be constructed, for example from existing journaling tables and to capture the transaction context as well as the data change. Now for the first time, Flashback (Query & Data Archive) will become a key element in database design and application implementation.
The support for Valid Time Modeling (aka Temporal Database) makes the database aware of the fact that records have a business lifetime with start and expiry date. This awareness results in many new features that will be discussed and demonstrated.
Slides from the Singapore Oracle Sessions presentation on July 13th 2015, sponsored by the Oracle ACE Program and organized by Doug Burns.
Optimizing applications and database performanceInam Bukhary
This document discusses various ways to optimize application and database performance, including:
1. Optimizing database design, application design, memory usage, I/O, and reducing database contention.
2. Specific techniques mentioned include de-normalization, materialized views, bind variables, partitioning, parallel execution, and optimizing storage structures.
3. Monitoring tools are also discussed to detect issues like lock and latch contention that could be optimized.
Flashback technology allows users to view and recover data to previous points in time. The document discusses several Flashback features: Flashback Query lets users view data as of a past time; Flashback Version Query shows row versions between times; Flashback Table recovers an entire table; and Flashback Transaction backs out changes from a problematic transaction. The document provides examples and considerations for using each Flashback feature.
The document summarizes new features in Oracle Database 12c from Oracle 11g that would help a DBA currently using 11g. It lists and briefly describes features such as the READ privilege, temporary undo, online data file move, DDL logging, and many others. The objectives are to make the DBA aware of useful 12c features when working with a 12c database and to discuss each feature at a high level within 90 seconds.
Upgrading to Oracle 11g from previous versions requires consideration of changes to default parameter values, new features like Automatic Memory Management and SQL Plan Management, potential plan instability issues, and testing to mitigate risks. Key aspects to understand include new automatic database maintenance tasks, invisible indexes, workload capture and replay for application testing, and Adaptive Cursor Sharing to avoid bind variable peeking problems. Copying optimizer statistics and execution plans from the previous database version helps facilitate testing and reduce upgrade risks.
Upgrading to Oracle 11g from previous versions requires consideration of changes to default parameter values, new features like Automatic Memory Management and SQL Plan Management, potential plan instability issues, and testing to mitigate risks. Key aspects to understand include new automatic database maintenance tasks, invisible indexes, workload capture and replay for application testing, and Adaptive Cursor Sharing to avoid bind variable peeking problems. Copying optimizer statistics and execution plans from the previous version helps facilitate testing and rollback if needed.
This document discusses Oracle Database's flashback features, which allow users to view or recover past data and metadata. It describes flashback query, version query, transaction query, flashback transaction, flashback data archive, flashback table, flashback drop, and flashback database. These features require privileges like FLASHBACK and supplemental redo logging. They enable point-in-time data recovery without needing to restore backups. The document provides examples and best practices for configuring and using Oracle Database's flashback capabilities.
Exploring plsql new features best practices september 2013Andrejs Vorobjovs
The document discusses exploring new features and best practices in PL/SQL for better performance. It covers topics like parsing time, bulk binding, PL/SQL function result cache, subprogram inlining, finer grained dependencies, and new features in Oracle Database 12c. The presentation provides an overview of Oracle SQL Developer and guidelines for writing efficient and readable PL/SQL code.
AMIS organiseerde op maandagavond 15 juli het seminar ‘Oracle database 12c revealed’. Deze avond bood AMIS Oracle professionals de eerste mogelijkheid om de vernieuwingen in Oracle database 12c in actie te zien! De AMIS specialisten die meer dan een jaar bèta testen hebben uitgevoerd lieten zien wat er nieuw is en hoe we dat de komende jaren gaan inzetten!
Deze presentatie is deze avond gegeven in de vorm van een parallelsessie.
Oracle Database Performance Tuning Advanced Features and Best Practices for DBAsZohar Elkayam
Oracle Week 2017 slides.
