Modern Oracle DBA

Oracle database Release number format: Example of an Oracle Database Release Number 11.2.0.1.0 11->Major database release number The first digit is the most general identifier. It represents a major new version of the software that contains significant new functionality. 2->Database maintenance release number The second digit represents a maintenance release level. Some new features may also be included. 0->Fusion Middleware release number The third digit reflects the release level of the Oracle Application Server (OracleAS). 1->Component specific release number The fourth digit identifies a release level specific to a component. Different components can have different numbers in this position depending upon, for example, component patch sets or interim releases. 0->Platform specific release number The fifth digit identifies a platform-specific release. Usually this is a patch set. When different platforms require the equivalent patch set, this di

Alert Log file The alert log file keep record the following information: When DB start or down    List of all non default initialization parameter    The startup of background process    Information regarding a log switch    Creation of table space and Undo segments    Alter statement that have been issued    Information regarding error message Alert log location The Oracle alert log location of determined by the background dump destination and specified by the background_dump_dest parameter. SQL>  show parameter background NAME                                 TYPE        VALUE ------------------------------------ ----------- ------------------------------ background_core_dump                 string      partial background_dump_dest                string      /oracle/app/oracle/diag/rdbms/PROD/PROD/trace ADRCI:-   Automatic Diagnostic repository(ADR) in oracle database   [testora@v

OPatch It is a java based utility used mainly for installing patches and interim patches (bug fixes). Opatch requires that OUI is installed     List of Database Patches One-off patches (e.g. a bug fix) Critical Patch Update (CPU) Upgrade patches (bug fix bundle) Patch Set Update (PSU) Bundled patches (For Windows and Exadata only) Upgrade OPatch version Upgrade your version of opatch search on Oracle Support for patch number 6880880 and click one of the results Download the latest OPatch p6880880_112000_Linux-x86-64.zip Make a backup of the actual OPatch and make sure there is no OPatch folder on $ORACLE_HOME folder (EX) cd $ORACLE_HOME mv OPatch OPatch_old Unzip the patch into $ORACLE_HOME unzip p6880880_112000_Linux-x86-64.zip -d $ORACLE_HOME Apply steps Step 1:-Backup database Step 2:-Backup database Home path (Ex):- tar -cvf patch_bkp /u01/oracle/ STEP 3:-Check OPatch version (Ex):- opatch version STEP 4:- Shutdown database and listener 

What is archive log:   Copy redo log files to a designated storage device after a log switch has occurred ARCHIVE processes are present only when the database is in ARCHIVELOG mode and automatic archiving is enabled. An archived redo log file is a copy of one of the filled members of a redo log group. It includes the redo entries and the unique log sequence number of the identical member of the redo log group.    Database Running in noarchivelog Mode: When you run your database in NOARCHIVELOG mode, you disable the archiving of the redo log The database control file indicates that filled groups are not required to be archived NOARCHIVELOG mode protects a database from instance failure but not from media failure Only the most recent changes made to the database, which are stored in the online redo log groups, are available for instance recovery. In NOARCHIVELOG mode you cannot perform online  backups Database  Running in archivelog Mode: When you run a database