Creating Near-Line Storage Connections

You can call the transaction for processing near-line storage either in Customizing under SAP Customizing Implementation Guide  SAP NetWeaver   Business Warehouse  General BW Settings  Edit Near-Line Storage Connection or in the Data Warehousing Workbench under Administration  Current Settings  Near-Line Storage Connections.

Choose New Entries.

Enter a name for the near-line storage connection. This name is then offered to you for selection when you create a data archiving process.

Enter the name of the class that implements the near-line storage connection.

• Productive ( ):

  This is the recommended mode for productive use. Every operation on the near-line connection is passed on to the near-line provider. Especially when processing queries, these are terminated with an error message if near-line storage is not available unless a pruning mechanism has excluded the near-line access in advance.

• Emergency (E):

  This mode can be used if near-line storage is temporarily unavailable. In this mode, queries that run over the Data Manager return empty result sets from every near-line provider that is assigned to this near-line connection. A warning message is sent to the front end aswell. All other operations, for example moving data into or out of near-line storage (like archiving and restoring), data extraction from the near-line storage (for ETL processes in BW) or creating new near-line tables/editing existing ones, terminate with an error message, without the corresponding near-line interface method being called. You can use this mode if near-line storage crashes or has to be switched off for maintenance. In particular, this mode covers queries that the near-line access do not exclue already by means of an explicit definition (near-line read mode) or a successful pruning mechanism.

  If you set the near-line connection to this mode, you should issue a system message informing users that results in the queries might be incomplete.

• Read-Only (R):

  This mode is the same as productive mode, with the difference that no operations can be transferred to near-line storage if this would change the status with regard to the BW system. This means that no DDL commands (create, edit and store near-line tables) or DML commands (create, edit near-line requests, open writer handles) are allowed at the near-line interface level. If a BW process triggers a command of this type, it receives an exception with an error message indicating that the command is not possible in this mode.

  This mode can be used during system migration for example if both the original system and the copied system should use the near-line storage. In this case, the mode has to be set in both systems of course.

• Off (O):

  This mode should be used if a near-line storage has been permanently disconnected from the BW system, but there are still active data archiving processes (DAPs) in the BW system. In this mode, all DDL and DML commands returns an error message with an exception. Errors of type DROP_TABLE are ignored in order to allow deletion of DAPs without having to connect the BW system with near-line storage again. Every read access on near-line data returns an empty result set, as the system expects all near-line requests and the corresponding data to be deleted.

If you have made an entry under Database Connection, this overrides the entry under Conn. Parameter.

The entries for the Destination and Connection Parameter field are made by your near-line storage solution. For more information on individual parameters, see the F1 help.

Save your entries. When you save, the connection to the near-line storage solution is opened and then closed again. Near-line storage solution then returns a status indicating whether the connection is working and providing system information. In the upper area of the screen, the system displays the connection, with its status and system information. The log is displayed in the lower part of the screen.