FRA restore_point

Flashback log Files Older Than OLDEST_FLASHBACK_TIME Not Deleted .What is TYPE Reserved in v$flashback_database_logfile (Doc ID 2369101.1)

Here are the reasons why the FRA is running out of space:

1/ According to the alert.log, there are several 'Deleted Oracle managed file ........' messages,
   which indicates that Oracle is trying to delete the flashback logs.
   Also, there are a lot of 'Unable to allocate flashback log', which means that the flash recovery area (FRA) is running out of space.

2/ According to the results of the query on V$FLASH_RECOVERY_AREA_USAGE,
   the flashback logs consumed 61.845 GB of the FRA or 99.75% of the FRA size, which is 66571993088 (or 62 GB).

   According to the V$FLASHBACK_DATABASE_LOGFILE, there are 225 flashback logs with a size of 297066496 (or 283 MB).
   [ 297066496 bytes x 225 = 66839961600 bytes (or 62.25 GB) ]

3/ The wait event 'Flashback buf free by RVWR' is related to the frequent maintenance of the FRA,
   which is deleting the flashback logs, because the FRA is running out of space.
 

Note: If the Recovery Writer process (RVWR) is constantly busy deleting the flashback logs,
       because the FRA size is not large enough, then the RVWR can't keep up writing the flashback log records.
       As a result, the sessions trying to add to the buffer cache will receive a “flashback buf free by RVWR”
       while the RVWR catches up.

SOLUTION

Run the following SQL command to Increase the FRA size, as shown here. Please provide the appropriate FRA size.

SQL> alter system set db_recovery_file_dest_size=200G scope=both;

 

FRA视图

       1. DBA_OUTSTANDING_ALERT：从FRA中添加或删除文件时事件将会记录在警告日志中。可以检查新的DBA视图DBA_OUTSTANDING_ALERT来了解关于FRA一些选著问题的信息。空间相关问题产生的时间和警告出现在DBA_OUTSTANDING_ALERT中的时间存在一定程度的延迟。

        2.V$RECOVERY_FILE_DEST：提供在数据库中定义的FRA的概述。提供配置的FRA的大小、所使用的空间数量、可以回收多少空间，以及FRA中的文件数量。该视图中包含SPACE_RECLAIMABLE列，该列指示有可回收的空间，该空间由归档的重做日志或备份集占用，根据已选择的标准，已不再需要这些空间。

       3. V$FLASH_RECOVERY_AREA_USAGE：FRA空间各个文件类型的详细信息。该视图对文件类型进行分组，然后根据每个文件类型所使用的空间百分比、来自于该组的总FRA可回收空间百分比，以及来自于改组的FRA文件数量。

        注：手工删除FRA中固定的文件会产生无法预料的结果，Oracle不会立刻检测出这些文件是否删除，所以也不会收回相应的空间。如果最终手工删除文件，则使用RMAN

        crosscheck结合delete命令来使Oracle更新FRA上的当前控制文件信息。