2.14.1 About background import

HADB provides the background-import facility to enable concurrent execution of data retrieval and data importing.

Applying the background-import facility for importing data enables you to perform data-retrieval and data-storage processes concurrently for the same table.

The following figure provides an overview of background import.

Figure 2‒41: Overview of background import

Explanation

Retrieving data stored in table T1 and storing data in table T1 by means of background import can be performed concurrently.

Note that the data being imported using background import becomes retrievable after the data-storage process is completed.

Note

If you want to retrieve data and store a large amount of data concurrently, we recommend that you use the background-import facility. If you want to retrieve data and store a small amount of data concurrently, consider using an SQL statement (INSERT statement) instead of the background-import facility so as not to reduce the data storage efficiency. For details, see 5.2.4 Points to consider in defining a multi-chunk table.

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