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快速理解Oracle归档模式的命令及参数

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Oracle数据库可以运行在两种模式下:归档模式(archivelog)和非归档模式(noarchivelog)。 检查归档模式命令: SQL> archive log list Database log mode No Archive Mode Automatic archival Disabled Archive destination USE_DB_RECOVERY_FILE_DEST Oldest online log sequence 15 Current log sequence 17 设置归档模式: ;SQL> shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down. SQL> startup mount ORACLE instance started. Total System Global Area 1258291200 bytes Fixed Size 1219160 bytes Variable Size 318768552 bytes Database Buffers 922746880 bytes Redo Buffers 15556608 bytes Database mounted. SQL> alter database archivelog; Database altered. SQL> alter database open; Database altered. SQL> archive log list; Database log mode Archive Mode Automatic archival Enabled Archive destination USE_DB_RECOVERY_FILE_DEST Oldest online log sequence 15 Next log sequence to archive 17 Current log sequence 17 假如需要停止归档模式,使用:alter database noarchivelog 命令。Oracle10g之前,你还需要修改初始化参数使数据库处于自动归档模式。在pfile/spfile中设置如下参数: log_archive_start = true 重启数据库此参数生效,此时数据库处于自动归档模式。也可以在数据库启动过程中,手工执行: archive log start 使数据库启用自动归档,但是重启后数据库仍然处于手工归档模式。10g使用db_recovery_file_dest来作为归档日志的存放地。 SQL> show parameter db_recovery NAME TYPE VALUE db_recovery_file_dest string /home/oracle/ora10g/flash_reco very_area/ db_recovery_file_dest_size big integer 20G 可以修改db_recovery_file_dest_size参数的大小 alter system set db_recovery_file_dest_size=21474836480