orcl0(oraclearchitecturalcomponents)-資料下載頁
2025-02-16 15:01本頁面
【正文】 he instance and open the database: STARTUP [FORCE] [RESTRICT] [PFILE=filename] [OPEN [RECOVER][database] |MOUNT |NOMOUNT] OPEN enables users to access the database MOUNT mounts the database for certain DBA activities but does not provide user access to the database NOMOUNT creates the SGA and starts up the background processes but does not provide access to the database PFILE=parfile enables a nondefault parameter file to be used to configure the instance FORCE aborts the running instance before performing a normal startup RESTRICT enables only users with RESTRICTED SESSION privilege to access the database RECOVER begins media recovery when the database starts 40 The ALTER DATABASE Command ? Change the state of the database from NOMOUNT to MOUNT: ALTER DATABASE db01 MOUNT。 ? Open the database as a readonly database: ALTER DATABASE db01 OPEN READ ONLY。 41 Opening a Database in Restricted Mode ? Use the STARTUP mand to restrict access to a database: ? Use the ALTER SYSTEM mand to place an instance in restricted mode: STARTUP RESTRICT ALTER SYSTEM ENABLE RESTRICTED SESSION。 42 Opening a Database in ReadOnly Mode ? A databases can be opened as a readonly database. ? A readonly database can be used to: – Execute queries – Execute disk sorts using locally managed tablespaces – Take data files offline and online, not tablespaces – Perform recovery of offline data files and tablespaces 43 Shutting Down the Database Shut down the database to make operating system offline backups of all physical structures and to have modified static initialization parameters take effect. To shut down an instance you must connect as SYSOPER or SYSDBA and use the following mand: SHUTDOWN [NORMAL | TRANSACTIONAL | IMMEDIATE | ABORT ] 44 Shutting Down the Database Shutdown Mode: ? NORMAL ? TRANSACTIONAL ? IMMEDIATE ? ABORT A x x x x T x x o o I x x x o Shutdown Mode Allow new connections Wait until current sessions end Wait until current transactions end Force a checkpoint and close files N x o o o YES NO x o 45 Shutdown Options During a Shutdown Normal, Shutdown Transactional or Shutdown Immediate Consistent Database (clean database) On the way down: ? Database buffer cache written to the data files ? Unmitted changes rolled back ? Resources released. On the way up: ? No instance recovery 46 Shutdown Options During a Shutdown Abort or Instance Failure or Startup Force Inconsistent Database (dirty database) On the way down: ? Modified buffers are not written to the data files ? Unmitted changes are not rolled back On the way up: ? Redo logs used to reapply changes ? Undo segments used to roll back unmitted changes ? Resources released 47 演講完畢，謝謝觀看！
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