When using the assign activity in Oracle BPEL Process Manager or Oracle Mediator to manipulate large payloads, do not assign the complete message. Instead, assign only the part of the payload that you need.

In addition, when using the assign activity in Oracle BPEL Process Manager, Oracle recommends using local variables instead of process variables, wherever possible. Local variables are limited to the scope of the BPEL process. These get deleted from memory and from the database after you close the scope. However, the life cycle of a global variable is tied with the instance life cycle. These variables stay in memory or remain on disk until the instance completes. Thus, local variables are preferred to process or global variables.