2.15.1 Overview of the chunk archiving function

Data such as sensor data and sales data increases by a large amount every day. If you need to store such data for a long term, the storage capacity might become low or the cost of adding storage might exceed your expectation. If you are dealing with such problems, you can compact the database size by compressing and outputting the data in the DB area to a file. This processing is called archiving. Data can be archived on a chunk basis. This is called the chunk archiving function.

The following figure shows an overview of archiving data by using the chunk archiving function.

Figure 2‒52: Archiving data by using the chunk archiving function

Explanation

1. The data in a chunk is compressed and output (archived) to a file. This file is called an archive file. When a chunk is archived, one or more archive files are created.

   The directory in which archive files are stored is called an archive directory.

   Only table data is archived. Index data is deleted without being archived.

2. When a chunk is archived, the data in the chunk is deleted.

   A chunk whose data has been archived is called an archived chunk.

The preceding sequence of tasks is called chunk archiving. To archive a chunk, execute the adbarchivechunk command.

Note

If the chunk archiving function is used, the database size can be reduced. However, searching archived data might take longer than searching non-archived data for the following reasons:

• Time is required to expand the data.

• Index-based searches cannot be performed.

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