Oracle 参数 CONTROL_FILE_RECORD_KEEP_TIME 官方解释，作用，如何配置最优化建议
本站中文解释
参数
CONTROL_FILE_RECORD_KEEP_TIME 参数指定多少天后，操作系统上的控制文件备份记录会被自动删除。根据实际情况，它一般被设置为7天。如果参数设置正确，控制文件备份可以保存在操作系统端备份记录长达7天。
正确设置这个参数的方法主要有以下几点：
1、确定定期备份控制文件的频率，以确定控制文件备份记录应保留多长时间。
2、将 CONTROL_FILE_RECORD_KEEP_TIME 参数设置为与控制文件备份频率相一致的值，以确保控制文件备份记录能够保留足够长的时间。
3、确保 CONTROL_FILE_RECORD_KEEP_TIME 参数的值不得大于控制文件备份记录能保留的最大时间，以免导致控制文件备份记录不能保存。
官方英文解释
CONTROL_FILE_RECORD_KEEP_TIME specifies the minimum number of days before a reusable record in the control file can be reused.
| Property | Description |
|---|---|
|
Parameter type |
Integer |
|
Default value |
|
|
Modifiable |
|
|
Modifiable in a PDB |
No |
|
Range of values |
|
|
Basic |
No |
In the event a new record must be added to a reusable section and the oldest record has not aged enough, the record section expands. If this parameter is set to 0, then reusable sections never expand, and records are reused as needed.
If the number of reusable records in the control file exceeds the circular reuse record limit UB4MAXVAL, then reusable records will be overwritten even if CONTROL_FILE_RECORD_KEEP_TIME has not elapsed. UB4MAXVAL is defined in the oratypes.h header file, which is found in the public directory. Its value may vary according to the operating system you are using.
Note:
This parameter applies only to records in the control file that are circularly reusable (such as archive log records and various backup records). It does not apply to records such as data file, tablespace, and redo thread records, which are never reused unless the corresponding object is dropped from the tablespace.
See Also:
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“CONTROL_FILES”
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Oracle Database Backup and
Recovery User’s Guide for more information about this parameter