Agenda:
Basics: How and What To Tune?
Using the Automatic Workload Repository (AWR)
Using AWR-Based Tools: ASH, ADDM
Real-Time Database Operation Monitoring (12c)
Identifying Problem SQL Statements
Using SQL Performance Analyzer
Tuning Memory (SGA and PGA)
Parallel Execution and Compression
Oracle Database 12c Performance New Features
DB12c: All You Need to Know About the Resource ManagerAndrejs Vorobjovs
Resource Manager has changed a lot in Oracle Database 12c, especially if Oracle Multitenant is used. It can manage the available resources between the consumer groups in a single PDB as well as among all the PDBs. DBAs who are planning the upgrades or consolidations to Oracle Database 12c need to understand how the new resource manager works and how the existing resource management plans need to be changed to make them work in the new Oracle Multitenant configuration.
This paper will explain the differences between 11g and 12c resource manager, will dig into resource management features and limitations in 12c Oracle Multitenant, will provide guidelines for migrating your current resource management plan to 12c at the time of upgrade or consolidation, and will also reveal how much overhead the resource manager introduces.
This document provides an overview and outline of a three-part presentation on tuning all layers of the Oracle E-Business Suite for performance. Part 1 will cover tuning application modules, upgrade performance best practices, and tuning the database tier. It will also discuss performance triage and resolution approaches. The presentation aims to provide guidance on configuration, operational best practices, patching, performance testing, and monitoring across the application, middleware, and database tiers to optimize E-Business Suite performance.
Antes de migrar de 10g a 11g o 12c, tome en cuenta las siguientes consideraciones. No es tan sencillo como simplemente cambiar de motor de base de datos, se necesita hacer consideraciones a nivel del aplicativo.
The document discusses Oracle database performance tuning. It covers identifying and resolving performance issues through tools like AWR and ASH reports. Common causes of performance problems include wait events, old statistics, incorrect execution plans, and I/O issues. The document recommends collecting specific data when analyzing problems and provides references and scripts for further tuning tasks.
Similar to 2009 Collaborate IOUG Presentation (20)
The document summarizes announcements from Oracle Open World 2019. It describes Oracle's Always Free tier which allows limited free use of databases, compute, storage and other services. It also discusses Oracle's partnerships with Microsoft and VMware to help customers migrate workloads between clouds. New services introduced include Autonomous Linux, expanded data centers, machine learning capabilities and improved security and database support offerings.
Using VirtualBox - Learn Oracle Database 12c and EBS R12Biju Thomas
VirtualBox allows users to run multiple operating systems on a single machine. It is free to use and install. This document discusses how to install VirtualBox, import pre-built Oracle and EBS virtual machines, and find various learning resources for working with Oracle Database 12c and EBS R12 using free virtual machines and VirtualBox. Tips are provided on testing configurations in VirtualBox before moving to a production Oracle VM Server environment.
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GLOC 2014 NEOOUG - R12 Upgrade Downtime ReductionBiju Thomas
This document discusses tips for reducing downtime when upgrading an Oracle E-Business Suite from version 11i to 12.1.3. It begins with an overview of the 12.1.3 upgrade process and prerequisites. A case study environment that upgraded from a single-instance 11i database to a RAC 12.1.3 database is described. Major phases of the upgrade are outlined and ways to reduce duration through tuning, such as optimizing storage, database parameters, and skipping unnecessary tasks, are provided. Considerations for choosing between upgrading to 12.1 or 12.2 are also reviewed. The presentation concludes with a list of Oracle documentation references.
Collaborate 2014 OAUG - EBS 11i Upgrade to R12 - Compare versions 12.2 vs 12.1Biju Thomas
This document provides a comparison of upgrading an Oracle E-Business Suite (EBS) 11i instance to release 12.1.3 versus 12.2.3. Key differences discussed include:
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Topics Covered:
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🔄 How APA is Different from RPA: Learn the key differences between Agentic Process Automation and Robotic Process Automation.
