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Database Actions Before ArchivingLocate this document in the navigation structure

Use

Archiving application data helps to prevent storage and performance bottlenecks. Since relocating data can, in some circumstances, in itself, impair performance - this is the case if you need to access archived data - you need to consider carefully what data to archive.

To determine whether or not you should archive data, consider the following questions:

  • For memory problems: Can more memory be assigned to the table (MAXEXTENT, Tablespace)?

    If the answer is yes, and if you will need to access the archived data and you have no performance problems, you should consider enlarging the table. You can find the exact description in the SAP NetWeaver AS Documentation SAP Database Guide: Oracle (BRSPACE for Oracle) or ABAP Dictionary, section Tablespaces und Extents database-independent parameterization, MaxDB).

  • How likely is it that you will need to access the archived data again and how often?

    If you need to access the archived data often and there are no performance problems, assign more memory to the tables in question (see above).

  • For performance problems: Are you using an optimal index for the access?

    In some circumstances, a suitable index may be available but not being used. This depends on the database optimizer.

    You can check which index is actually used to access data by Performing an SQL Trace. For more information on indexes, refer to the SAP NetWeaver AS documentation ABAP Dictionary and search for appropriate sections using "index" as your search term.

  • Does the application perform a full table scan on the tables that contain the data to be archived?

    If the answer is yes and the table is fragmented, it may help to reorganize the table before archiving so that new records and any records that remain in the database are physically contiguous.

    Caution

    Note that reorganization takes a long time and may need to be repeated after archiving.

    Throughput during a reorganization:

    - With export/import: approximately. 60-100 MByte/hour

    - With unload/load: approximately. 250-300 MByte/hour