LOG_ARCHIVE_FORMAT

LOG_ARCHIVE_FORMAT

Property	Description
Parameter type	String
Syntax	LOG_ARCHIVE_FORMAT = filename
Default value	Operating system-dependent
Modifiable	No
Range of values	Any string that resolves to a valid filename
Basic	No
Real Application Clusters	Multiple instances can have different values, but identical values are recommended.

LOG_ARCHIVE_FORMAT is applicable only if you are using the redo log in ARCHIVELOG mode. Use a text string and variables to specify the default filename format when archiving redo log files. The string generated from this format is appended to the string specified in the LOG_ARCHIVE_DEST parameter.

The following variables can be used in the format:

%s log sequence number

%S log sequence number, zero filled

%tthread number

%Tthread number, zero filled

%a activation ID

%d database ID

%r resetlogs ID that ensures unique names are constructed for the archived log files across multiple incarnations of the database

Using uppercase letters for the variables (for example, %S) causes the value to be fixed length and padded to the left with zeros. An example of specifying the archive redo log filename format follows:

         LOG_ARCHIVE_FORMAT = 'log%t_%s_%r.arc'

Neither LOG_ARCHIVE_DEST nor LOG_ARCHIVE_FORMAT have to be complete file or directory specifiers themselves; they only need to form a valid file path after the variables are substituted into LOG_ARCHIVE_FORMAT 

and the two parameters are concatenated together.

 

 Oracle 10g开始,log_archive_format初始化参数必须包含%s, %t 和 %r,以确保生成的归档重做日志名称唯一.

（原因：10g能做穿越resetlog的恢复，所以要加%r。而9i的不能做穿越resetlog的恢复，所以没有%r的参数）