Identification of logical-log files

Each logical-log file, whether backed up to media or not, has a unique ID number. The sequence begins with 1 for the first logical-log file filled after you initialize the database server disk space. When the current logical-log file becomes full, the database server switches to the next logical-log file and increments the unique ID number for the new log file by one. Log files that are newly added or marked for deletion have unique ID numbers of 0.

The actual disk space allocated for each logical-log file has an identification number known as the log file number. For example, if you configure six logical-log files, these files have log numbers one through six. The log numbers might be out of sequence. As logical-log files are backed up and freed, the database server reuses the disk space for the logical-log files.

The following table illustrates the relationship between the log numbers and the unique ID numbers. Log 7 is inserted after log 5 and used for the first time in the second rotation.
Table 1. Logical-log file-numbering sequence
Log file number First rotation unique ID number Second rotation unique ID number Third rotation unique ID number
1 1 7 14
2 2 8 15
3 3 9 16
4 4 10 17
5 5 11 18
7 0 12 19
6 6 13 20

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