To restore a database, it is necessary to specify in the pdrstr command the unload log files in time series (according to generations). Therefore, before transferring the unload log files to another medium, create a time series list of unload log files. When the database is restored, refer to this list to identify the required unload log files.
This section explains how to create a time series list of unload log files and how to identify the unload log files required for database restoration.
Because the names of the unload log files created by the automatic log unloading facility are in the format shown below, the unload log files in the directory for unload log files are arranged in time series order:
server-name_server-run-ID-and-generation-number_file-group-name
Figure 3-7 shows how to create a time series list of unload log files.
Figure 3-7 Creating a time series list of unload log files (using a single directory for unload log files)
Because the names of the unload log files created by the automatic log unloading facility are in the format shown below, the unload log files in the directory for unload log files are arranged in time series order:
server-name_server-run-ID-and-generation-number_file-group-name
Figure 3-8 shows how to create a time series list of unload log files.
Figure 3-8 Creating a time series list of unload log files (using multiple directories for unload log files)
Care must be taken when 0000 is shown as the generation number for a system log file. When generation numbers are in the range from ffff to 0000 under the same server run ID, the unload log files are not arranged in time series order. An example follows in which unload log files are not arranged in time series order.
Files in a directory for unload log files
bes1_3a765d820000_logfg04 "0000" is shown. |
In this case, the unload log files were created in the sequence shown below, so they must be used in this sequence:
You must check that there are no missing files in the time series list of unload log files. When the server run ID is the same, either the generation numbers increment by 1 or different file group names are used under the same generation number.
If this is not the case, an unload log file may be missing. If a required unload log file is missing, it is necessary to unload again the system log files for the missing information. If the system log files have already been overwritten and unload log files cannot be created, the database cannot be restored to the most recent synchronization point. In such a case, the database can be restored only to the point where the most recent backup was made.