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Enhance your knowledge on the forefront of automation technology and stay ahead with Agentic Process Automation. 🧠💼✨
Speakers:
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-------------------------
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2009 Collaborate IOUG Presentation
1. Are You Using Flashback Yet?
Biju Thomas
OneNeck IT Services Corporation
http://www.oneneck.com (Booth 4364)
Session #330
2. About the Speaker
• Senior Database Administrator at OneNeck
IT Services Corporation (www.oneneck.com)
• More than 15 years of Oracle experience
• Author of OCA Oracle Database 11g Administrator
Certified Associate Study Guide published by Sybex
• Co-author of Oracle10g, Oracle9i & Oracle8i
Certification books published by Sybex
• Published articles in Oracle Magazine, Oracle
Internals and Select Journal
• Oracle 11g, 10g, 9i, 8i & 7.3
OCP Administrator
3. Introducing OneNeck
The ERP Outsourcing Experts
Provide a comprehensive, flexible suite of outsourcing
solutions designed specifically to help mid-market and
public sector organizations
• Supporting over 22,000 users at over 850 sites worldwide
• Primary data center/support center operations in Phoenix
and Houston
• Hosting and managing over 2000 databases
• 98% Contract Renewal Rate over 10 years
• 100% US based operations and staff
• 24x7x365 support center handling over 50,000 tickets
annually
• Oracle certified hosting partner
• Ranked #1 ERP Outsourcing Vendor by the Black Book of
Outsourcing three years in a row
• http://www.OneNeck.com
• Stop by booth 4364
4. Please remember to complete the
session evaluation form
Biju Thomas
Are you using Flashback yet?
Session # 330
5. Objectives
• Flashback Operations in Oracle Database
• What is Flash Recovery Area (FRA)?
• Configuring FRA
• Flashback Database
• Using & Maintaining FRA
• V$ Views for FRA and Flashback logs
7. Flashback Query
• Introduced in Oracle 9i R1
• Use DBMS_FLASHBACK package to enable
and disable flashback
• Must use Automatic Undo Management
• Only DML operations
• PL/SQL recognizes flashback
EXECUTE DBMS_FLASHBACK.ENABLE_AT_SYSTEM_CHANGE_NUMBER (n);
EXECUTE DBMS_FLASHBACK.ENABLE_AT_TIME (‘date_time‘);
EXECUTE DBMS_FLASHBACK.DISABLE;
8. Flashback Query #2
• Improvement in 9i R2
• AS OF TIMESTAMP and AS OF SCN clauses in query
• SYS user can use this clause
Examples:
INSERT INTO employees
SELECT * FROM employees as of timestamp
TO_TIMESTAMP('22-MAR-09 21:50', 'DD-MON-YY HH24:MI')
WHERE employee_id = 106;
EXP Parameter:
FLASHBACK_SCN=nnn
FLASHBACK_TIME="YYYY-MM-DD HH24:MI:SS" [9i fixed format]
FLASHBACK_TIME="TO_TIMESTAMP('31-MAR-09 12:00', 'DD-MON-YY
HH24:MI')" [specify format 10g onwards]
9. Flashback Query #3
• Example: Rows updated in EMPLOYEES table.
SELECT employee_id, first_name, last_name, salary
FROM employees AS OF TIMESTAMP
TO_TIMESTAMP('22-MAR-09 21:50', 'DD-MON-YY HH24:MI')
MINUS
SELECT employee_id, first_name, last_name, salary
FROM employees;
EMPLOYEE_ID FIRST_NAME LAST_NAME SALARY
----------- ------------- ---------------- ----------
103 Alexander Hunold 9000
106 Valli Pataballa 4800
10. Flashback Versions Query
• Introduced in Oracle 10g R1
• Shows all changes between a timeframe
VERSIONS BETWEEN [TIMESTAMP/SCN] .. AND ..
