Portions of the LOB are passed sequentially by the client application to the database until the entire LOB has been transmitted.
Deferred mode means that the system passes a 4-byte integer token identifying the LOB with the non-LOB data in the initial request. While in MultiPart Request mode, the database elicits the LOB data from the client with an ElicitData parcel, providing the token to identify the desired LOB data. A maximum-sized LOB can be passed in this way without knowing the LOB data size in advance.
However, simple deferred mode does not work well with client utilities that may not know the location of the LOB data on the client. Therefore, use the BY NAME phrase whenever you specify the AS DEFERRED option.
When you specify the AS DEFERRED BY NAME option, the LOB data is represented in the data sent with the request as a VARCHAR value limited to 1,024 bytes. The database processes AS DEFERRED BY NAME as a simple AS DEFERRED, with the exception that when the AMP wants to elicit the LOB data from the client, the AMP uses a ElicitDataByName parcel, which identifies the LOB by the name passed by the client in the initial request, rather than an ElicitData parcel, which identifies the LOB by the LOB token that was originally passed by the client.