11.4.18 Unarchiving chunks (when using an archivable multi-chunk table)

To unarchive chunks in an archivable multi-chunk table (to release chunks from archived state), execute the adbunarchivechunk command. The following shows the procedure.

Procedure:

Identify the chunks that you want to release from archived state.

Identify the chunks that you want to release from archived state by using the value in the archive range column. If you execute the adbunarchivechunk command with the -r and -t options specified, you can identify the IDs of chunks that are included in the value range in the archive range column.

Specification example

This example identifies the chunks whose date information in the archive range column includes a date between January 1, 2015 and January 31, 2015.
```
adbunarchivechunk -u ADBUSER01 -p '#HelloHADB_01'
                  -r '2015/01/01-2015/01/31'
                  -t
                  SALESLIST
```
If you execute the adbunarchivechunk command with the -r and -t options specified, KFAA80245-I message is output. In the KFAA80245-I message, you can determine the IDs of the chunks that are included in the date range specified for the -r option.
Check the data size after the archived state is released.

If you release chunks from archived state, the data size increases. Make sure that there is no problem if the data size increases. To check the data size of chunks after they are released from archived state, execute the adbdbstatus command with the -c archivechunk and -n options specified to output the archived chunk summary information. For the -n option, specify the name of the archivable multi-chunk table in which the chunks to be released from archived state are contained.

In the archived chunk summary information, check the following information about the chunks to be released from archived state:
- Unarchive_table_size (Size of the segments used for storing tables in an unarchived chunk)
- Unarchive_index_size (Size of the segments used for storing indexes in an unarchived chunk)
The sum of the preceding values becomes the guideline for the data size (for table data and index data) of the chunks that have been released from archived state.
Release chunks from archived state.

If there is no problem in the data size after the archived state is released, execute the adbunarchivechunk command to release the chunks from archived state. When executing the preceding command, specify for the -c option the chunk IDs identified in step 1.

Specification example

This example releases the chunk whose chunk ID is 5 from archived state.
```
adbunarchivechunk -u ADBUSER01 -p '#HelloHADB_01'
                  -w /home/adbmanager/tmp
                  -z /home/adbmanager/unarchive_file/unarchive_opt_file.txt
                  -c 5
                  SALESLIST
```
Note

When you execute the adbunarchivechunk command, you can specify the -r option, instead of the -c option. In this case, specify the value range in the archive range column for this option to specify the chunks to be released from archived state.

To check whether the chunks in the specified range have been released from archived state, execute the adbdbstatus command with the -c archivechunk and -n options specified to output the archived chunk summary information. For the -n option, specify the name of the archivable multi-chunk table in which the chunks released from archived state are contained. Then, check the following information:

Range_min (Minimum value for the archive range column)
Range_max (Maximum value for the archive range column)

To check the data size of chunks that have been released from archived state, execute the adbdbstatus command with the -d used, -c table, and -n options specified to output the usage information. For the -n option, specify the name of the archivable multi-chunk table in which the chunks released from archived state are contained. Then, check the following information:

Used_segments (Number of segments being used)
Used_pages (Number of pages being used)
Note
- If you execute the adbunarchivechunk command, the HADB server creates a temporary chunk, which is used by the system to release chunks from archived state. Therefore, even if you perform background import or merge of chunks after executing the adbunarchivechunk command, the ID of the created chunk will not be the number increased by one from the ID of the chunk previously created.
- For details about the adbunarchivechunk command, see adbunarchivechunk (Unarchive Chunk) in the manual HADB Command Reference.
- For details about the adbdbstatus command, see adbdbstatus (Analyze the Database Status) in the manual HADB Command Reference.

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