• Upper/Lower bound may be replaced with
MINVALUE and MAXVALUE to retrieve all
available data
• VERSIONS_ pseudo columns available –
STARTTIME, STARTSCN, ENDTIME,
ENDSCN, XID, OPERATION
11. Flashback Versions Query #2
• Example:
SELECT last_name, versions_starttime,
versions_endtime, versions_operation
FROM employees VERSIONS BETWEEN TIMESTAMP minvalue AND maxvalue
WHERE employee_id = 106
ORDER BY versions_starttime NULLS FIRST;
LAST_NAME VERSIONS_STARTTIME VERSIONS_ENDTIME V
------------- ---------------------- ---------------------- -
Pataballa 22-MAR-09 09.54.57 PM
Rojashin 22-MAR-09 09.54.57 PM 22-MAR-09 10.07.06 PM U
Hussaina 22-MAR-09 10.07.06 PM 22-MAR-09 10.14.04 PM U
Hussaina 22-MAR-09 10.14.04 PM D
Pataballa 22-MAR-09 10.17.21 PM I
12. Flashback Transaction Query
FLASHBACK_TRANSACTION_QUERY
• Introduced in Oracle 10g R1
XID
• Enterprise Edition only START_SCN
• Changes made to data at a START_TIMESTAMP
transaction level COMMIT_SCN
COMMIT_TIMESTAMP
• No need to use LogMiner LOGON_USER
• Reconstruct SQL to undo UNDO_CHANGE#
changes OPERATION
TABLE_NAME
• Need FLASHBACK ANY
TABLE_OWNER
TRANSACTON system privilege
ROW_ID
to query view UNDO_SQL
FLASHBACK_TRANSACTION_
QUERY
13. Flashback Transaction Query #2
SELECT operation, start_timestamp, undo_sql
FROM flashback_transaction_query
WHERE table_name = 'EMPLOYEES'
AND table_owner = 'HR';
OPERATION START_TIMESTAMP
UNDO_SQL
------------------------------------------------------
UPDATE 22-MAR-09 21:53:21
update "HR"."EMPLOYEES" set "FIRST_NAME" = 'Alexander', "SALARY" = '9000'
where ROWID = 'AAARAIAAFAAAABXAAD';
DELETE 22-MAR-09 22:14:04
insert into "HR"."EMPLOYEES“ ("EMPLOYEE_ID", "FIRST_NAME", "LAST_NAME“
,"EMAIL", "PHONE_NUMBER", "HIRE_DATE", "JOB_ID", "SALARY",
"COMMISSION_PCT", "MANAGER_ID", "DEPARTMENT_ID") values ('106', 'Valli',
'Hussaina', 'VPATABAL', '590.423.4560',TO_DATE('05-FEB-98 00:00:00', 'DD-
MON-YY HH24:MI:SS'),'IT_PROG','4800',NULL,'103','60');
INSERT 22-MAR-09 22:17:13
delete from "HR"."EMPLOYEES" where ROWID = 'AAARAIAAFAAAABYAAJ';
14. Flashback Table (Drop)
• Introduced in Oracle 10g R1 (EE)
• Recover a dropped table (does not use UNDO)
DROP TABLE job_history;
Table dropped.
SHOW RECYCLEBIN
ORIGINAL NAME RECYCLEBIN NAME OBJECT TYPE DROP TIME
-------------- ------------------------------ ------------ -------------------
JOB_HISTORY BIN$ZcGwtQ/sKCbgQAB/AQBl2g==$0 TABLE 2009-03-22:23:27:54
FLASHBACK TABLE job_history TO BEFORE DROP;
Flashback complete.
