Monday, April 16, 2007

Oracle9i DBA -- Database: Fundamentals I (3)

Managing an Oracle Instance


  • IFILE can additional files be added to the PFILE.
  • STARTUP and SHUTDOWN of database are the option available to SYSDBA and SYSOPER.
  • IFILE is a handy way to modularize and version the parameter files, but there is a limit of specifying only three nesting levels. If exceeded Oracle will generate an error.
  • DB_NAME is a database identifier of eight characters or less.
  • V$SESSION obtained the information about SID and the Serial#
  • The alert_SID.log location is defined by the BACKGROUND_DUMP_DEST initialization parameter. The default location on Unix is $ORACLE_HOME/rdbms/log.
  • In the read-only mode DB recovery can take place.
  • PROCESS initialization parameter: It determines the maximum no of OS processes that can connect to the instance.It determines the value for the number of background processes.
  • For maximum compatibility the UNDO_MANAGEMENT INITIALIZATION parameter of Oracle 9i Database should to be set to manual.
  • LICENCE_MAX_SESSIONS is used to define the number of concurrent sessions that are allowed to connect to the 9i DBA.
  • USER_DUMP_DEST directory has the trace files generated by user sessions, specifies location for user process errors.User trace file size is determined by MAX_DUMP_FILE_SIZE, default is 10MB. CORE_DUMP_DEST is used on unix platforms to save the core dump files. BACKGROUND_DUMP_DEST is used to set the directory path where the alert log file is written. Log background process errors.
  • Instance failure is automatically fixed by SMON process, when the instance is restarted by using STARTUP OPEN command on the SQL or the Server Manager.
  • SPFILE doesn’t contain statements that are only comment lines, while PFILE may have complete comments.
  • MOUNT is the level where Control file is read, Data files are read at OPEN level.
  • The initialization parameter is in ORACLE_HOME\dbs
  • STARTUP FORCE will always abort a running instance before performing a normal startup. Can be used to reconnect to an already connected and running instance, and requires instance recovery.

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