Database Actions to Take Before Archiving (SAP Library

Database Actions to Take Before Archiving

You should decide whether or not to archive after considering all the circumstances, because storing data places new demands on performance if, after archiving, access to the data is required.

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

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. This procedure is described in the BC Basis document Database Administration (SAPDBA for Oracle and Informix) or ABAP/4 Dictionary, section Tablespaces and Extents (database-independent parameters for ADABAS).

Will you need to access the archived data again? 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.

Is the data accessed using an optimal index?
An appropriate index may exist, but may not be used. This depends on the database optimizer.

You can check which index is actually used to access data by Performing an SQL Trace.

The BC Basis documentation ABAP/4 Dictionary contains more information about indices. Use the keyword "Index".

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.

Reorganization takes a long time and may need to be repeated after archiving.

Duration ca.:

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

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