• Option to rename table
FLASHBACK TABLE jobs TO BEFORE DROP RENAME TO jobs_march;
15. Flashback Drop #2
• Recycle bin automatically cleared when
tablespace is under “space pressure”
• Options for manually clearing space:
PURGE TABLE <name> PURGE RECYCLEBIN
PURGE INDEX <name> PURGE DBA_RECYCLEBIN
PURGE TABLESPACE <name> DROP TABLE <name> PURGE
PURGE TABLESPACE <name>
USER <name>
• To disable recyclebin:
– 10gR1: _recyclebin parameter
– 10gR2+: recyclebin parameter
16. Flashback Table #3
• Reinstate table to a previous state using
TIMESTAMP or SCN (uses UNDO)
• ROW MOVEMENT should be enabled.
ALTER TABLE employees ENABLE ROW MOVEMENT;
Table altered.
FLASHBACK TABLE employees TO TIMESTAMP
TO_TIMESTAMP('22-MAR-09 21:50', 'DD-MON-YY HH24:MI');
Flashback complete.
17. Flashback Database
• Introduced in Oracle 10g R1 (EE)
• Quickly rewind a database to fix any issues
• Similar to point-in-time recovery, but much
faster
• Uses flashback logs, a before image of
changed blocks
• Flashback logs saved in Flash Recovery Area
(FRA)
• 10g R2 introduced restore points and the
ability to flashback through RESETLOGS
18. Flashback Transaction
• Introduced in Oracle 11g R1 (EE)
• Use to undo changes made by transaction
• Uses UNDO and redo logs (archive logs too)
• Requires supplemental logging of primary key
ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY) COLUMNS;
• Enterprise Manager or PL/SQL interface
– Under “Availability” tab, click “View and Manage
Transactions”
– DBMS_FLASHBACK.TRANSACTION_BACKOUT
procedure
20. Flashback Data Archive
• Introduced in Oracle 11g R1 (EE)
• Total Recall Option – separate license.
• Automatically track and maintain changes to data in
an application transparent and secure manner.
• Uses AS OF construct in SQL.
• Historical data can be kept for any specified duration
– not dependent on undo or flashback log data.
• RETENTION specified in the data archive.
• New background process “fbda” captures historic
information in a non-intrusive manner.
• New record added to history table only for update &
delete statements.
21. Settings for Undo Flashback
• Enabling automatic Undo
– UNDO_MANAGEMENT = AUTO
• Parameters controlling amount of undo retained:
– UNDO_RETENTION
• Guaranteed retention option available
– ALTER TABLESPACE <undots> RETENTION
GUARANTEE
• Flashback Operations using Undo
– FB Query, FB Versions Query, FB Transaction, FB
Transaction Query, FB Table
23. Flash Recovery Area
• Area of disk location where recovery related
files are stored
• Managed via Oracle Managed Files
• Free space automatically managed by
Oracle, obsolete files under current retention
policies are deleted when space needed.
• Can act as a disk cache for backup files
before writing to tape
• Flashback logs required to use the Flashback
database feature are created only in FRA
24. Flash Recovery Area #2
• Need to specify the disk quota.
• Preferable to be on a different disk where
database files are not stored.
• Permanent and transient files can be stored –
permanent files are copies of redo logs and
control file.
• FRA can be on ASM disk
• Oracle server alerts monitors the reclaimable
space in FRA
25. Configuring FRA
• DB_RECOVERY_FILE_DEST_SIZE
– Specify the maximum space allocated for FRA
• DB_RECOVERY_FILE_DEST
– Location of the FRA
• For RAC databases, all instances must have
same values
• DB_FLASHBACK_RETENTION_TARGET
– Specify in minutes how much flashback log
information should be retained – Default 1440.
26. FRA Contents
• Permanent Files
– Copy of control file
– Copy of redo log files
• Transient Files
– Archive log files
– Flashback logs
– RMAN control file and spfile autobackup
– RMAN image copies & backup sets
Example File Name:
/u05/flash_recovery_area/11GR11/backupset/2009_03_26/o1_mf_
annnn_TAG20090326T004654_4wp5rntg_.bkp
27. Sizing FRA
• Bigger the FRA, more useful it becomes
• Recommendation: DB Size + Incr backups +
archive logs + flashback logs
• Flashback logs generated are approximately
similar in size to redo logs generated.
