2.1.1 Functional overview
When the adbarchivechunk command is executed, table data can be archived (compressed) in units of chunks. The archiving of data in units of chunks is called chunk archive processing. In addition, tables whose data can be archived in units of chunks are called archivable multi-chunk tables.
When chunk archive processing is executed, the target chunk data is compressed and stored in a file (archive file). That data is also deleted from the DB area files.
The following figure provides an overview of chunk archive processing.
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![[Figure]](GRAPHICS/F0000001.GIF)
- Explanation:
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When the adbarchivechunk command is executed, data stored in the chunks specified in the archivable multi-chunk table is searched. That data is stored as an archive file in the archive directory.
After the archive file is stored, the specified chunk data is deleted from the DB area files.
Note that multiple chunks can be archived during one execution of the adbarchivechunk command. When multiple chunks are archived, the storage processing and deletion processing is repeated as many times as the number of chunks.
The following chunks can be archived (are subject to archiving) by the adbarchivechunk command.
- ▪ Chunks that are subject to archiving
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Chunks in normal status
However, the current chunk cannot be archived.
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Chunks in wait status that have once been in normal status in the past
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- Important
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A disadvantage of archived chunks is that search processing on their corresponding chunk data is slowed down. Make sure that you take into account the preceding point before deciding whether to use chunk archive processing.
For details about archiving chunks, see Chunk archiving function (compressing data in a chunk) in the HADB Setup and Operation Guide.