- · SMON performs the roll forward process by applying changes recorded in the online redo log files from the last checkpoint
· Rolling forward recovers data which including the contents of rollback segments
· Rollback can occur while the database is open, because either SMON or a server process can perform the rollback operation.
· RMAN uses the large pool for backup and restore when you set the DBWR_IO_SLAVES or BACKUP_TAPE_IO_SLAVES parameters to simulate asynchronous I/O.
· When the database is set to Archive log mode, the LGWR process waits for the online redo log files to be archived(either manually or through the ARCn process) before they can be reused.
· An Oracle database cannot be opened unless all datafiles redo logs, and control files are synchronized.
· During Recovery Archived and online redo log files recover committed transactions and roll back
Uncommitted transactions to synchronize the database files.
· Archived and online redo log files are automatically requested by the oracle server during the recovery phase. Make sure logs exist in the requested location.
Roll forward (redo)
Roll back (undo)
· Undo segments are populated during the roll forward phase.
· You can restore a backup copy of the damaged files and use archived log files to bring the data files up-to-date while the database is online or offline.
· You can recover the database to a specific point in time.
· You can recover the database to the end of a specified archived log file.
· You can recover the database to a specific system change number(SCN).
· Setting the database in Archivelog mode does not enable the Arciver(ARCn) processes.
· The dynamic parameter LOG_ARCHIVE_MAX_PROCESSES controls the number of archive processes started at instance startup.
· When LOG_ARCHIVE_START is set to TRUE, an Oracle instance starts up with as many archiver processes as defined by LOG_ARCHIVE_MAX_PROCESSES.
ALTER SYSTEM ARCHIVE LOG LOG_ARCHIVE_DEST_n
· Only one archive destination per remote database can be specified.
· Although it is not mandatory to create a recovery catalog to use RMAN, it is beneficial to use a recovery catalog. The recovery catalog should be located in a database different from the target database.
TSPITR(tablespace point-in-time recovery)
· The following commands change the database configuration and result in changes to control file.
alter database [adddrop] logfile
alter database [adddrop] logfile member
alter database [adddrop] logfile group
alter database [noarchivelogarchivelog]
alter database rename file
create tablespace
alter tablespace [addrename] datafile
alter tablespace [read writeread only]
drop tablespace
· If you are performing a closed backup, the target database must not be open. If you are using a recovery catalog,the recovery catalog database must be open.
SBT_tape (System Backup to Tape)
· select * from v$recover_file The CHANGE# column returns the SCN (system change number) from where recovery must start.
· Recovery manager uses the recovery catalog or target database control file to determine which full or incremental backups or image copies it will use during restoration.
· To restore to a previous point in time, you may have to use the backup of an older control file and use the restore control file option. The database should be in nomount state to restore the control file.
· Incomplete recovery is typically used when a complete recovery operation fails.
Time-based recovery
Cancel-based recovery
Change-based recovery
· A retention policy specifies when RMAN should consider the backups and copies it creates as obsolete.
· The recovery catalog is a schema that is created in a separate database. it contains the RMAN metadata obtained from the target database control file. RMAN propagates information about the database structure, archived redo logs, backup sets, and datafile copies into the recovery catalog from the control file of the target database.
· You should use a catalog when you have multiple target databases to manage. Recovery Catalog contains information on: datafile and archived redo log file backup sets and backup pieces. datafile copies. Archived redo log files. The physical structure of the target database. Persistent RMAN configuration settings. Stored job scripts.
· These objects share the same namespace:
Tables,
Views,
Sequences, Private synonyms,
Procedures,
Functions, packages, materialized views, user defined types.
· The database has separate namespaces for each of the following:
Indexes, contraints, clusters, database triggers, private database
Links, dimensions, roles, public synonyms, public database
Links, tablespaces, profiles, PFILES.
· A shared server process executes each request and places the completed request in the dispatcher’s response queue.
· An Oracle 10g database supports four levels (statement, privilege, object, and fine-grained access) of auditing.
· The SYS and SYSTEM accounts are the data dictionary owner and an administrative account, respectively SYSMAN and DBSNMP are used by EM.
· Oracle offers three authentication methods for your user accounts: password authentication (the most common) external authentication, and global authentication.
· Automatic shared memory management : Use MMAN(Memory Manager) Process
· In the shared serve configuration user session data and cursor state are stored in large pool (inside SGA) and stack space are stored outside SGA ( PGA)
· In the dedicated server configuration PGA contains user session, cursor state and stack space.
· locale manage & dictionary manage
· NLS_LANG=_ .
· alter session set nls_language=english
· Parameter files(PFILEs) and server parameter files(SPFILEs)
· private synonym , public synonym
· tablespace, segment, extent, block
· Schema Objects: tables, triggers, constraints, indexes, views, sequences, stored
Program units, synonyms, user-defined data types, database links
· SBT_tape (System Backup to Tape)
I will Keep on adding to the series like Part 1 part 2 and son on of the Exam Notes series......
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