• If there is not enough free space in FRA,
flashback logs are deleted to make room.
29. Configuring Flashback
• Enable flashback on the database in mount
state.
SHUTDOWN IMMEDIATE;
STARTUP MOUNT;
ALTER DATABASE FLASHBACK ON;
ALTER DATABASE OPEN;
• Flashback logs will be written to FRA, and
oldest logs deleted when FRA becomes full.
• Database must be in ARCHIVELOG mode.
30. Flashback a Database
• To flashback a database is similar to
performing a point-in-time recovery
• RESETLOGS required to open database.
SHUTDOWN IMMEDIATE;
STARTUP MOUNT;
FLASHBACK DATABASE TO [BEFORE] [SCN | TIME |
SEQUENCE ] = value;
ALTER DATABASE OPEN RESETLOGS;
• Archive logs may be used to fill-in the gaps
31. Using Restorepoints
• Introduced in Oracle 10g R2
• Very useful when performing planned
maintenance
• Option to guarantee flashback
CREATE RESTORE POINT before_patch;
CREATE RESTORE POINT before_patch GUARANTEE
FLASHBACK DATABASE;
FLASHBACK DATABASE TO RESTORE POINT before_patch;
DROP RESTORE POINT before_patch;
32. Using Flashback for DR Testing
• Setup FRA and enable flashback logs in the standby
database
• Create a restore point to go back to
• Disable log transport to standby database from primary
• Activate the standby database and open database.
• When testing is completed, revert back to the restore
point using FLASHBACK DATABASE.
• Convert the database to physical standby again
• Catch up the standby database to primary database
• Enable log transport from primary
33. Standby Redo-apply Delay`
• Oracle provides time delay in applying the
archivelogs to the standby database to delay the
propagation of errors and corruption to standby
database.
• By having flashback logging on the standby
database, you can always flashback the standby
database, thus eliminate using time-delay.
• You can flashback and open the standby database,
get the rows/tables that were messed up and put the
standby database back in recovery mode.
• This helps to avoid outage to primary database for
non-critical data recovery.
35. Automated RMAN Backups
• When no FORMAT clause is specified for
RMAN backups, they go into FRA.
• Automatic controlfile and spfile backups may
be configured to go to FRA.
• Consider keeping image copies in FRA, with
incrementally updated backups (and with
optional rolling window)
RUN
{ RECOVER COPY OF DATABASE WITH TAG 'daily_incr'
UNTIL TIME 'SYSDATE - 3';
BACKUP INCREMENTAL LEVEL 1 FOR RECOVER OF COPY WITH TAG
'daily_incr' DATABASE;
}
36. RMAN FORMAT Clause
• If you perform RMAN disk backups with the
FORMAT clause specifying the FRA location,
they are not managed by Oracle and not
considered for FRA cleanup and FRA space
management algorithm.
• So, to backup to FRA, do not specify the
FORMAT clause, the default location is the
FRA for RMAN backups when FRA is
configured.
RMAN> CONFIGURE CHANNEL DEVICE TYPE DISK CLEAR;
37. Backing up FRA
• FRA can be backed up only using RMAN
RUN {
ALLOCATE CHANNEL CH01T TYPE sbt_tape;
BACKUP RECOVERY AREA;
}
• Flashback logs, the current control file, and
online redo logs are not backed up.
• This statement can only back up to a tape
device, disk is not supported.
38. Using LOG_ARCHIVE_DEST_n
• If you explicitly specify the FRA location in the
LOG_ARCHIVE_DEST_n parameter, the
archive logs are not considered in the FRA
space management algorithm and they are
not backed up when you specify the BACKUP
RECOVERY AREA command.
