Partial object restore or retrieve

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The application client can receive only a portion of the object. This is called a partial object restore or a partial object retrieve.

Attention: Partial restore or retrieve of compressed or encrypted objects produces unpredictable results.

Note: If you code your application to use a partial object restore or retrieve, you cannot compress the data while sending it. To enforce this, set ObjAttr.objCompressed to bTrue.

To perform a partial object restore or retrieve, associate the following two data fields with each object GetList entry:

offset: The byte offset into the object from which to begin returning data.
length: The number of object bytes to return.

Use DSM_MAX_PARTIAL_GET_OBJ to determine the maximum number of objects that can perform a partial object restore or retrieve for a specific dsmBeginGetData list.

The following data fields, used on the dsmBeginGetData call, determine what portion of the object is restored or retrieved:

If both the offset and length are zero, the entire object is restored or retrieved from IBM® Storage Protect storage.
If the offset is greater than zero, but the length is zero, the object is restored or retrieved from the offset to the end.
If the length is greater than zero, only the portion of the object from the offset for the specified length is restored or retrieved.