• The correct specification is
log_archive_dest_n=
'LOCATION= USE_DB_RECOVERY_FILE_DEST'
39. FRA Full Errors
• Once the Flash Recovery Area is full, Oracle
automatically deletes eligible files to reclaim space in
the Flash Recovery Area as needed.
• Oracle may delete flashback logs from the earliest
SCNs to make room for other files.
• Alert log errors:
ORA-19809: limit exceeded for recovery files
ORA-19804: cannot reclaim <nnnnn> bytes disk
space from <mmmmm> limit
ORA-19815: WARNING: db_recovery_file_dest_size of
<size of FRA configured> bytes is 100.00% used,
and has 0 remaining bytes available.
40. Resolving Full FRA
• Make more space available by adjusting
DB_RECOVERY_FILE_DEST_SIZE.
• Backup the contents of the Flash Recovery
Area to a tertiary device such as tape.
• Change backup retention policy.
CONFIGURE RETENTION POLICY TO RECOVERY WINDOW
OF 7 DAYS;
• Change archive log deletion policy.
CONFIGURE ARCHIVELOG DELETION POLICY TO BACKED
UP 1 TIMES TO SBT;
42. Backups/Logs Using FRA
• Find out if backups and archive logs are part
of the FRA algorithm
– IS_RECOVERY_DEST_FILE column in
V$BACKUP_PIECE
– IS_RECOVERY_DEST_FILE column in
V$ARCHIVED_LOG
43. V$RECOVERY_FILE_DEST
• Find out the current location, disk quota, space in
use, space reclaimable by deleting files, and total
number of files in the Flash Recovery Area.
SQL> select * from v$recovery_file_dest;
NAME
SPACE_LIMIT SPACE_USED SPACE_RECLAIMABLE NUMBER_OF_FILES
------------ ------------ ----------------- --------------
/u01/app/oracle/flash_recovery_area
15728640000 9448377344 10272768 213
44. V$FLASH_RECOVERY_AREA_USAGE
• Find out the percentage of the total disk quota used by different
types of files. Determine how much space for each type of file can
be reclaimed by deleting files that are obsolete, redundant, or
already backed up to tape.
SQL> SELECT FILE_TYPE, PERCENT_SPACE_USED USED, PERCENT_SPACE_RECLAIMABLE RECLAIM,
NUMBER_OF_FILES FILES FROM V$FLASH_RECOVERY_AREA_USAGE;
FILE_TYPE USED RECLAIM FILES
-------------------- ---------- ---------- ----------
CONTROL FILE 0 0 0
REDO LOG 0 0 0
ARCHIVED LOG 61.66 51.2 216
BACKUP PIECE 19.07 9.7 31
IMAGE COPY 4.93 .4 8
FLASHBACK LOG 1.24 0 9
FOREIGN ARCHIVED LOG 0 0 0
45. V$FLASHBACK_DATABASE_LOG
• Estimate how far back you can rollback the
database using flashback logs, and estimated
size based on retention target.
SQL> select * from v$flashback_database_log;
OLDEST_FLASHBACK_SCN OLDEST_FL RETENTION_TARGET FLASHBACK_SIZE
-------------------- --------- ---------------- --------------
ESTIMATED_FLASHBACK_SIZE
------------------------
8257936 25-MAR-09 1440 194478080
4303306752
46. Items Learned in this Session
• Flashback Operations
– Think of flashback before saying “no” or getting
ready to recover
• Flash Recovery Area
– It’s worth even if you use it just for flashback logs
– Do not specify FORMAT clause for RMAN or
directory name for archive log destination
• Flashback Database
– Good for critical patching activities, migrations
– Use restorepoints
48. Thank You…
• Please complete the session evaluation form
– Biju Thomas
– Are you using Flashback yet?
– Session # 330
• Further questions, comments…
– Stop by Booth # 4364
– WWW.ONENECK.COM